jr711

I recently rebuilt a 69 Olds 350 with # 5 heads .Almost stock rebuild,with the exception of a melling torque cam:lift .448/.472 dur 280/290, Edelbrock 4 barrel intake and a Holley Truck avenger 750cfm carb with 1in spacer.Is this too much carb for my engine? It idles smooth and runs decent , but burn alot of gas,and I constantly smell gas,and I think it should have more power. I have played for hours with the timing and mixture screws.

firefrost gold

You need to change the jets out. I had a edelbrock 750 on a 326 once I leaned it out and set up the metering rods and the acc pump it was much better on fuel and performance.
I had a friend who had a lifted ford with a 400 m in it and a holley on it I took it to a old timer who set up the carb for it because he was working I could not belive the differance that old man in a one car shop did to that truck in about 2 hours .

scubastever

i believe this is too much carb...but thats a really hot picture.

you could drop down to holley 600 / 650 with larger jetting to get better mileage and pick up .

Run to Rund

You need to "tune" the carb with proper jets. Check your vacuum at idle and be sure the power valve isn't fluttering open then or on easy cruising. Most Holleys 'in the old days" came with power valves that opened at 8.5 oor 6.5 " vacuum and a big cam would give only 2-4 inches at idle. They were dumping fuel all the time. the idea of a power valve or metering rod is to lean out the enginer under light throttle = high vacuum and give it the proper fuel for power under heavy throttle = low vacuum. This works with mild stock cams, but with a big cam, you may even be better off jetting for power and plugging the power valve.