My computer controlled Q-jet has a couple "dead" spots. Not to mention gummed up beyond hope. I wanna do the 600cfm Holley and HEI conversion. So besides intake carb and distributor, what do I need? Any power gains from this? Any snags that you ran into? Is the standard HEI any better than my separate HEI? Thanks AND DONT TELL ME TO GET A 350 CAUSE I HAVE ONE in the other car

Thanks

 

You don't need a new intake.

I forgot to check if you have an auto, but by doing this, the computer will no longer be used, and you'll have to take care of the TC lock up somehow.

 

Dang, I didn't think about that. Maybe just get a rebuilt computer controlled Q-jet until I rebuild the engine? It will help to give it a real tune up

plugs
cap n rotor
oil change
tranny fuid change
timing check

I have to drive this beast with 178K miles to Illinois for Thanksgiving and need to make sure she makes it there and back. It has a very mild backfire at idle.....don't know what it is.

PS Anyone you know of rebuild these Q-jets?

Z28Bama

 

Hmmm, I'd make sure you have the correct routing on the wires. I mixed mine up once, and had a quiet backfire at idle.

 

I had to unplug a couple connectors to change the passenger side valve cover gasket and adjust rockers. I broke off the single wire that plugs into the side of the carb. Into a circular type shaped device on the carb. I can't think of what it is off the top of my head. I tried my best to re-attach it, but the connector is so unique, I would have no idea where to get another one. What is that wire?

Z28Bama

 

I meant spark plug wires.

 

TC lockup can be taken care of by a switch. Not real hard to do. If your really wanting to do a conversion it wouldn't be hard at all. I would recommend swapping the manifold while your at it (this WILL get you a little performance). If the motors stock go with the edelbrock performer. Other than that there are no real performance gains to be had from switching. There are some on the boards (five7kid in particular) who seem to know more about Qjets if tuning is a problem for you. You might try PMing him. The wire you broke off might be what controls the jetting of the primaries.

 

Electric choke. Mine has the plastic broken off, too, I just stick it back on and it typically stays with just the metal to metal until I disturb it again.

Do the tuneup first. Most carb problems are caused by ignition. Advancing the base timing to about 6 degrees typically will improve throttle response dramaticly. Make sure the thermovac system (the stuff on the air cleaner snorkel) is working properly (closed when cold, open when warm), and the silver tube going from the snorkel to exhaust manifold is there and in good shape.

After all that, if it still has "issues", Jet Performance, Carb Shop do q-jet rebuilds. NAPA has rebuilt exchanges available, as do most parts store chains.

 

Thanks for all the help. I probably will check out the Carb shop, cause NAPA's probably aren't performance prepped. I would like one to have the "performance" rods in it and tricked out a little. So what should the base timing be (6)? Also the PCV filter and plug wires are pretty crappy so I guessing they are a major contributer here. I will do the tune-up soon!! Thanks

Z28Bama