Well I finally got the 383 started. took her for a drive and its got no power tires wouldnt spin and its got a steady popping out of the exhaust at idle and under acceleration and deceleration. The computer was professionally tunned with LT1 edit after I did the camshaft install a couple years back. I know it needs retuned but would just changing to a 383 and ported heads make the difference.

What I had in the engine: 236/242 @.608/.613 112 cam and all the valvetrain nesseccary to support it.

What I changed: 383 with 10.7:1 compression, added comp-R lifters, ported and polished stock castings, portmatched intake

The builder added an adjustable timing chain to the setup and he advanced the timing 2 degrees.
I still have the stock fuel setup for now but I will be getting some new injectors shortly.
I am going to check the fuel pressure tonight to see where its at. Should it still be around 42 psi for this setup?

 

Im not too familiar with the timing on these cars but it is my understand if you want to advance or retard the cam, you must have it ground into the cam. Setting the timing through the timing chain ruins the timing for the optispark. You may want to put the chain on with 0*.

 

I may give that a try. I forgot to add that I also did a OVC set up and a changed to a NGK TR6. Is it possibly because the plugs are too cold?

 

Dont' believe so, popping is usually back firing, sounds like a timing issue.

 

Not true............
The opti is driven off the cam w/ a dowel pin and if you retard/advance the cam the opti will be alined right with cam. Also I have a friend w/ a lt1 in his s-10 with cam 2 degrees advanced and runs 11's all day with a stock lt1 and cam.

Sounds like your opti is just taking a crap on you. My opti did the same thing when it started to go.

 

Ah ok, like I said it was my understanding, I read a few posts where people have stated this.

 

Ahhh, seems the PCM timing tables are the reason why:

http://web.camaross.com/forums/showt...+chain+advance

 

The opti was just replaced about 13k miles ago and worked fine up untill my last engine spun bearings. I don't know why it wouldnt work now.

 

Im pretty sure the thread I posted above is the reason. Only other thing I would try is adjusting the valves and be 100% sure they are lashed correctly.

 

So it seems that the tunning would make the difference for the 2 degrees then i guess? That or change it back to 0. It shouldnt be much of a deal to change it back to zero. He installed a kit from cloyes to just use a hex key to adjust it but its all behind the water pump and opti. I may just see if the tunning will fix it first.

 

had the loud popping/ back fire just as you discribe after an engine swap turned out to be two plug wires crossed on the opti by mistake

 

Good shot man. Always check the obvious first. I had numbers 3 and 7 mixed up. Runs great now. Thanks guys.