Intake runner size for 582 BBC -tech help-

[r8ceredy]

A question for the collective experience of RJ. I am working on a 582 Dart low deck BBC. (4.600boreX4.375stroke) I am building this for pump gas, 10.5:1 compression and wondering what size heads to run on it. I am looking at a set of aluminum Dart Pro 1 and they are offered in 325cc,345cc and 355cc for the same $$$. I thought the 325cc might not flow enough for the cubic inches, even though they would probably be the most responsive on the velocity theory. I will run a Comp Cam solid roller 256-263* @ .050 duration, .660 lift camshaft(3500-7500). The car weighs roughly 3300# and I have a 4.56 gear, th400 w/3500 stall, and Hoosier Quick time pro 11.0" tires. The car is 90% street, seeing occasional 1/4 fun. Big post here, but want your opinion on intake runner size. Thanks

[lmchevy]

If you are going to use an as cast head then go with the pro1 345.The 355 darts you mentioned is cnc ported and is about $1000 more than the as cast head.

[superstreeter]

what are you running for dynamic compression, with say a 118 cc head?

[cboggs]

That combo will want the largest of the heads you posted, . . .

The Dart Pro 1 355 is a fully CnC ported head and sells for $3600 complete.
The pro 1 345 is the as cast head, sells for around $2600 a set complete.

I have an Edelbrock Victor head that we designed and CnC in-house
I'll sell you complete for $3300, flows 450cfm, ..

Curtis

[r8ceredy]

Static compression with the 118 is 10.5:1 for pump gas use. I don't intend on nitrous, but the sickness might take over if the car don't run a good number :twisted: :twisted: :twisted:

[r8ceredy]

That combo will want the largest of the heads you posted, . . .

The Dart Pro 1 355 is a fully CnC ported head and sells for $3600 complete.
The pro 1 345 is the as cast head, sells for around $2600 a set complete.

I have an Edelbrock Victor head that we designed and CnC in-house
I'll sell you complete for $3300, flows 450cfm, ..

Curtis
What kind of throttle response & street manners will a big intake runner have? As much as I want to have quick times at the track I do putt around town to car shows and cruise nights where the motor is rarely much over the stall of the torque convertor. Is a 850 cfm single 4bbl sufficient to supply fuel? I have a Holley black (150gph I believe)electric fuel pump and regulator that I hope I can reuse. I have been watching some sets of Dart Pro One aluminums 345cc with 2.30 intake valves for $2000 delivered. When I contact the sellers the usual upgrade charge for springs able to handle up to .700 lift roller cam is $150. I don't mind spending a few extra bucks as long as the payoff is worth it. I've had luck selling some car extras here on RJ so now is the time to "re-invest" in my money pit. For comparison sake, what does a set of as cast pro 1 345s flow and how would the difference realistically make on my motor?

[Pwmax]

With that rather small cam for a 582, and 345 Pro-1's, you will not have to worry about throttle response. It will be VERY tqy and responsive at low rpm. Actualy, if that engine is going into the car in your sig, it will probably twist it in half. You will definately have no trouble spinning the tires.

Frank
Advanced Performance
www.get-ap.com

[r8ceredy]

With that rather small cam for a 582, and 345 Pro-1's, you will not have to worry about throttle response. It will be VERY tqy and responsive at low rpm. Actualy, if that engine is going into the car in your sig, it will probably twist it in half. You will definately have no trouble spinning the tires.

Frank
Advanced Performance
www.get-ap.com

No replacement for displacement right?
I'm gonna run a small tire so I don't pretzel it. Some frame ties but no cage. Car is too valuable to cut up IMO. I took the original driveline and crated it. Now I have a 9",th400, and this engine for fun.

[r8ceredy]

Anyone else's .02?

[russ67chevelle]

latest trend seems to be run largest lift with moderate to lower duration cams for 3000-7000 rpm range.i cant wait to see what superstreeters dyno says this winter cause i have a 572 and compiling info for a new cam this winter.......

