Thread: How do I change jets in a Holley 750 Double Pumper???

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Here's a pic of your metering block and bowl. First remove the fuel line to make it easier. You may have to get new gaskets. OEM's have a tendency to stick and tear. Follow the previouly mentioned catch can as you remove the bowl screws. It will pour out on the manifold as it drains.

....THANKS for the replys & pic's; Krizziee, R Pope, C9X, Nitrowarrior & Denny..... I'm going to order some jets & try it.

C9x, I'm going to change jets because my motor still runs to rich {I say "still" because the idle was set to rich before I adjusted it a bunch leaner. It's set 1/2 turn out on both sides}. I looked over my dyno sheets & noticed when they went from 70/82 jets to 71/83 that the HP went down {-3} as did the TQ {-.3 & peak 200 RPM's higher}. When they went bigger yet on the jets the HP & TQ went down even more. The 71/83 jets were the last dyno run & we were out of time so I guess that's why they didn't switch back to the smaller jets. So I figured I would switch back to the 70/82 jets. The plugs still show the motor running rich but not nearly as rich as before I leaned out the idle. Do you agree with me doing this??? Will it make that big of a difference in so far as leaning out the motor??? Oh, and THANKS for keeping an 'eye' on me & asking why I was changing jets!!! Oh I don't know what any of this means but there is some other dyno info I can give you; FHp Hp, ME%, FB 1b/hr, BSFC 1b/Hphr, CAT & WAT....
Yes, I've considered going to a different carb. I was thinking the Barry Grant 3 x 2 set up. One thing that's keeping me from this is I want more power from my motor & was considering a motor change. I don't want to put on a $2000+ carb set up & then still want to switch motors! The carb I have was on this motor 12 years ago & when I just recently had the motor rebuilt I also had the carb gone thru at The Carb Shop in LA. I told then to set it up for HP& not worry about gas mileage. MISTAKE!!! The motor puts out 20 HP more
than before but gets 5 MPG less than it did in a car that was heavier!

Denny, You have a good memory! yes, the power valve is what I need to adjust to take car of my car stumbling upon initial acceleration!!!

THANKS again everyone!!! Bill