Holley 4492 stock jet size

[earntaz]

I have looked through a half dozen Holley books I have and not a one indicates what the stock jetting was on the 70' LS-6 4492 carb with auto trans ... does anyone out there have that info?

Thanks

TAZ

[RPOLS3]

I dug out some old information I had and found the following notes from several years ago:

The '70 Chevy Chassis Service Manual lists the L78 and LS-6 Holley as #70 primary and #76 secondary jets.

You may want to double check as I am not certain this is 100% correct. Eric can probably verify.

[RPOLS3]

Here is the old thread I had written it down from:

http://www.chevelles.com/forums/archive/index.php/t-74035.html

[earntaz]

Thanks Jake -- hopefully Eric will chime in ... I don't really want to PM him as most of the time he is busier then a one-armed paper hanger.

TAZ

[VintageMusclecar]

70/76 with 8.5 power valves on both ends.

Bump the primary jets up to 72.

[earntaz]

THANKS ERIC!!!

[JRSully]

Eric, is there noticeable improvement (throttle response.?) bumping the primary jets up to a 72 on a 4492/4557.?

[VintageMusclecar]

Helps driveability/power a little with the crap gas we have to run these days. Throttle response shouldn't be affected, that's more dependent on the idle/transition circuit calibration and accelerator pump settings (taking ignition timing completely out of the equation just for the sake of conversation).

There isn't really "one thing" that you can do to these old carbs to make noticeable differences, it's more so a culmination of addressing several smaller issues which adds up to a larger improvement (hope that made sense?). These old carbs were pretty damned good out of the box, they just need a few minor tweaks and to be brought back to "as new" condition mechanically.

[JRSully]

Thx Eric, I must say the 4557 you rebuilt for me 5-6 years ago still snaps when asked to, very responsive