Smitty, what do you do with the breather tube from the valve cover that attaches directly to the newer style Mercruiser spark arrestor and the billet K&N when you switch to the older Mercruiser flame arrestor that has no provision for this?

Years ago on this motor I got rid of the pcv valve, stock oil filler fitting and made 2 tall breather tubes with clamp on breathers, you NEVER want to introduce hot oil vapor into the intake of any performance motor in my opinion.
Finished dynoing this motor a few weeks ago, currently installing in Baja and un-rigging all the stuff I had in it for blower. Final results AFTER placing intake air probe directly into flame arrestor and correcting for exact intake temp was 565 hp and 589 ft lbs of tq, expecting Baja to run 72/73 light and a honest 70/71 full tank fuel , 4 passengers. Its going to make someone a nice boat!

Smitty, was the 565hp with the stock intake?

No, with my fully modded 502 mpi intake I used to run on my blower motor along with a TPIS twin 68 mm throttle body. this 502 is only 8.7-1 or so (flat tops, not mini domes) though and has 088 iron heads I ported slightly myself. Would have been pretty cool to see what 10-1, a bigger cam and AFR or equivilant heads would have done!

How did the boat end up running Smitty? What RPM did you prop for?

Boat ran 69/70 gps when i sold it w 24 non labbed at 5200 with full tank of gas so its not really near peak hp, 69/70 w 23 mirage plus at 5800, has 72 at least in it if new owner buys a labbed 24, he has told me he saw 71 gps on it with less gas since getting it from me, it ran 62/63 gps with stock 502 mpi when it was fairly new and stock so he's seeing anout 8mph over stock, remember we dynoed this w really good car headers and no accessory s so its prob around 520 hp as installed

If you had just bolted on an 850 Holley and a Dart intake, do you think the final results would be any different?

With the 500 efi cam prob same results!

Updates?

Baldie, can you send me the files you mentioned.
i have a Mefi 3 that i have a tuning program for.

Kurt

I sent you a private message with my contact info.