Over the winter I did a bunch of upgrades on my ‘71 Big Block: converted from the TH400 to a Tremec TKX 5 speed, aluminum radiator with a Spal electric fan, and a 140amp alternator to run it all. Car was overheating at first but I got that worked out, now it stays cool and runs great. That is until I’ve been driving for a bit, then when I push in the clutch or put in neutral it just dies, no sputter it’s almost like the key was turned off. If I hit the gas it’ll keep running, let off and it will idle for 30 sec or so and then just die. Every time it dies I can turn the key and it immediately restarts, don’t even have to touch the gas pedal. Adjusting the idle doesn’t make much of a difference.

I have an HEI in it so I tried swapping the ignition module in case that was starting to act up, no difference. This came on all the sudden after I’d finished all the upgrades so I’m a bit stumped. Any thoughts? Carb (Edelbrock version of quadrajet) was rebuilt about 10 years ago. Definitely not vapor lock because I had that issue before and it would stumble first (I ran an electric Holley pump and return from near the carb to solve that problem).

Thanks,
Paco

 

What is your timing set to?
Is your vacuum advance connected?

 

I haven’t rechecked it but it was 15 deg initial and 35 all in when I set it a while back. The vacuum advance is connected to the carb, I’m going to try connecting it directly to the manifold vacuum to see if that makes an improvement.

 

So connecting direct to manifold vacuum made a big difference, and I blocked off the line to the headlights/wiper door to rule out vacuum leaks. It’ll idle fine around 900 rpm but below that and it’ll intermittently stall. I’ll have to reset the timing tomorrow and see but I’m getting closer!

 

Sometimes that's all it is! Good luck, and thanks for updating as you resolve the issue!

 

Thanks - I’ll post back if I’m still having issues after setting the timing.

 

Sounds like you are on the right track

 

Adjusted the timing and I’ve got a solid idle around 750rpm, any lower and it dies. Works for me!