here is my question, does this sound like it should be a descent combination for some power.
in my 74vette i have...a gmpp 350 short block,
edelbrock performer rpm cam
gmpp vortec heads
edelbrock performer rpm air gap
holley 600 street avenger carb
crane blue full roller rocker arms
converted heads to screw in studs
hooker super comp long tube header going back to pair of flow master 40 series
B&M 2600 stall
rebuild 400 turbo
4.56 gears
i just picked this up from shop on friday after months of being their and i ask shouldnt this combination at least be able to break the rear tires loose? does not feel any more powerful then did before though i am now out 5k. unsure where to go from here the only items that reused of mine were the carb(basically new when i brought it in) and mr gasket 12s electic fuel pump. is this a lost cause or am i missing something obvious.

cam specs are
Basic Operating RPM Range 1,500-6,500
Intake Duration at 050 inch Lift 234
Exhaust Duration at 050 inch Lift 244
Duration at 050 inch Lift 234 int./244 exh.
Advertised Intake Duration 308
Advertised Exhaust Duration 318
Advertised Duration 308 int./318 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.488 in.

less then 500 miles on it so i gotta take it easy. but cruising at 50mph pulls almost 4500rpm. i know not good for a break in. but i did hammer it once off the line and got nothing would not even break back tires loose i figured with that 4.56 rear it shouldnt be a problem. trying to figure out where i went wrong on this engine i thought for once i did everything right.

 

The 600 cfm carb is a bit puny for your engine, but I'm suspecting that your secondaries on the carb are not opening or not opening fully. Have someone sit in the car and fully depress the accelerator pedal while you watch to see if the butterflys fully open. Also make certain that any secondary lockout/release mechanisms on the carb are functioning correctly. Your problem may be resolved as simply as making a throttle cable adjustment.

 

If You find the carb is working properly then check ignition timing. That car should be able to light the tires effortless.

 

That alot of advertised duration for 350 engine and what the compression?? What the lobe sep on that cam?

 

the carb is vacum secondaries should they still open when not running. i fully and wholeheartadly admit when i dont know something which is why i took this to a professional to build.

 

Well, in essence, the vacuum operated secondaries is a "lockout". If that isn't working [properly], you won't have any power. Since you have a Holley carb, someone more familiar will have to advise you on how to check for full throttle opening.

 

Ditto on the secondaries. When I got my 72 it was a dog. After looking it over it was the throttle cable being hooked into the wrong linkage slot on the carb, preventing the secondaries from opening. Now, she will smoke the tires as long as you want to and thats with a stock engine.

 

If that's the 8.5 compression ratio motor with a 234 int./244 exh @ .050" cam then you have parts mismatch and your DCR would be off the scale on the low side and probably the reason you can't lay rubber with tractor gears in the back Only people that rode the short bus to school would put a motor together like that and charge you to put it in your car .

You will also have a problem if you "baby" it for 500 miles because the rings will not seat properly and you could have a oil consumption problem, do a search on seating the rings or breaking in a new motor.

 

Could be a timing issue. Are you using the original distributor? Did you make any changes to the iginition timing during the process? What did the shop say when you talked to them about it?

 

Everything i can find says to take it easy and baby it for first 500 miles do not go over 60 do not hold speed for any length of time vary rpms often. This cam and intake combo was the edelbrock performer rpm power pack combo. these parts were all matched from edelbrock i didnt have the extra 1400 for the edelbrock heads but edelbrock told me the gmpp vortec iron would work if i used their springs which i did. we have an 8th mile track here and that is the reason for 4.56's.

 

The people at the shop did at lot for me and i dont want them to feel like im complaing or anything so i wanted to try to figure on my own first. the distributor has been replaced with pertronix hei upgrade.

 

THANK YOU!!!! After reading this thread. I decided to go out into the garage and check my secondarys. I opened the throttle all the way and the secondarys remained closed! I then tried to open them up by hand. They would not budge. So I thought maybe somthing is blocking them from underneath, stopping them from opening. Because I tried to push down on them with my fingers thru the carb opening. and still nothing. I took my carb off the intake. As I checked it out, I noticed the "secondary lockout" was not working. When the accelorator is pressed full open, the secondary stays put stopping them from opening. The push bar that is suppose to push it to allow the sceondarys to open was to where near even touching the lockout. It just swiviled there by gravity stopping any further movement of the secondarys. After looking in the manuels and trying to figure out how to adjust it, I come to the conclusion that the chock vacum that is also attached to the shaft to the bar to open the lockout is way out of wack. Nothing lines up where it should. So I zip tied the lockout to the open position. Otherwise gravity just lets it hang closed. I then pressed the accelerator full open and wahlaa. She's opening up at full throttle now. Can't wait to take it out tomm. and see the difference.!!!

 

Well, she is a he now. She's got ball's.! What a difference. The engine just wakes up now. Can break the rear wheels now. Thanks....

 

The problem that Motorhead is refering to is that the Edelbrock combo really needs a 10:1 compression to work well. The GM short blocks need 58cc head to get 10:1 compression. Depending on the size of the heads, you could easily be at 8.5:1 compression. Then, the engine runs like a dog.

 

I have close to the same came specs @50 and total lift. I built mine and it has late model D port heads with a total comp of 10.25-1 . It also has Edelbrock 600cfm. With 3.55 gears and a 2600 stall, 255-60-15 on it . When I floor it I have to do some counter steering.:

 

you must run at least 10-10.5 -1 compression with that cam...jmo....

 

Well....the poster hasn't been back since he zip tied the carb lockout to the open position. Hope he has brakes...

 

Im here. Just because I opened the secondarys doesn't mean Im beating on my car.

 

Friends 82, my 77, and working on the 71. Don't need to lock the secondarys on that one!

 

You got all that above for 5 grand? They definitely cut some corners.