baja36ft

I WILL SELL YOU A HP500 (EFI)COMPLETE WITH 100 HRS ON A REBUILD FOR 9,000.00 WITH CMI EXHAUST...

cbellamore

a set of nicely ported large oval heads will make well over 600hp with 454 inches and around 10 to 1 compression,
you can even run 10.5 to 1 if you want to run 93 ocatane gas all the time and make a little more power

what heads do you have on your motor that only makes 500 hp ?

Ive done over 700hp with factory cast iron head, that have of course been ported and setup correctly
it can be done
if you already have the heads and can do the assembly work yourself you will usually save a decent amount of money vs. going with aftermarket aluminum heads
but the weight savings with aluminum heads is nice
we all know how heavy those cast iron BBC heads can be

if you want some engine combo advice feel free to email me at [email protected]

jayhawk261

My heads are RHS 320cc heads. I believe the only port work on them is gasket match type work. I have a Tyler Crockett cam that is very similar to the 500 efi cam. My compression is 9.5:1 with the 118cc chambers (roughly). It isn't a monster motor. I believe we'll see some better numbers when we drop the merc efi set up and bolt on the Dart intake and Holley carb. Thinking of swapping the cam as well.

What I was saying was that you're not going to make that HP on stock type heads without major modification. I think I mentioned that. I honestly believe you are better off buying a head that flows better out of the box and can be taken much further than putting a large amount of labor time to port and flow the stock heads. Beyond that you need to cut all of the valve seats to fit larger valves. Even with that, you might not be able to get to the valve size you want due to space restrictions.

In all reality, yes you can make great power on factory GM heads after huge amounts of labor and cash have been spent on them. I personally believe that the better way to go is to move up to an aluminum head and go from there. I would wager the cost between the 2 would be similar in the end. If they are similar in cost and power, which do you choose? Aluminum, or stock?

cbellamore

yeah you should definately go with another cam if your looking for some more power
and maybe even have some head work done on it as well,
it will probably be easier for you to tune with carb setup as well,
so in that case you will probably see some additional power there also

ohh trust me Im not arguing about the aluminum heads at all
I totally agree
but if you have a little bit of experience with engine work and can perform all the labor yourself you will save money especially over buying a merc crate motor
those things are freakin expensive and make very very little power

I have a local guy by me that does great port work at a very reasonable price
Ive been using him for years,
he also sets up great engine combos that make honest reliable power and he really specializes in pump gas setups

I just think that a lot of guys assume they have to pay or spend a lot of money when it comes to boat motors when in fact all the boat motors are very mild compared to drag motors,
A very basic BBC can be built to make well over 600hp on a very tight budget, with mostly stock parts and run very reliable for a very long time

but again Im not disagreeing with the aluminum head setup
they definately will make more power
and if you cant do any of the work yourself then you are going to be close in cost of aftermarket heads,

but if you have the skills and patience and knowledge then you can really save yourself a heap of money and still get great results

endeavour32

iTrader: (4)

I agree with you completely, it frustrates my when people say you have to spend $20,000 for a good motor. The auto mags pride themselves on building strong, low budget engines.

cbellamore

haha yeah I know for around $20K I built my last sbf motor
434 inch dart block setup with 10 degree pro king heads, full jesel valvetrain etc. belt drive billet crank custom pistons best of the best parts
I probably had between $20-$21K into it
with twin 91.5mm turbo's it made over 2000hp

I dont know why a lot of guys think you have to spend $15K to get a decent running BBC that will make 600-700hp
the only thing your really gonna have to shell out for is the exhaust
that stuff is expensive but there are some good used deals out there
I just got a set of stainless marine exhaust manifolds with riser etc. for under $400 off of ebay about 2 weeks ago
deals are out there you just gotta look for them

sorry about the rant and sorry if I steered your thread in the wrong direction
but I belive we emailed each other

I would not bother with that crate motor I would build off of what you already have or check out yellowbullet.com theres a nice 468 BBC that made over 600hp is pretty fresh and I think the guy wanted around $3,500 or so
you would just have to swap the cam out to something more suited for the boat and be on your way

ballon78

ya i did buy a set of merlin heads, what happened was i have been tossing a few things around, looking for parts on craigslist when i found a 454 mag motor, so i went to look at it.....it was old 2 peices rear main seal, and the pan had been left off so the crank was junk im sure. I was going to use that motor as a doner, but it ws wrong gen, the heads on it where half apart...wasnt a good deal, so this was at a boat dealership and the owner said i have a BRAND NEW 496 complete in a create so i started to think if i bout that for 8000.00 retail is 14,000.00 and sold my complete 330 which is mint then a new 496 would only cost me 5000 and it comes with the new nice mercury stainless exhaust, harness, ecm exeryhthing.

I just found out last night it wont work anyways, the heigh on the 496 is way to high and i would have to remove like 4 inch section of my rear seat, even then the serp belts come right to the front hull, no room on the old oulaws, the new 25 ol have tons of room.

so thats where i am at!!!

cbellamore

whats the problem with the height ?
The 496 is just a stroker version of the 454
the outside dimensions should be exactly the same

your boat came stock with a 454 right ?

endeavour32

iTrader: (4)

The 496, I believed is a tall deck. Plus the intake manifold is quite tall and the flame arrester sticks out from the front and tilts up. It is a taller engine overall than a n/a 454.

For $5000 you can still make your engine more powerful, especially if you already have a set of merlin heads.

wfo1

It should fit fine. There is a guy with a 24' outlaw with 496ho with either a whipple or a procharger on it. It was for sale.
I raised my engine 3.5" and have a Merlin single plane with an 1.5" spacer, dominator and a 3" arrestor and still have a bunch of room above it.