[Blownmope]

My buddies olds, 455 mild build, turbo 350 trans stock convertor, 3:55 rear gear, motor lays down between shifts, any ideas as to what causes this?

 

[Horndog]

Weak valve springs or running out of fuel.

 

[Bad78Cutlass]

Maybe need jet extenders?

 

[Bammer540]

stock converter. You shift and it pulls back to the stock stall speed, probable 1500 at best.

 

[Blownmope]

stock converter. You shift and it pulls back to the stock stall speed, probable 1500 at best.

That is what I thought, need to check the fuel system too, I told him to get ahold of ptc and see what they recommend. Thanks for all the input.

 

[gat]

needs more gear?

 

[Uncle Paul]

How is it if you short shift 500 to 1000 RPM's lower?

 

[MattG]

No idea if this could but your buddy's problem but I just battled a year long problem of randomly losing 3000-4500 of RPM on each shift. If I replaced the plugs after every 2-3 runs, it would not happen.

After replacing almost everything in the ignition and electrical system, it turned out to be the intake gaskets were sucked slightly into the ports on 2 or 3 cylinders. It was causing a slight oil leak into the ports which was fouling the plugs. It was also causing a slight vacuum leak and also disturbing the flow of the air/fuel into the intake.