Holley Carb Jetting Question [Archive] - Chevelle Tech

: Holley Carb Jetting Question


Jeff
Aug 18th, 99, 4:35 PM
Hi All,

I have a '69 SS with the following combo:

396 C.I.
Oval port heads
Holley 750 dbl pumper
Performer Alum intake
Comp Cams 292H
Headers with Flowmaster 2.5" system
3.73 Rear End
4 speed

The car performs flawlessly except when I am cruising about 35-40 mph in 4th gear with the throttle barely cracked open. The engine will act like it is slightly starving for gas. If I press the accelerator down slightly farther, the problem goes away. The primary jets are what came with the carb, and the Holley catalog says they are size 71. Would increasing the primary jets a couple of sizes cure my problem?

Thanks!

Jeff

drptop70ss
Aug 18th, 99, 5:13 PM
try going up to 73 or 74s, sounds like you are on the edge with the 71s..I usally run around 74s with a mild 396.

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70 chevelle ss396 conv
66 chevelle ss396 hdp/conv

67RAT
Aug 18th, 99, 5:18 PM
jeff
go to #73 jetts on the primarys,see what comes of it,If then it seems rich,go to 72s.sounds like you need just a small bit more fuel while in the cruise mode.a power valve change may help ,but I wont get into that,post back with the results.good luck.67rat member #199

COPO
Aug 20th, 99, 2:00 PM
Try to richen the mixture screws a 1/4" out.

Mark