I have just completed my engine rebuild and have a couple of carb questions. First a little about the engine The engine is a 390 .060" over, edelbrock performer intake, edelbrock 750 performer carb, headers, dual exhaust, and comp 268H cam. The engine seems to run great, except for the low end. The idling seems to be fairly smooth. Mid and top end the carb seems pretty responsive. The problem I am having is when I initially step on the gas from idle the engine seems to bog. Then if I pump the gas a couple of times it gets going, once the rpms are up over 1000-1200 is works great. I tried to adjust the accelerator pump, it is now at the highest setting. That did help some but it still bogs a little. Not sure what to do as previously I had basically the same build only I had a stock cam and it ran great. Seems like now I am too lean at the low end. Anyone have any ideas?

 

Sorry forgot to add that currently my carb is all stock. The part number is edel 1411.

 

Also to note. The engine is set at about 11 initial advance for the timing and I am using the timed port on the carb for the vacuum advance.

 

Follow link,

http://www.edelbrock.com/automotive_new/mc/carbs_acc/carbs_access_main.shtml

Download manual, READ,(that's an important one), adjust, have fun!!!! It's that easy. Excellent description of carb and all it's functions, and hands down easiest step by step set up/adj proceedure ever.. Only catch, you gotta do it all.. Good News---- takes little time and is, WELL WORTH IT !!! Good luck, hope this helps.

 

The tuning specs for Edelbrock 750's is here: >>> http://www.sacinvest.net/ford/ford_docs.htm

Actually, I think you might have too much CFM for a 390. For mild street use, Edelbrock recommends a 600 cfm for engines from 283 to 400 cid, not 750 cfm. You might be sucking too much air at low RPM and it's effecting your response.

Hope this helps.

 

Figured out part of my problem. 1st the carb was way too lean. This helped a little. Second I have a problem with the timing. I set the timing to 20 degrees and it helped dramatically. Now I just have to figure out if my mechanical advance is working properly or my harmonic balancer is just way off.