SB

iTrader: (1)

This one ? http://documents.holley.com/techlibr...al_listing.pdf

dereknkathy

Ya Mon!! Thanks.

Redneckcustoms13

OK guys I know the stock hp500 carb had staggered jets and they were star pri 75 star sec 93 port pri 81 port sec 89.

With this engine and the environment I live in in mobile AL, what would be your suggestions to start with?

GLENAMY 242SS

iTrader: (1)

Dual AFR Gauge setup

Mr Maine

Stock 420 was 76/87. This same jetting worked well on a 500 horse 30 over 454, low to mid 12s. I would start there or maybe 78/88 to start

Redneckcustoms13

Gary, I have 2 afr set ups I just need to finish making my spacers to install them.

Jeremy, your very close to what a friend locally suggested. He says try 80 88.

I talked to Dan VanderLey at vdl fuel systems today (local race carb builder for automotI've applications) he said he was sorry but hes never been into the marine side of it however he did say that if my carb has 14 separation to keep it that way as I up the secondary up the primary the same amount to keep 14 steps between. Above I'm seeing where your experience was with 11 then 10. Can you help my feeble mind understand this?

Mr Maine

I believe its because a powervalve makes up for about 10 jet sizes. I would go by the afr numbers throughout the range.

Baja Rooster

iTrader: (1)

I believe that I ended up with 78/84 on my 502/850qf with the 4.5 high flow power valves giving me upper 11s across the board with about 12.2 at wot.


Edit in: I plan to lower the primaries down until I get 12s across the board. Going from the stock PVs to the high flow units completely changed the behavior of the carb and I had to start all over again.

Mr Maine

My 850qfs came with 82/94 and 6.5pv. The numbers in the boat were low 12s, i think some high 11s wide open so i dropped to 92 on secondaries. With them on the dyno they were a little lean with that setup. 525 horse 454s

Trash

Same with EFI TBs. You can see it in the MAP readings.