Good amount of experience with this stuff, just not a lot with boats. Holley 750 vacuum secondary on a 455 Olds in a jet boat.  Where would you start for a jet and power valve?  I'll get the vacuum gauge out and do it right after a bit.  Just looking for a starting point.

Thanks!  I'll check that out.  Took old 750 Edelbrock off last night and found the spread bore/square bore adapter upside down ‍♂️.  For now I put in a Holley 750 vac sec, with 72 primary jets, a 4.5 power valve, and the light (white) spring for the secondary while I rebuild the double pumper I just got.  Gonna check ignition timing and reset it to 12* initial, 34 all in by 2500 and disconnect the vacuum advance, and see where that gets me.  Hope to be testing in the water Sat

Ran it with 72s, white spring, 4.5 pv.  Ran decent WOT at 4K, but plugged 2 more filters and fought me home?  runs good for about 90 seconds - 2 minutes then starts to bog from plugged filters.  Didn?t notice right away, but 30 seconds after it died I watched the fuel filter contents fall off the element to the bottom.  Spent most of the afternoon resealing the thermostat housing (to find it empty) and then switching to a 4160 from a edelbrock?.