[superstreeter]

I talked to quite a few people about the same thing, and for that size of engine they recommend a 335 - 355 with a dynamic of about 7.5 - 8.0 for pump gas, thats why I asked you earlier what your dynamic was? you have a small cam but we don`t know all the specs. but it should still be close to the 8.0 . lots of different heads out there, that are really good, you just need to have someone sell you,on a set, that they are running. I`m sure you already have a manufacturer in mind. my opinion for what you have would be the 325- 335 with that size of cam

[r8ceredy]

I talked to quite a few people about the same thing, and for that size of engine they recommend a 335 - 355 with a dynamic of about 7.5 - 8.0 for pump gas, thats why I asked you earlier what your dynamic was? you have a small cam but we don`t know all the specs. but it should still be close to the 8.0 . lots of different heads out there, that are really good, you just need to have someone sell you,on a set, that they are running. I`m sure you already have a manufacturer in mind. my opinion for what you have would be the 325- 335 with that size of cam
superstreeter, not to sound stupid, but what do you mean by "dynamic"? I have always heard good things about Dart Pro 1s so that is the way I was leaning, but I am open to another set of aluminum BBC heads for around $2k if someone has a suggestion.
Thanks for your advise. :)

[a13badazztoys]

Dynamic Compression Ratio
The calculated compression ratio, as given above, presumes that the cylinder is sealed at the bottom of the stroke (bottom dead center - BDC), and that the volume compressed is the actual volume.

However: intake valve closure (sealing the cylinder) always takes place after BDC, which causes some of the intake charge to be compressed backwards out of the cylinder by the rising piston at very low speeds; only the percentage of the stroke after intake valve closure is compressed. This "corrected" compression ratio is commonly called the "dynamic compression ratio".

This ratio is higher with more conservative (i.e., earlier, soon after BDC) intake cam timing, and lower with more radical (i.e., later, long after BDC) intake cam timing, but always lower than the static or "nominal" compression ratio.

The actual position of the piston can be determined by trigonometry, using the stroke length and the connecting rod length (measured between centers). The absolute cylinder pressure is the result of an exponent of the dynamic compression ratio. This exponent is a polytropic value for the ratio of variable heats for air and similar gases at the temperatures present. This compensates for the temperature rise caused by compression, as well as heat lost to the cylinder. Under ideal (adiabatic) conditions, the exponent would be 1.4, but a lower value, generally between 1.2 and 1.3 is used, since the amount of heat lost will vary among engines based on design, size and materials used, but provides useful results for purposes of comparison. For example, if the static compression ratio is 10:1, and the dynamic compression ratio is 7.5:1, a useful value for cylinder pressure would be (7.5)^1.3 × atmospheric pressure, or 13.7 bar. (× 14.7 psi at sea level = 201.8 psi. The pressure shown on a gauge would be the absolute pressure less atmospheric pressure, or 187.1 psi.)

The two corrections for dynamic compression ratio affect cylinder pressure in opposite directions, but not in equal strength. An engine with high static compression ratio and late intake valve closure will have a DCR similar to an engine with lower compression but earlier intake valve closure.
:roll: :roll: :roll:

[Racefab57]

WOW!!!!!!!!!!!!!!!GREAT STUFF,David.

[Pwmax]

Here is one of those situations again, when its a street car, where, a guy is worried about loosing "low end tq". Not bashing anyone here, just trying to put a different perspective on that whole magazine phrase. I would agree, its a lot easier making power with more cubic inches for sure, but this is a case where its going to be rediculously over kill, which, some guys like, lol.

That cam is way to small for a 582. It will make all the tq low in the rpm band, where, that car will NEVER hook it. In fact, it will be down right dangerous. I have customers with more 100 less cubic inches, that have put similiar cars, in the ditch, and almost wrecked the car, or died, because the car got completelty out of control. One guy, called me and told me he switched tires, because he was killing his Hoosier quick time pros, before he even made it to the track, so he put his old BFG Radial T/A's on it, to save his good tires. I said, be very careful. Huh he said. I said, don't do what you used to, going 50-60mph on the highway, drop it into second, from drive, and hammer it. Why? You will end up in the ditch. He didn;t listen. Called me a few days later, and told me you were right. Going 50, dropped it into second, hammered it, and ended up in the ditch on the other side of the road, faster than he could react. Car lit the tires, got out of shape, he paniced, lost control, and put it in the ditch. Did about $2000 worth of body work damage, and lucky he didn;t get killed.

That was only 461 cubes, that made 600hp, and 575 tq. Thats 1 story, there are others. With 582 inches, and monster tq, my guess, would be somewhere over 750+ ft/lbs at fairly low rpm, 4500, somewhere in there, with the above combo, in that chassis, it will be hairy. If that sounds fun, than do it, but, just be careful is all I am saying.

If you think about it, trying to kill low end power in a true street car, with limited tires, and chassis, is a good idea. Purposely do things to reduce tq, and shift peak power up top. This thing will make a ton of power regardless, and still be a tire frier supreme. Thats just my advice from expierience.

Frank
Advanced Performance
www.get-ap.com

[r8ceredy]

Here is one of those situations again, when its a street car, where, a guy is worried about loosing "low end tq". Not bashing anyone here, just trying to put a different perspective on that whole magazine phrase. I would agree, its a lot easier making power with more cubic inches for sure, but this is a case where its going to be rediculously over kill, which, some guys like, lol.

