what jets for my carb?

[nvrbdn]

i have a 650 holly that wasnt producing. it was suggested to get a 750 dp which i did. but the supposed rebuilt carb is leaking like crazy. so im figuring on rejetting the 650 so i can get the car to monster mopar. what jets am i to ask for to get more fuel flow? thanks.

[nvrbdn]

going today at 3;00 to see if the speed shop can help me out here.

[Budnicks]

going today at 3;00 to see if the speed shop can help me out here.

What jets are in it now ?? is it fat or lean ??, what size engine is it on 383ci or 440ci or bigger smaller, stroker ?? is it a double pumper or vacuum secondary Holley Carburetor ??, what camshaft is in the engine ??, what intake is on the engine ??, what ignition are you using &/or is it a hotter ignition that requires more fuel ??, what kind & size of fuel pump are you using ??, a 650cfm is on the small side for a big block, even the stock 383ci, good ballpark rule of thumb is 2/cfm per/cubic inch of displacement, for performance apps.... I would start with #72-80 jets depending on what camshaft, ignition, whether it has headers, what altitude your at etc., do you have a gauze type air cleaner element, like a K&N ?? {if not I would suggest using one, they flow way more air than a paper filter, that will effect the tune also}, the accelerator pumps, accel. pump cam & accel. pump discharge nozzles/squirter's may need to be changed also, float levels may need to be checked &/or changed after re-jetting also, buy the blue float bowl gaskets, they are reusable, I would start with a #31 discharger nozzle in the front & work from there, it may need to be jetted with larger jets because of the small carburetor 650cfm, to make up for size & flow, it can be made to work well, it will take some tuning & time... There is a great book "How to tune a Holley Carburetor" you can get from the Holley's web site or many other performance parts outlets, like Mancini Racing or maybe call the Holley tech line themselves

[nvrbdn]

wow, didnt know i needed so much info. im a 383/30 over put in a mild street mopar purple cam stock fuel pump. hedders, stock intake, flame thrower dist from petronix, w/coil  guess i will be better buying the rebuild kit for the 750 dp holly than to re jet the 650 holly.

[Budnicks]

wow, didnt know i needed so much info. im a 383/30 over put in a mild street mopar purple cam stock fuel pump. hedders, stock intake, flame thrower dist from petronix, w/coil  guess i will be better buying the rebuild kit for the 750 dp holly than to re jet the 650 holly.

I'm a little anal on my questions, I know, but you need to give allot of information, to get the proper help on tuning questions... The tuning stuff I mentioned could need to be looked at latter, even with the 750cfm also, if you want it to run the best, any style of carb Holley, Edelbrock/Carter Thermoquad etc., will require some tuning with the performance parts you have installed... Good luck, call me if you need to...

[nvrbdn]

thanks, i may give you a call. thanks for the input.

[Budnicks]

thanks, i may give you a call. thanks for the input.

  Good luck, have fun...