How big of a carb????

[whitey70ss]

Hi I'm new to racing junk and am putting together a 70 chevelle with a smallblock and a muncie with 3.73 gears. The specs on the engine are (350 .60 over, edelbrock performer RPM heads, isky cam 505 lift 292 duration, 244 duration at .050. It has good headers,free flowing exhaust. I ran this combo with a 600 edelbrock carb and have been thinking of switching to a holley. I feel that the quadrajunk style carb is holding it back?? Any and all info is appreciated! THANKS WHITEY.

[Tod74]

650 or 750

[whitey70ss]

That really doesnt answer my question todd. I was looking at both 650 and 750. Which one will work best for my setup??

[chrisr]

I had a 72 Chevelle with a 355 that had about the same setup and I ran a 750 dp with the jets that came in it and it worked great. My cam was a little bigger but only like 520 lift with a 302 duration(somewhere in that range). I also drove mine alot on the street and never had any problems loading up.

[Tod74]

That really doesnt answer my question todd. I was looking at both 650 and 750. Which one will work best for my setup??

If it's a street car I would go with the 650. It will be more responsive and fun to drive. I had a 400 with a cam very similar and I went from a 750 to a 650 and it was way more peppy to drive,.

[whitey70ss]

Ok thats the info Im looking for. If I go with A 750 cant I jet it down a little to get that responsivness??

[chrisr]

IMO if you go from a 750 to a 650 and it makes it more peppy than the 750 was just to much. Since it worked for TOD it may work for you. I had tried a 650 on mine and the 750 was alot more responsive. It all depends on what your engine likes. If you have access(friends etc) to one of each, try them and see which one works better. I may have had more compression and more flow than what you have.

By the way TOD, I like the avatar.

[Tod74]

IMO if you go from a 750 to a 650 and it makes it more peppy than the 750 was just to much. Since it worked for TOD it may work for you. I had tried a 650 on mine and the 750 was alot more responsive. It all depends on what your engine likes. If you have access(friends etc) to one of each, try them and see which one works better. I may have had more compression and more flow than what you have.

By the way TOD, I like the avatar.

WHAT HE SAID . Always better to test before you buy if you can.

And yes the reason the 650 was better for me was the 750 was just too big.It was a 9:1 motor and the 750nhad the 50 cc pump on the rear and it just would fall on it's face when you floored it...the 650 brought it to life.

[jmarksdragster]

A 750 vacuum would work great, best of both worlds. Responsive and you can tune the opening rate of the secondaries to suit the engines needs.

[bobby36]

i have 358 14.5-1 motor heads flow 230 cfm started with 750 went 7.53 with a 1,59 60 ft then put a 650 on it went 7.17 with a 1.46 60 ft and i dont understand that unless my 750 was not right

[bowhay]

i think a holley 670 would suit u just fine

but a 700 would also work

[whitey70ss]

I CALLED EDELBROCK TECH LINE TODAY i TALKED WITH ONE OF THE TECH GUYS HE TOLD ME THE PERFORMER INTAKE WAS LOSING POWER HE SAID I SHOULD HAVE AT LEAST A PERFORMER RPM OR IF I DONT MIND LOSING A LITTLE BOTTOM END TQ GO WITH A VICTOR. HE RECOMENDED A THUNDER SERIES CARB IN 800CFM?? DOES THIS SOUND RIGHT?? HE SAID WITH THAT COMBO AND MY CAM I SHOULD BE IN THE 430-440 HP RANGE?? DOES THAT SOUND RIGHT OR IS THIS GUY JUST OVER RATING HIS PARTS?? :roll:

[cncmotorsports]

AED 650 Holley

http://www.cnc-motorsports.com/product.asp?ProdID=7757&CtgID=

You will be very happy with the performance.

This is what i would use for you application.

[whitey70ss]

thanks for the info cncmotorsports I actually just got a 750 dp for cheap! would anyone go ahead and try this carb or should I sell it and get the 650dp?? Can I jet this 750 to work good for my combo?

[oldandtired]

Smaller is always better. You have higher velocity and the carb is working in it's "center range".
I remember being young trying to imporss everone by having huge carbs on the street. I ended up using both feet to keep it running!! Anyone else learned the hard way??

