Jcro

I don’t know what you mean by changing the vacuum secondary to ported vacuum I don’t believe I did how would I do that. I don’t see any kind of vaccine line going to the diaphram on the side of the carb and I sprayed down all of the adapters and intake and found no vacuum leaks. Yes this is the set up I bought it with

What size should I have in it

I’m having an issue where my GTO runs great in park. But when I put it in drive it idles much lower and stumbles like it’s going to stall and if I give it any gas it stalls out. This is my first classic and I’ve never worked with carbs until this car. So I’m assuming it’s a tuning issue. But I might have something hooked up wrong or possible vacuum issue but I sprayed the engine down with throttle cleaner and found no vacuum leaks. If you can see anything hooked up wrong or tell me what I should mess with it would be much appreciated

so I had the vacuum advance on manifold vac not ported and had a leak at the ported vacuume port on my rear carb so I switched the vac advance to ported and plugged the vac leak on the rear carb. Once again it runs awesome while it’s in park it reveals up really nice and idles well but when I put it into gear it starts running real rugh and idles about 200 rpm lower. Since I’m new to carborators I’m guessing it’s an issue with some kind of adjustment? What should I mess with and why does it run great in park and neutral but try to stall in gear

Okay thank you both I’ll check it all out in the daylight tomorrow. If you think of anything else I should check just let me know 👍

I don’t have a manifold vacuum port so should I ditch the pcv valve and just put a breather in it’s place? I don’t understand what deduct the initial means? Sorry this is my first classic never felt with carbs before.

I set the timing to 16 degrees and then hooked up the vaccum advance. Would that be the correct thing to do? The carbs have stock sizes for the accelerator pump/ power valve however the jets are 55 instead of 60. On my rear carb I ran a vacuum line to a PCV valve on my passenger valve cover, could that cause an issue? Also could it be a spak plug gap issue?

Hi I’m new here, I’ve been sitting parking on a 1974 Pontiac GTO for about a year. I got it running for the first time in about six months yesterday after I rebuilt my carbs. I have two Holley 600 on a tunnel ram intake. I also replaced my point distributor with an HEI. The engine I have in the car is a 1975 firebird 400. The issue I’m running into is the car idles great but when I give it about half throttle it bogs down and stumbles like it’s gonna die but when I take my foot off the gas it reeves back up to the proper RPM and idles fine. Any advise? I assume it’s something amiss with my ignition system or my carbs.