Jet size - 750 dp For 383, Headers, single plane intake, stock 906's

[ripntear]

Old hemi grind purple shaft cam. 38 degrees total timing. Whats a good starting point with jets. My 750 is brand new but its lacking top end and I know its the jets, so before I just jump to upper 80's I thought I'd see what others have found best before I waste my time. I know I could run a 850, mopar mag. ran a 930 but I'd like to see what I can do with my 750 . Appreciate your thoughts. I'm out for HP not drivability.

[dodge freak]

Its very hard to say, what you need is holley quick change fuel bowls, I have them its great, just take two screws off and use the jet tool to remove the jets. You might drop a few at first but if you can leave a few in it cause the bowls is deeper for that reason. On the holley hp its should be jetted from the factory at 72-73 primary with a .060 power valve hole-not power valve opening that when its open, the .060 is how much fuel comes out when the valve is open and 84 jets for the secondary. Try that and then keep going up till it slows down, the 84 might be to rich but I don't think so. Also the gas matters, depending on where you live. I think you might have just a 750, so those jet sizes might not be right, try a 83 in back and the front if it feels good, no leanest leave alone for now. Keep going up in back till its to rich, then once you know what it likes go down 2 or 3 jets in back and go up in front to see if its better. Problem you might run in to it might get so fast its hard to tell what the best, but it takes time to find out. Hope this helps-get those quick change bowls, you like them-no gaskets to worry about.

[firefighter3931]

Have you looked at the plugs ? If it's lean the plugs will show you by being white/light grey. A 750dp should be plenty for a mild 383 ci combo. Check your float levels. Make sure your fuel pump isn't weak, fuel filter clogged etc...

Check your fuel pressure as well. Make sure the throttle linkage is set up correctly and the secondaries are fully open at wide open throttle.

Just some ideas to look at before you rip into the carb.


Ron

[dodge freak]

  Forgot about all that, make sure the throttle is open all the way, happens all the time.

[Todd Wilson]

Forgot about all that, make sure the throttle is open all the way, happens all the time.

A solid lift 318 cam will help too!


Todd

[dodge freak]

Are your valve springs good or are they worn out stock ones? Lifters that are pump up will stop the motor from revving no matter how big the carb.