compression

Old 01-13-2012, 12:58 PM
  #21  
cncmotorsports
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Originally Posted by roadkill2
Thanks Guys, we're just trying to see what our options are before getting froggy and buying this coming year's backup short block, which, will end up being next year's Bullet if all goes well this coming season . . As I said, I'm not closely familiar with Big Inch BBCs and the Boss was just getting his feet wet this last year . . We ask questions because we want the shortest learning curve available and it's a hell of a lot easier (and cheaper) to get answers from those of you who might have them, than to learn them the hard way . .

Not that we're lost, as we've been in the money twice last year . . We just wanna do it as easily as possible . . Hell, I'm an old guy, I'm tired of climbing mountains and fighting thunderstorms . . There's a bunch of know how here and I'd love to share what I've learned about other classes of drag racing with guys who're successful in the brackets . .

Bracket racing is a whole hell of a lot different than either heads up or index racing . . But most of you know that . .

On the Headwork, they've been massaged by Steve Schmidt (former Pro Stocker and engine builder) and are all CNC . . At this point the heads aren't close to their potential, I believe, as we've had other glitches. Those, as far as we can tell, have been cured and we're just waiting to get the car to a race and see what the results on the present setup will be . .

Thanx again to both CNCMotorsport and Hammertime . . serious discussion with factual info . .
Not sure how far the 360 heads have been taken, but they are capable of making 950+ Horsepower on the 632.

Not sure where you want to be at for over all horsepower, but this will give you a basic idea of what you can look for.

Good luck
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Old 01-13-2012, 02:12 PM
  #22  
bbchevy
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Originally Posted by cncmotorsports
Originally Posted by roadkill2
Thanks Guys, we're just trying to see what our options are before getting froggy and buying this coming year's backup short block, which, will end up being next year's Bullet if all goes well this coming season . . As I said, I'm not closely familiar with Big Inch BBCs and the Boss was just getting his feet wet this last year . . We ask questions because we want the shortest learning curve available and it's a hell of a lot easier (and cheaper) to get answers from those of you who might have them, than to learn them the hard way . .

Not that we're lost, as we've been in the money twice last year . . We just wanna do it as easily as possible . . Hell, I'm an old guy, I'm tired of climbing mountains and fighting thunderstorms . . There's a bunch of know how here and I'd love to share what I've learned about other classes of drag racing with guys who're successful in the brackets . .

Bracket racing is a whole hell of a lot different than either heads up or index racing . . But most of you know that . .

On the Headwork, they've been massaged by Steve Schmidt (former Pro Stocker and engine builder) and are all CNC . . At this point the heads aren't close to their potential, I believe, as we've had other glitches. Those, as far as we can tell, have been cured and we're just waiting to get the car to a race and see what the results on the present setup will be . .

Thanx again to both CNCMotorsport and Hammertime . . serious discussion with factual info . .
Not sure how far the 360 heads have been taken, but they are capable of making 950+ Horsepower on the 632.

Not sure where you want to be at for over all horsepower, but this will give you a basic idea of what you can look for.

Good luck
This Kind of Gives me a bit of Info?
I have a 634 that little by little I'm peicing back together?Had a few Main bearings Spin,so I ended yup with it?
Callies Ultra Crank& Rods,2-Sets of Pistons,set of 18*,and a set of 23*,and Just figured I put my Dart CNC Pro-1 355's on with the 23* pistons,and it will be 16.1,dont have a Cam,but would get something in the Range NEEDED?
Was REALY Hoping to make 1050??But,after reading the about post?You got me THINKING>?Although I know thw 355's are a Much better Flowing Head than the 360!
I'll just keep Plugging along and see what Happens,.............?
Later
G 8)
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Old 01-15-2012, 10:10 AM
  #23  
roadkill2
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Originally Posted by cncmotorsports

Not sure how far the 360 heads have been taken, but they are capable of making 950+ Horsepower on the 632.

Not sure where you want to be at for over all horsepower, but this will give you a basic idea of what you can look for.

Good luck
Thanx again . . As far as horsepower ratings, real or imagined, go, neither I nor the Boss are particularily concerned about them. That's a subject you BS about at the bar . .

Bottom of the timeslip is the intent for all the money being spent and questions being asked/answered. We're just looking to get consistent 9.50s (or close) at 4800-5000 feet . . and when we get to that point, then we'll try to step up. That's the reason for the 632 (or whatever we end up with) We've run high 9.80s with a tired 468, so 9.50s are a relatively reachable goal . . a little at a time . . .

We do use mathematical formula to establish a HP rating for each run, from the 60' time, the ET and quartermile MPH, but it's expressly for data base and not necessarily for bench racing . . Just another set of numbers to look at and compare actuals (Leakdown, Trans pressure, etc) to . .

The more data you have on hand, the better the decisions you can make both on race day and in the shop . . .
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Old 03-06-2012, 06:56 AM
  #24  
Pwmax
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What I gather, is, they are Dart 360's, that were ported by Steve Shmidt. Meaning, they are likely MUCH larger than 360. Likely 380ish cc+? Dart 360's with what I would consider fairly basic porting, meaning, not moving anything, just grinding metal out, with a larger intake, say 2.350, will make easily over 1000 hp.

As far as compression, due to the altitude, as much as possible. 15:1+, which, is fairly easy to achieve in a 632. The one thing I wouldn't do, is use a mega huge dome to just achieve a number. I would mill the heads and use a moderate dome, vs a huge dome, and more chamber. The engine will make more power at say 15:1 than to 16:1 with the huge dome. There is also a point of diminishing returns on cr.

Frank
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Old 03-09-2012, 07:11 AM
  #25  
roadkill2
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Thanx . . . Good to know . . . Appreciate it . . .
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Old 03-10-2012, 12:42 PM
  #26  
sbu
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Default Re: compression

Originally Posted by bear4333
what's the best compession ratio for a bbc 632 that would make the best power? I'm looking to purchase a short block, my heads are dart 360 cnc.
First are you ever going to run any power adders. if not, how often do who want to go into the motor, With nos we run 118 or even 123 and limit our c ratio to 14.2 If a straight motor deal would can go up to 16.5 to 17.1 but you will have to watch the timing, Now in bad air, or high altitudes you can run more timing, but if you are just going to bracket race, then build it with 14.5 and just have fun. Q-8 stuff is a whole different process, and your cost in the end will be higher. At 14.5 you can always add nos, now don't get me wrong you can add nos to about any motor, but nos works better at a lower CR, this is what we have found out on the motors we have and we do have 486 cubic smallblocks and three BB over 800 inches, and I do build motors for a living even though I'm retired. Hope this Helps
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Old 04-08-2012, 09:34 AM
  #27  
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Default Results . . .

OK, just to let you contributors know how and what. Yesterday, at Bandimere Raceways, in 7600' air, 49 and one of the first down the track, the 496 ran a 9.843, 139+, 1.44 60' . . . with a little wheelspin. (we were screwing with the wheelie bars) . .

Track and air went away from there, But the next three corresponding trips were, 9.849, 9.859 and a 9.915 with hard tire spin out past the tree . . Not to mention 9600' air . . And . . the MPH never got below 139 . . That's why we call it the "Grape Ape", it's an "Animal" on the top . .

Put it in the box and went home . . Couldn't ask for a better day than that!

Can't wait to see what it'll do with a little good air . . !

Thanks for all the help and conversation, you guys are great!

Happy Easter!

From Bear4333 and crew (Roadkill2, the crewchief)
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