The Stovebolt Site Forums The Shop Area The HiPo Shop ZZ4 Crate motor

Thought about posting in Engine Forum but that area seems to be about stock type engines. So, here goes, my 350/355hp ZZ4 is equipped with an Edlebrock 4bbl carb. Sorry guys I don't have a clue what size. The engine starts fine but obviously runs rich for a minute or so until with a slight amount of throttle it smooths out. That is unless you attempt to put it in drive, at which time it dies. Then it is very hard to restart. When it does re-fire you have to hold a slight pressure on the accelerator until the temp gauge starts to climb into the normal range, then it will idle normally and you can drive it. While driving if you stomp it it has a bad hesitation and bogs really bad. Any suggestions from you old hot-rodders? I have added a 1 inch spacer plate under the carb replacing the 3/4 inch that was on it when I got it. I have adjusted the air/fuel screws until I'm blue in the face. Driving me further over the edge! Help, please!

Sounds like you have a bad vacuum leak. Are the gaskets under the carb & spacers good & cover all the openings? I don't know what the cam specks on that engine are but they probably are pretty strong. You will need to run more timing & hook the vacuum advance up to a full vacuum outlet. You may need to get an adjustable vacuum advance & set it for low vacuum. Check the float levels & set them a little high if necessary.

electric choke also. either out of adjustment or need replacing

daren

Post the numbers stamped on the front of the carb and someone will tell you what size it is.

Vacuum advance was one area I was suspecting. The electric choke seems to operate as it should. I have a feeling the float levels are plenty high but I will check and adjust as needed. I will post the carb #s when I get back to it. Thanks, gentlemen.

You might want to contact BC52 ( Boyd )'. he just went thru this with his ZZ4 install.

Thanks, britcon.

If you know someone who has a spare carb of a different brand (edelbrock, demon, even a rochester), bolt it on and see how it works. I'm not at all a fan of Edelbrock carbs, and at the least you'll find out if it's a carb issue or something else.

For those of you who might be interested in what was found, here goes.
The vac advance was hooked to a very weak outlet. We put a tee in the line to the brake booster and it began to work properly. The electric choke was set for a northern climate and wasn't pulling off fast enough. Once these two problems were corrected the engine starts and runs like new. Thanks for all your suggestions.

I'll get back to you on tuning an Edelbrock,but I don't have time today.One thing to try.Remove the vac advance ,just plug it off.Try driving it a bit.It didn't seem to be needed.Let me know if your model is a 1406

BC52, all is well now!

Good to hear,Martin