61 mph? around 5000 rpm wot? do the exhaust like Big Jim said, and 23 prop and you will be around 67-8 with paid for 454. you need those 2 pieces first anyway before anything else will do what it is supposed to. what heads are they? peanut, or oval?

i picked up 2-3mph with dana's on my 7.4mpi in my hammer, that included spinning a 25 mirage plus after install, sell it and go with the 502, you will see real results

300 hp 454? that is a really conservative motor. they are rating small blocks at 300 these days. he might be hitting the rev limiter.

yeah it is at the bottom for sure but run great as long as you can leave it alone, 4400-4800 is the wot rpm range

No it's 4200-4600.

Butteboy has posted about the speed and prop in another thead. He tops out @ 4800 with a 20" 4 blade. That is 9% slip, just below the limiter. It could be a bit more 62ish with an M+ 21" @ 4600-4700 but with that setup 61 for the 300 hp @ 4800 is right on the money. An exhaust upgrade can give you a little as you said, but I'd suspect it to be from the weight saving.

67-68 with the 454 300? Never in a million years.

I agree with your engine guy. Put the blower on and have a ball with it. 30* all in timing and no more than 12af at wot. Nice thing to have would be inconnel exhaust valves and cometic head gaskets if you are going in to the engine. Another nice thing would be to switch your upper gears to 1.5s. You will really like the pop from that little blower and will see an easy 10mph with 5psi. No need to touch exhaust, heads or cam the blower will crutch it all up.

with the exception of thr forged rods[3/8 rodbolt]the internals are cast,but you can supercharge,just keep the boost at 3 lbs,many have done this with great success.

i have to respectfully dissagree, i stand corrected on the wot rpm, but i would see consistent 67-68 out of my 7.4 in my hammer, it was the 310 mpi version, not that it makes a diff, spinning a mirage plus 25 w/ dana exhaust and k&n filter, thats it, it was going through a 1.50 bravo, and yes it was gps speed w my garmin etrex

thanks for the support on the blower blue thunder and AO i agree somewhat with you on the overbuilt thing. i mean its not really a possible thing more so just wasted money up front and thats what he said " marine stuff costs so much because its got a warrentee not ment for people who know how to lift or tune or anything just pin them and get upset when it breaks" so i understand where he's coming from and we go back a bit he's helped with my 500 hp na 650 on button so i mean tunning i can do but not so much this boat stuff my safe idea is keep timing low and throw extra fuel at it

the ringer is my dad is the one who suggested second motor build so when i find another boat in 3-5 years at soonest gotta get life/ gf wife thing all square first

blown hammer your hull is realistically faster esp power for power thanks for the support

and i actually traded a blown up 4.6 ford for some 049 heads with new inconel ex valves TODAY

i agree,100 hp will not gain 10 mph,maybe 6,most likley 5.