95 Chevy Truck, 383 Engine Swap Problems

[chevyk2500hd]

A year ago I took my stock 95 Chevy truck 350 and stroked it out to a 383. I upgraded to a 670cfm Holley throttle body to handle the extra flow and fuel. I have tried custom chips from both Jet and FAST. Neither company could get the engine running properly. My major problem is that the timing retards below 0 degress during shifts which causes fire to shoot from the intake. These timing retards are only during shifts at wide open throttle. If I don't smash the petal to the floor the timing doesn't retard so much that I have fire comes through the intake during shifts. Also the motor just doesn't want to accelerate very well. If you were wondering the vacuum seems to be good all the time. I am not throwing any check engine codes. I also use Datamaster logging software to watch all my engine parameters. I am up for any ideas that anyone may have for me.

 

[sweetk30]

i have seen some good info on www.tbichips.com

 

[retroblazer]

I used Howell for my chip, but I did it though my engine builder. It rips. His name is Dennis Chencharick at D & L Peformance in State College,PA pm me and I get his phone number. He'll set you straight.

 

[Eastcoast 4WD]

Is it possible that when you reinstalled the distributor it is one tooth out? It sounds like the timing is on the brink of too far retarded. It is possible it is one tooth out and then it got adjusted to compensate which woulden't throw any codes and make it run bad.

 

[chevyk2500hd]

The position of the distributor is not relevant. As long as the timing is set with a light ,the distributor will be turned to compensate for any position of the distributor teeth.

 

[85k30]

is the distributor you are using the newer style with the coil mounted on the intake manifold? is it a new distributor? if it is the one that has the coil mounted on the intake manifold. they have a pick up coil that tends to burnt up. when thay start to go they cuase timing problems at wide open throttle. i used to work at gm dealership and seen that problem several times and each time it was the pickup coil.