[Commissar]

Hey everyone, I have a recently new to me 68 GTO that I bought and have been tinkering with now trying to get it right. The Engine is a 400 bored 0.030" over and sounds to be running strong attached to a TH400 his/hers hurst shifter.

My problem is when I am at WOT the shifts are very slow, like the car takes a few seconds to figure out what gear to go into (RPM according to hood tach is around 4-4500 when it starts thinking about shifting). Normal driving it shifts fine. Where do I start trying to troubleshoot this? When it does shift it shifts hard. I believe there is an 1800 stall in there. What is some other information that you all need to help me figure this out.

I have some other issues that I need to address as far as timing and carb setup, but those will be a different thread.

[65 Lamnas]

Originally Posted by Commissar

Hey everyone, I have a recently new to me 68 GTO that I bought and have been tinkering with now trying to get it right. The Engine is a 400 bored 0.030" over and sounds to be running strong attached to a TH400 his/hers hurst shifter.

My problem is when I am at WOT the shifts are very slow, like the car takes a few seconds to figure out what gear to go into (RPM according to hood tach is around 4-4500 when it starts thinking about shifting). Normal driving it shifts fine. Where do I start trying to troubleshoot this? When it does shift it shifts hard. I believe there is an 1800 stall in there. What is some other information that you all need to help me figure this out.

I have some other issues that I need to address as far as timing and carb setup, but those will be a different thread.

I'd start with a gauge and monitor your pressures. Sounds like a leak.

[Commissar]

Originally Posted by 65 Lamnas

I'd start with a gauge and monitor your pressures. Sounds like a leak.

Where should I monitor from and what would I be looking for? I am pretty sure I can hear a vacuum leak under the hood, but havent been able to pintpoint it yet.

[gtohurstjudge]

Fix your vacuum leak.....you have poor vacuum to the vacuum modulator on the right side
of the transmission. That could be causing your problem.