That cam is way to small for a 582. It will make all the tq low in the rpm band, where, that car will NEVER hook it. In fact, it will be down right dangerous. I have customers with more 100 less cubic inches, that have put similiar cars, in the ditch, and almost wrecked the car, or died, because the car got completelty out of control. One guy, called me and told me he switched tires, because he was killing his Hoosier quick time pros, before he even made it to the track, so he put his old BFG Radial T/A's on it, to save his good tires. I said, be very careful. Huh he said. I said, don't do what you used to, going 50-60mph on the highway, drop it into second, from drive, and hammer it. Why? You will end up in the ditch. He didn;t listen. Called me a few days later, and told me you were right. Going 50, dropped it into second, hammered it, and ended up in the ditch on the other side of the road, faster than he could react. Car lit the tires, got out of shape, he paniced, lost control, and put it in the ditch. Did about $2000 worth of body work damage, and lucky he didn;t get killed.

That was only 461 cubes, that made 600hp, and 575 tq. Thats 1 story, there are others. With 582 inches, and monster tq, my guess, would be somewhere over 750+ ft/lbs at fairly low rpm, 4500, somewhere in there, with the above combo, in that chassis, it will be hairy. If that sounds fun, than do it, but, just be careful is all I am saying.

If you think about it, trying to kill low end power in a true street car, with limited tires, and chassis, is a good idea. Purposely do things to reduce tq, and shift peak power up top. This thing will make a ton of power regardless, and still be a tire frier supreme. Thats just my advice from expierience.

Frank
Advanced Performance
www.get-ap.com

Frank, that is the advise I am looking for. I have always ran SBC and am finding out this is a whole 'nother ball game. What general cam specs would you recommend for a solid roller to lose some bottom and gain more middle to upper band? I still don't want to rev much over 7500 for parts livability. I am buying good parts that are all on the overkill side of things because I am tired of building an engine that is "just enough" and wanting to go faster only to have to tear the engine apart and throwing $$$ out the window. With my previous small blocks if the heads/cam were too big it was a DOG on the street that wasn't much fun. I laugh at myself for what I am doing so I don't take offense for anyone's comments and truly appreciate the feedback. :oops: :oops: :oops:

[Pwmax]

You won;t have to rev it 7500. If all you had were mushy small blocks in the past, this combo will be a huge eye opener. As far as cams go, is this going to be a weekend type fun car, or do you plan to run it cross country? If it were mine, I would be building it on the more radical side, as I don't really cruise my car all that far in a givin trip. That many cubes will need a fairly large cam. Not necessarily lift, but, duration. The more lift the better obviously, but then you get into more longevity issues with lifters and springs.

If it were mine, I would put a cam in it that had a lot more duration than most guys would even consider for a " street" car, but, like I said, I live no more than 15 miles from numerous cruise spots where I live, and, I am big into drag racing, so, if I built a big engine like that, I would want to take advantage of it. With that said, I would have 2 sets of intake rockers, like a 1.6 and a set of 1.8 or 1.85:1. Use the low ratio rackers on the street to keep the loads down, and max it out with the high ratio rockers for the track. Knowing me though, I would just run the 1.8's all the time, and just keep tabs on overthing. But, I would be in the 280 range at .050, with .800+ lift, with wide lobe sep. If thats too radical, then something in the 270's, with mid .700's would be good, and I would use a lobe that wasn;t quite as aggressive, like a Comps Hi-Tech roller lobes.

To know for sure on the cam, what your plans are with the car, and what you want to do with it need to be known.

Frank
Advanced Performance
www.get-ap.com

[a13badazztoys]

He did state that this was a 90% street car.... Not a 90% race car... :roll:

[Pwmax]

Didn;t see the 90% street part, sorry. :roll: There is an eye roll back to you. Then, if thats the case, i wouldn;t build a 582. I would build a 509, or a 532 with a 4.6 inch bore, if you want more cubes, which you won;t need. In which case, I would use a big custom high lift hydraulic roller cam, with good lifters, and the right springs. Crane lifters, will rev 7000. I know how most guys think, have been around this stuff a long time. I know he says 90% street, but, he wouldn;t be thinking 582 and solid roller, if he didn;t want big power. I know a mild 582, would give a huge kick in the shorts, but, I think he might be disapointed with the top end. It wouldn;t really matter anyhow, because in that car, it will never hook. Even a 509 makes crazy power for a street car.