[cepx111]

i have 358 14.5-1 motor heads flow 230 cfm started with 750 went 7.53 with a 1,59 60 ft then put a 650 on it went 7.17 with a 1.46 60 ft and i dont understand that unless my 750 was not right

I'm thinking the 750 wasn't right.
Thats a pretty healthy sounding motor and they usually love more air and fuel.
JMO> Cp

[cepx111]

Hi I'm new to racing junk and am putting together a 70 chevelle with a smallblock and a muncie with 3.73 gears. The specs on the engine are (350 .60 over, edelbrock performer RPM heads, isky cam 505 lift 292 duration, 244 duration at .050. It has good headers,free flowing exhaust. I ran this combo with a 600 edelbrock carb and have been thinking of switching to a holley. I feel that the quadrajunk style carb is holding it back?? Any and all info is appreciated! THANKS WHITEY.
I'd say yes, that 600cfm hunkajunk performer has to be holding you back,they make great boat anchors though.


I put a mild pump gas 351W in the boys 89 GT mustang, similar set- up as yours, performer heads and intake, 500 something lift hydralic cam, shorty headers, flows, 373's, msd 6al box.
We're runnnig a 750 double pumper W/ 30cc acellerator pumps front and rear, 78 square on the jetting (no power valve) and a pro-form center section.

Best ET so far - 7.50 in a tad short 1/8 >
not bad for a ford I thought.


Goodluck, Cp

[dragonmaster093]

ive got a simular motor but only 8.5 compressionported and polished heads edelbrock performer intake 1inch spacer and accel cap rotor wires (motor was a dirt track imca sport mod motor) has 600 holley but for some reason i dont seem to make any real torque its in a 77 monte carlo with th350 and 2000 b&m torque master converter any ideas dont have headers yet

[cepx111]

ive got a simular motor but only 8.5 compressionported and polished heads edelbrock performer intake 1inch spacer and accel cap rotor wires (motor was a dirt track imca sport mod motor) has 600 holley but for some reason i dont seem to make any real torque its in a 77 monte carlo with th350 and 2000 b&m torque master converter any ideas dont have headers yet
Wow 77 monte, them things are tuna boats, it's gonna take alot of torque to get that thing moving.
Whats your timing set at?

If it was a dirt car motor, chances are the cam is a high winding piece, you might need to swap it out for a cam more suitable to your needs.
Also what rear gearing do you have?
Cp

[dragonmaster093]

gears stock cam real ruff idle 32 degrees i know it has torque and power dog off line but will haul ass

[dragonmaster093]

old 305 had more power hell with same intake carb ignition on half drad 305 could boil hides not now has 255 75 15s on rear

[Tod74]

gears stock cam real ruff idle 32 degrees i know it has torque and power dog off line but will haul ass

I would Bump the timing up to 36-38 deg.

[dragonmaster093]

ill try that

[kbartley]

Whitey, did you get youre carb situation straight? Kris

[justin45]

go with a 700 holley

[whitey70ss]

Thanks for askin kris! I just got my oil leaks fixed and decided to put the victor jr intake on and a 750 dp . I havent got to tune the carb yet nor do I know enough about these double pumpers to mess with it. But for just throwing it on and setting the Idle it works very good. I have a slight dead spot just off idle but I dont know where to start looking.

[kbartley]

Check youre timing first. Get a vacuum gauge hook it to a full vac. port, set the mixture at idle looking at the gauge. Try it out, if that dont get it then its time to adjust the accelerator pump, NOT TOO MUCH AT ONE TIME. What type of distributer are you using? Keep us posted.

Kris

[whitey70ss]

msd pro billet distributor. When you say adjust the mixture per the gauge. What exactly am I looking for??

[cepx111]

Adjust the idle mixture screws (the small ones on the metering block) to achieve the highest vacuum.

Bump your timing up to at least 38

Getting some taller gears would be a big help too.

[whitey70ss]

I have a vacuum brake bleeder with a gauge on it will this work?? As for the gears I want this to be a little more cruise friendly I have a nova with 4:11's and 25 in. tire not real cruise friendly. :lol: This chevelle has 3:73's and 26in. tire, seems to work well for all the more I've driven it.