Rough running when started hot

[gmr714]

I have a 74 260z and it runs great until I stop for gas or a quick bite to eat. If I start it while hot it will run very weak and I have to choke it to get some power this problem continues for miles. If I let it cool down for 15 minutes it runs great again. I thought it was vapor in the lines but I insulated the best I could with raybestos tubing and header wrap where I could. Both fuel pumps are new and good, new fuel lines, filters, good gas, and carbs are adjusted correctly. It's annoying more than anything since it is good after I wait 15 minutes. I need some Ideas on what to try, please.

Thanks, Mark ( new old Z owner):cross-eye

[z74z90]

Most likely still "vapor lock". I have endured variations of the same for 34 years! I did install a "fuel injector fan" from the '79-'83 model years and it has helped considerably. I just have it on a toggle switch and turn it on during hot, humid weather. Bolts right on, no problem.