Bought a boat sight unseen with a "noise" coming from the bottom end on one of them. Seller does not know history on the boat or engines but stated the engines are 454 mags. My builder does not think so from the pics. Figure if anyone can help ID them one of you guru's will know. Also, Ordering prochargers for them begining of the week. Anyone have an opinion on m1 vs m3 prochargers, procharger (the factory) just says "oh ya, get the M3 it's a better unit". Well that doesn't do it for me because while it may be a better unit if it's not going to yield me any benefit for the extra grand a piece why would I want it. I'm not going crazy with mods, I'm rebuilding whatever it is to factory spec, probably refreshing the other engine as well and slapping one of those on @6 psi and seeing where I'm at with performance. (boat is a 283 Checkmate Convincor, black, out of Chicago) Thanks for the help guys.

It may have stared out as a Mag. Which is good. Looks like a Holley carb was added.

If they are 454 mag as represented I'm 100% good with that. My thought is though, why would someone go through all of the trouble to mimic a merc racing product? I have been trying like heck to find info on a hp450 but can't even dig up a pic to compare.

The exhaust is not stock 454 mag right? I see merc stickers on them though.

Stop guessing,because all you can see is what you can see. A BBC with dual plane intake, Holley Carb, and K&N flame arrestors.

The HP450 os exactly like the HP500's but 454's. Same crane hyd roller, dart single plane intake intake, Holley carb,and etc.

Motors is coming apart for the knock right ? So, you'll find out what you have then. Make sure to get the #'s off the cam face too.

Look like Bulldog 540's or possibly the HP500 carb. Any serial numbers?

I agree with sb, get'em out and go from there. Not a whole lot you can tell from the pics. I can tell you they are not bulldogs or anything like that, i dont believe anything over a 420 had dual plane intake. Looks like 365 mags with some goodies bolted on. Gil exhaust and a few other thing, looks like a nice starting point for what you'd like to do.

Motors are coming apart immediately so I can run it for the rest of the season. I know that I will know what they are, but it's a new boat. Just excited. Wasn't sure if any of you guys, who know more than me, would see them and know what they are right away.

With whats pictured your definitely hitting the ground running. Just thinking out loud here but does anyone know what carb motors were still left in 97? Assuming they are factory installs and not counting merc racing blue stuff.

They look like HP465's, they would be the precursor to the HP500 but have milder cams and the blue dual plane intake. You can look at the specs of all these motors as well as find part numbers at http://www.marineengine.com/?gclid=C...FUFk7Aodt2IAIA