So just had my camaro's engine rebuilt.. stepped cam down a little and added forged flat top pistons and rods...new msd ignition, wires, plugs - the works. only old parts reused were the ps pump and alternator. Compression built at 10:1 with a 270 cam. Here's the problem - a stock 350 could out run it. For some reason, its just acting an a** and running at a 3rd of what it should. And it's not cheap parts- 850 bucks on pistons alone... edlebrock 750 carb with a 1" spacer. Only thing we can guess is it's not getting enough spark or its the stupid carb. lol. Dang pos edelbrock.
Thinking of doing away with the spacer and bolting the carb straight to the performer rpm intake. Anyone have any ideas? Also getting a vibration as if it's misfiring, however when in park and revving, its smooth as butter...under a load, doesnt have the NEAR the power it should and it's not smooth. Timing checked over and over - it's right where it should be. Anyone advice would be GREATLY appreciated. After dumping 3k into this motor, i'm a very diappointed and unhappy camper!

 

Assuming (yeah I know) you used a conventional type 400 external balance crank, you did use the 400 flywheel/flexplate and harmonic dampener? If that engine is out of balance, your rpm's will be limited. Also, make sure you are using the right timing tab for the dampener you're using. Not all sbc dampeners have the timing notch in the same place rotationally. A mis-match between the two, and your timing isn't where you think it is. Goes without saying, you should be running rings around a stock 350.

 

First I would check the plug wires to be sure all plug wires are in the right place. Then check if any wires are jumping spark under load. (check at night in the dark with motor in gear and bring up the rpm, if you see spark jumping you have your problem)

 

We made sure we used the correct flywheel/balancer..thinking it's GOT to be a spark issue. I did see after looking around last night that it's got a little bit of exposed wire where the power wire for the distributor has been added ( wires spliced together using those little yellow wire clamp things) and theres a bit of raw wire unprotected. Not sure if this is it, but we shall see! Will keep you guys updated!

 

An exposed wire isn't going to affect anything unless it's grounding out.
Ok, so you have the right flywheel and dampener. Do you have the right timing tab pointer? Is this an old used dampener where the outer ring may have spun free from the inner hub (it does happen)?
If it were me, and I had the slightest feeling that it might be a timing issue, I'd double check where your true TDC is by using one of these: Piston Stop Tool, if you don't know how to use it, just ask. Then, put timing tape on the dampener, using the appropriate one for your diameter.

 

On 400 cranks and 350 one piece seal crank will have a roll pin so when installing the flex plate it can only go on ONE way. This roll pin is so you install the flex plate correct. Wouldn't be the first time some one missed this on a crank that is after market or sent out to have some work done and some one pulled the pin and didn't reinstalled it.

 

69, We used a stop tool when putting it together. And we checked everything again. I was hoping that it was that exposed wire grounding out against the firewall it was leaning against, but no such luck. Still at it though and not giving up. We have techs who've been working at our chevy dealership for years scratching their heads. lol. It's not funny, but it kinda is (just trying to find humor in my time of frustration). We're not giving up on it tho. We figure more brains are better, so hopefully will get this thing figured out soon. Again, thanks for the help. I'll continue to keep you guys updated. And when we figure out exactly what this problem is, i'll be sure to share!

 

Any chance you could have been a tooth off when you installed the timing chain assembly?
And did you check to make sure your distributor/timing is advancing with the throttle?

 

well, we got it pulled back apart and couldnt believe what we found. Brand new set of 800.00 pistons' weight are off. Called Wiseco and told them and their response was "we're sorry, but it does happen from time to time". Number 7 Piston heavier than the rest, so theyre replacing the set and we're going to have it rebalanced and put it back together...looks like ill be out of my baby for awhile...

 

Well, an out of balance engine was what I first suspected, just not that way though. Sheesh!!