Case in point, I know of numerous guys who have bought 502 and 572 Gm core engines, and, were totaly disapointed. Decently snappy on the bottom, but then are dead before 6000. So, it blows the tires off, then falls on its face because there is nothing left. I have revamped at least 5 502's, and one 572 after 1 summer for that very reason. One guy with a 572 in a chevelle got smoked by one of my customers, in his super budget 496, and was mad. They got to talkin, and I fixed it up. 770hp from 620, and it was no less streetable. The 502's get turned into 509's, and make 730 and 660 on the tq. Thats basicaly 225hp, from a cam, and porting the heads.

Frank
Advanced Performance
www.get-ap.com

[SVRE]

That was only 461 cubes, that made 600hp, and 575 tq. Thats 1 story, there are others. With 582 inches, and monster tq, my guess, would be somewhere over 750+ ft/lbs at fairly low rpm, 4500, somewhere in there, with the above combo, in that chassis, it will be hairy. If that sounds fun, than do it, but, just be careful is all I am saying.


Very true.

Here is another one.

I built a customer a 505 and used his junk pro comp heads. After putting in seats, some weld in the chambers, and port work, they ended up about 370cc and went 380-390cfm with a 2.300 valve. 10.5:1 compression. custom 262 274 @ .050 on a 110 with .720" with jesel 1.75 rockers. Edelbrock port matched super victor with a 1050 holley.
Made 742 hp @ 6900. The man just KNEW he needed 700hp. Now he rides around and wastes about 200 on the street. Has good response and drives good, just too much for a street car without good suspension. Wheel hops at 80mph.
But if your after big power, im with curtis. Go big with it.

I have done a few others with bigger cams, but this one drives the best. More dangerous also though!

Steve

[Pwmax]

Thats what I am saying. Steve's 505 has heads that would be considered by anyone reading this thread, to be WAAAY to big at 370cc on a 505 "street" engine, but, it is still out of control

Now, like I said, I am one for totaly overdoing it, and, if you want to build a 582 then do it. I was just trying to point a few things out to him is all. In that chassis, unless its really set up well, and you use sticky tires, it still won;t hook on the street, short of being tubbed. And, can be dangerous to boot. I also gave that advise, because if you build an engine like that, put small heads on it, and a way to small cam, it will peak power early, and quit. If you ran a 2.73 gear, and a tight converter, it could work I suppose, but that will kill performance too, making it not worth building that combo. Note: These are my opinions, based from expierience, I am sure some of you disagree with my thought processes. Which is fine. I just don;t see the point of building an engine like that and running no gear, and a tight converter, to kill tq multiplication, of an engine you built, to make big tq. Doesn;t make sense to me. I would rather build something a bit smaller. Heck, even a nice 496 with big block would be absolutely killer in that thing, even a 461 with 048's, or 781's, and a mild solid cam would be.

Frank
Advanced performance
www.get-ap.com

[Tod74]

I am nobody compaired to these guys here...but just my .02 cents.

You will ruin that car. I only say that because you mentioned crating the original drive trane...which leads me to believe you don't want a ragged out "street race" type car..you want to keep it nice. With no cage,( and a 582) if you take that to the track much at all with good tires (if it hooks up)you will have that car a mess.Door and fender gaps etc. Just my opinion.

[r8ceredy]

You won;t have to rev it 7500. If all you had were mushy small blocks in the past, this combo will be a huge eye opener. As far as cams go, is this going to be a weekend type fun car, or do you plan to run it cross country? If it were mine, I would be building it on the more radical side, as I don't really cruise my car all that far in a givin trip. That many cubes will need a fairly large cam. Not necessarily lift, but, duration. The more lift the better obviously, but then you get into more longevity issues with lifters and springs.

If it were mine, I would put a cam in it that had a lot more duration than most guys would even consider for a " street" car, but, like I said, I live no more than 15 miles from numerous cruise spots where I live, and, I am big into drag racing, so, if I built a big engine like that, I would want to take advantage of it. With that said, I would have 2 sets of intake rockers, like a 1.6 and a set of 1.8 or 1.85:1. Use the low ratio rackers on the street to keep the loads down, and max it out with the high ratio rockers for the track. Knowing me though, I would just run the 1.8's all the time, and just keep tabs on overthing. But, I would be in the 280 range at .050, with .800+ lift, with wide lobe sep. If thats too radical, then something in the 270's, with mid .700's would be good, and I would use a lobe that wasn;t quite as aggressive, like a Comps Hi-Tech roller lobes.

To know for sure on the cam, what your plans are with the car, and what you want to do with it need to be known.

