Holley 2 bbl jetting question

[Gene Fiore]

I am getting ready to install a Holley 7448 350cfm carb on a modifed log head ( 1.75int 1.50exh ) mild port, direct mount. This is in my Maverick with a stock 250 motor and auto trans. The only mods are dual out headers and FSP DUI dizzy. Any ideas as to where to start out with jet sizes. The carb has 64's in it right now. Oh, and the elevation hear in the Phoenix area is around 1200 feet. Thanks.

 

[CZLN6]

Howdy Gene:

I'd probably start with what's in it and assess from there. There are too many variables to accurately predict the perfect jet size. With a Holley, you'll probably spend more time working on the accelerator pump circuit and finding the right power valve.

Keep us posted on your progress.

Adios, David

 

[wsa111]

Gene, when i had the 7448 on my modified 200 i ran 59 main jets & the 8.5 power valve.
Using the innovate wideband A/F tester my cruising ratio was 14.5. Full power was about 12.7.
Using this combo should get you in the ballpark.
I switched over to the 4412-500 which required complete reworking of every area of the fuel delivery.
Some of the local roundy-roundy racers use the base from the 4412 on the 7448 because it has larger throttle bores. I never had a chance to test this deal out.
Our frenchtown flyer uses the larger bases on his 300" dragster.
Hope this helps, Bill