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Author Topic:   holley jets????
bone30
Dirt Full Roller

Total posts: 32
posted May 02, 2004 07:33 PM  
anyone gotta baseline jet sizes for a 750 holley?? weve got 70's in the primarys and 83's in the secondarys and it seems to run rich when i open the secondarys

Racer X
Dirt Freak

Total posts: 256
posted May 02, 2004 08:47 PM  
Gas carb? What do the plugs look like.What is the engine combo? What is the timeing set at? A 70 in the front and an 83 in the back sounds like too big a split.Try like a 78 in the front and an 80 in the back or even them up with a pair of 80's.Run it an do a plug check.It's better to start off a little fat and work your way down than to be lean and burn a piston.

pacman #29
Dirt Full Roller

Total posts: 29
posted May 02, 2004 10:52 PM  
An older 750 with a powervalve in the front only will have about 10 jet sizes difference front to rear. If it seems lazy when you get into the secondaries, and the plugs look rich try 80's with the 70's and see what the plugs look like. Watch the temperature! Cool nights like 2-3 jet sizes larger than warm ones.

bone30
Dirt Full Roller

Total posts: 32
posted May 03, 2004 05:14 AM  
355 flattop, .480 cam, dart ie heads, runnin bout 6300-6600 plugs look fairly dark. gas, doesnt seem to load up till i open the secondarys. actually lets out some black fuel smoke at full throttle

MOD75D
Dirt Freak

Total posts: 236
posted May 03, 2004 08:21 PM  
I agree with racerx. Ihave never ran more than 4 steps difference in jet sizes. Try the 78 and 80 and see what she does.

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