I have searched the internet and can not find my answer. I found a pair of new ‘Base 502 415HP’ engines at a reasonable price. (Actually everyone that sells them are pretty close in price)

I am trying to decide to build a pair of 496’s or buy crate. I am leaning to building, because I can put forged everything in and some nice heads for the same price.

I can tell you from experience all 502 mercruisers come from the factory with forged crank, rods, and pistons, if its from an aftermarket rebuilder who knows what they will use

their all forged! Eagle engines has new 502 415 hp for 5600.00

call victoy marine. He has brand new from merc ones on the shelf with tins for a fair price.

He advertises here on the board.

Yes, they are all forged internals.

Looks like I will have to do some more research then

Why does it only make 415hp

That is the way the mpi is set up from the factory. The original carbed 503 was only 385 I think.

The exhaust on a factory 502mpi is very restrictive. That is all the power you are going to get out of it.

If you upgrade to a nice header, then there is no reason you can't do a cam swap, and a few other things and get around 550-600HP out of those engines.

A compresion increase wouldn't hurt those things either.

If you want a recipie for a nice 525hp 496, I just built 2 of them and they dynoed very well.

Just a reminder Merc rates them at 415HP @prop shaft. Motor itself puts out more than that.

How about those 496 recipe's!! Weighing options of building 496's or 468's from 454 mags.

My 502,415 HORSE block was junk i am going with a dart 540 and header and new cam shaft but i am told i am limited on horse power because of 502 MPI.

How much HP do you want? The 502 Mag MPI can make 550 easy HP.
I have a friend who did a 502 in a 272 & it runs really well. Close to 70 if not 70 I think.