The Summit 600 is advertised as a 600 because the large annular boosters create a restriction even though the bore diameter is larger. It's kind of apples to oranges comparison between the Holley and Summit for jet size as the air bleed sizes are quite different and the integrated emulsion tube/booster combo setup changes things a bit as well. I'm at a 66 jet which is up 4 from stock, stock 68 secondary and a 10.5 power valve on my 390 with the 500 CFM summit. I ran my 600 Summit on my 390 when I first got it going and it ran fine at stock jetting although it did need the idle feed restrictors opened up a tad.
I forgot about the bigger booster Apect. I can see how big they are in the bores there huge . The RPM intake has big runners and I noticed it would go leaner in mid range or tip in they call it so I have to put a bigger squirter to accommodate that area . I take the easy route with AFR gauge never been a good plug reader .
The Summit 600 is advertised as a 600 because the large annular boosters create a restriction even though the bore diameter is larger. It's kind of apples to oranges comparison between the Holley and Summit for jet size as the air bleed sizes are quite different and the integrated emulsion tube/booster combo setup changes things a bit as well. I'm at a 66 jet which is up 4 from stock, stock 68 secondary and a 10.5 power valve on my 390 with the 500 CFM summit. I ran my 600 Summit on my 390 when I first got it going and it ran fine at stock jetting although it did need the idle feed restrictors opened up a tad.
I forgot about the bigger booster Apect. I can see how big they are in the bores there huge . The RPM intake has big runners and I noticed it would go leaner in mid range or tip in they call it so I have to put a bigger squirter to accommodate that area . I take the easy route with AFR gauge never been a good plug reader .
@@TheThirdWheel618 I had to put a bigger squirter in both of mine as well.