Frank
Advanced Performance
www.get-ap.com

Frank,
I live within 20 miles of most any cruise/show that I will attend so I agree with a little more on the exotic side. My engine list thus far is Dart 9.8 block, Eagle rotating assembly, and dart pro one heads or similiar. I can pick up the short block for under $4k and the heads for $2k. It doesn't seem to matter if I want to build a 502 or 582 - roughly same money. I would like to think that I am similiar to a lot of weekend warriors that want to run full on race cars like some of the big guys on here, but will probably never gut out my show car for the maximum effort car. I would rather tone down a bigger cube motor now, than have to throw a ton of money at a smaller engine to make the same hp at the track. I can sense that I am causing quite a few of you veteran builders to scratch your head and laugh, but I do value everyone's input as it will surely keep me from making stupid mistakes.
8) Thanks 8)

[Pwmax]

You already have me worried. I am not trying to sell you a thing here either. But, I have a very good idea, where you are thinking about getting this short block and heads from. And, all I can say is, cheap is cheap. Under $4000 for a 582 short block, and under $2k for the heads. I know where it is, and all I can say is, keep your fingers crossed, and I will wish you luck. Don't believe me, go to the scammers section, on this sight and take a peak.

You will get a finished hone block, washed and stuffed with cam bearings, and called race prepped. You will get a generic balance job, that was done to a "universal bob weight". Meaning, they weighed a set of rods, similiar pistons, rings and bearings, at some time in the past, and, thats the bob weight they use for EVERY one they do like that. How can you precision balance a rotating assembly, when none of the parts have ever been un-boxed? Every piston still wrapped up, bearings never opened, rings never opened, every rod still in its un opened platic bag, etc. Then, some 20 year old kid, who gets a bonus for getting them together faster hammers the thing together, not one clearance is checked or verified, and presto, you have a "Race engine". The heads, are pulled out of the box, dusted off, the valves stuffed in, a spring shim put under the springs, and wing bang boom, your "race prepped" heads are ready to bolt on!! Some work, many don't. I know of a few guys who have fallen victim to the cheapest race engine shop in the world, and they are amongst the slowest guys at the track. One guy even refers to his 565 he got there, that was supposedely over 940hp, as the worlds slowest 565. In a 2800 lbs, trick 65 chevy 2, that was done by a local chassis shop that build killer cars, that went in the 7's when they had, it now barely goes 9.30's, on the bottle!!. It should run 8.60-70's or faster, on the motor, with that power.

As apposed to how I do it, and how it should be done. Block gets deburred, I re-tq the mains, and check main housing bore sizes, many times, I add arp studs, and re-dust the mains on the line hone, depending on application. The block gets BHJ block trued and re-cut decks for a smooth Ra finish, to use cometic or other mls gaskets. And set deck heights. Dart does a good job, and they are within .005, but, I want them at .0001. Thats 1 tenth. The cylinders are usualy bored and then tq plate honed with a plataeu type honing procedure, that Dart recomends. We do it exactly like they say to. Multiple grit stones, to get the Ra and Rz values correct. Then whatever rotating parts are used, every compnenet is weighed, and adjusted as necessary, then, the bob weight is done up, and the crank is balanced to less than .5 grams. Not even going to get into the assembly procedures, or the head prep. But, thats the correct way to do it. Obviously I charge more, and I won;t sell as many, but guess what, I don;t deal with tons of headaches from un-happy customers, and I don;t have numerous court litigations pending.

Frank
Advanced Performance
www.get-ap.com

[r8ceredy]

You already have me worried. I am not trying to sell you a thing here either. But, I have a very good idea, where you are thinking about getting this short block and heads from. And, all I can say is, cheap is cheap. Under $4000 for a 582 short block, and under $2k for the heads. I know where it is, and all I can say is, keep your fingers crossed, and I will wish you luck. Don't believe me, go to the scammers section, on this sight and take a peak.



I agree and luckily have already read the threads on certain Nevada shops. The pricing I was talking about was just for parts. I have a reputable shop local here that will take the parts and do what you were talking me through. I have been burned in the past and consider myself "wiser" now. My point was that the aftermarket blocks don't seem so bad as an alternative price wise to a 40 year old GM unit that had such wide variences to start with, then overboring and hoping the walls are thick enough if there wasn't core shift, and then being limited to bore size. The rotating assemblies cost roughly the same if your talking 496 to 598 so why not go big :twisted: Right? :twisted:

[JLSTOEC]

Pwrmax, I like your thought about running different ratio rockers arms as a means of changine the cam profile. Generally speaking if someone is switching from 1.7 ratio to 1.8 on a BBC does the pushrod length change as well? I currently run 1.7 ratio on a solid roller and would like to try 1.8 in lieu of changing cams. Thanks.