q-jet craps out on hard accel 1-2 shift

[hillytim69]

Been driving my work in progress 75 shortbed and find it falls flat on its face right when upshifting into 2nd during hard accel. Have to let up on it for a second then it will straighten out. Also noticed this same condition when laying rubber and the rpms get up there. It is a mild 383, 480 lift Elgin cam, street ported World S/R 1.94 heads. Supposed to be 9.8:1 comp with these heads. Running Performer RPM Q-jet intake and a stock Edelbrock Q-jet carb with divorced choke for late 70's trucks. rear end is either 3.73 or 4.10 I'm guessing.Trans is a th-350 with shift kit so 1-2 shift is real hard. Had this carb on an old c20 with a pretty stock 350 and it ran great. I can say on this 383 it feels like it wants to pull hard when going into 2nd then it falls flat. Wonder if you guys think it's a carb issue or possibly ignition. . It runs pretty good otherwise during normal driving. I don't know much about tuning carbs. I do have a low mile Carter AFB 600 9605 manual choke thats been sitting for 10 yrs. I'd put a kit in it and try it but doubt it will be enough carb for this engine anyway. Also if any of you guys have any opinions on my whole combo fire away. I know these heads may not be the best for this engine but I had to run what I got. I don't think I'm happy with my cam choice either but can always change later if I feel the need. I thought the qjet was the way to go but now not so sure, I'm thinking about a 670 Avenger... At least its running and I know I'll be driving it to the Car Craft Summer Nats this July rather than shamefully driving the Civic!

[longbedrick]

my old man and I just went through something similar. 396 BBC with a Muncie 4-speed. everytime we'd get the RPMs above 3500, the engine would sputter, but not die. figured it was the ignition. so we rebuilt the HEI unit with new module, coil, plugs, wires, etc. fired her back up, took her for a test drive. same deal. so we figured it was a fuel problem. found a Torker 2 Edelbrock on Craigslist for $50, and stole the Edelbrock 1406 600cfm carb from another project. BAM-O! back in business

[hillytim69]

This is embarrasing but I owe it to tell the truth. I checked the throttle cable out and it was hooked up to the hole in throttle linkage that allowed just not quite enough travel on this truck. Same carb in my Dads old 79 C20 and no problem but for some reason its just a little different in my vehicle. I changed it to the other hole on the linkage and it now has full travel and went for a test drive and the truck freakin' rips! Love that q-jet surge when the secondaries open. Pulls hard all the way to 6 grand. I love it.

[Restrorob]

It's hard to beat a properly set up Q-Jet....

[Driveway Dreams]

Wow, I wish I could see 6 grand in my truck. It wont even pull past 3 under load. Glad to hear you found the problem.