Stroking a 454 Mag 360 hp advice
 

I am wanting to stroke my 1988 Formula 242LS with a 44 Mag to a 496. I have a friend that has a 454 Stroker Crank and push rods I can get for 750.00 and will need to get some pistons. I was wanting to get some input on what else will need to be upgraded to make a consitently good running engine with long life. Right now the engine is stock. I am already planning on a roller cam but have no idea which one to buy. I have another friend that has some Gil Big Gun exhaust manifolds that I am considering buying if my stock ones wont work. He only has the manifolds so I will have to buy some risers. He wants 400 for the manifolds. What I am looking for is some advise of how much of a hassel I am looking at or is their someone that has done this that can give me a basic setup to start from. Camshaft, pistons, carb, jetting, etc. I am sure there are alot of guys that have done this. Would appreciate any help. The engine is already out of the boat and in pieces and I am prepared to spend 2 - 3,000 but would like to spend as little as possible. I wnat to do it right but don't to buy parts that aren't necessary for the life of the motor and will only net me small increases in power. I'm not into poker runs or racing but would like to get the boat in teh low 70's. thanks, Jim

Re: Stroking a 454 Mag 360 hp advice
 

I don't think you are going to accomplish your goals on that budget. First off, you will need to get a good aftermarket exhaust. The stock exhaust from Merc. is junk. You can't modify the motor with that exhaust. You can expect to pay about $2K-$3k for a basic set-up from any exhaust manufacturer. Even if your friends used manifolds are good, you will need a set of risers. They are not cheap.
If you want to put add a 1/4" stroke to the crank, that is a good start. But, along with that you will need to move some air. What heads do you have now? Maybe a port job will pick them up a bit.
Hydraulic roller cams are great. They seem to work well. I just ordered a set-up from Isky for a 540 that I am building. I don't remember exactly, but I think I paid about $900 for the cam, lifters, chain and some additional small parts.
I think that you should spend your money on good exhaust and just freshen up the parts that you have now. Maybe a good port job to the heads and a cam will pick up the speed a bit.

Re: Stroking a 454 Mag 360 hp advice
 

I can't remember the year that the 454Mag went from 330horse to 365 horse, but I believe you have the 365 horse version. If you do NOT have the 365 horse verision then give it up right now and look for a good 502 to replace it with.

You can tell which one you have by the intake manifold. The 330 has a low rise cast iron manifold. The 365 has a medium rise aluminum intake. A magnet will tell the tale.

Formula often uses a 3" exhaust riser on the factory intakes to line them up with the thru hull fittings. Your friend's manifolds will probably need custom tailpipes to match up with the Formula holes. Maybe not. You'd better check.

A decent stroker 454 will run good on a crane 731 or equivalent. This is close to the 500EFI cam, which is almost as good but costs a lot more. You'll need retro lifters, the cam, a timing set, pushrods, rockers, and valvesprings.

You say your friend has the crank and pushrods, but what do you mean by pushrods? Pushrods are matched to a lifter/cam/valvestem length, not a crankshaft... If you mean piston rods, there's nothing wrong with the ones you already have, assuming you have a 365 hp motor...

Yes, you'll need pistons matched to your stroke and rod length.

A blower on your existing motor may be more cost effective...