[bigtymer83180]

i have chevy 350 with flat top pistons,edelbrock intake,and a mild cam. i was just wondering what size jets should i put in the primary and secondary side of my 600 cfm holley. the holley is mechanical secondaries. thanx

[engineczar]

What number 600 Holley do you have? The number is on the front of the choke horn. There is no magic number as far as jets. 600 Holley's might use anywhere from 63's to 69's on the primaries and 70's to 76's on the secondaries if the secondaries aren't a metering plate. With that number we can determine what that carb came with stock, then we can go from there.

[bigtymer83180]

it is a 6210

[engineczar]

Well that's a different number.........

According to my notes that's actually a 650 with emissions calibrations. Not exactly your run of the mill performance 4bbl. I'm not sure what to say now, the jets are listed as 122-602 on the primaries and 122-632 on the secondaries which equates to ????? in relation to normal Holley jet sizes. Other 650 Holleys use 67's on the primaries and 76's on the secondaries but with the emissions calibration they might be too large. You could start there and adjust as needed by reading the spark plugs but I have a feeling that the final jet sizes might be quite a bit smaller.

[barnym17]

That translates to a 60 primary and 63 secondary, but I would bump it to 64 primary 67 secondary and tune from there.It should be slightly rich with the jets I recomended, but a little rich won't kill an engine a little lean can.Just do normal plug readings to check the jetting and adjust accordingly.