Thanks in advance.
Does a 7.4 mpi stock exhaust +header fit a 502 cid carb long block engine with 450hp?
If it does, does it drop performance?

It will fit and you wont notice any difference with no more HP than you are asking about. Get some 496 exhaust manifolds and use them...they will be better. All you have to do is make the mounting holes alittle larger in diameter.

Wonderful thanks.
Btw, How good are these 502/450hp marine long block that's available? Can they easily be upgraded to 500hp with some bolt-on mods? I'm making mine carb.
Thanks

I dont know anything about whatever long blocks that you are talking about. I went long block one time with what I thought would be a good motor and it ended up being a POS. Since then, I dont buy anything rebuilt because you dont know what parts are in the motor...cast or forged. I have also found out that it really doesnt matter what they tell you about the motor...it usually isnt true.

did they by any chance give you a build sheet with the engiine?
if you can, find out what is in it. It should have forged pistions and steel crank. 450hp for a 502 is mild, the question is how did they get there hp rating, you can bolt on some hp with a good exaust sys. and carb & intake, but it would be good if you knew what cam it had.
larry

I have some stock 496 manifolds that I took of my 02 Nordic Heat that I would sell for cheap. I put lighting headers on this winter. Call me well work out a deal

Thanks Brayden 509 220 1378

Ive got a set of fresh, powdercoated GILs w tubes for cheap.

Email if interested...
[email protected]

Kevin