Originally Posted by mcollinstn (Post 3916006)

Gil manifolds DO help.
They probably are good for 10hp on a 454 Mag, and maybe 12-14hp on a 502Mag.

That puts your 454 Mags at maybe 375 instead of 365, but it technically doesn't change the ENGINE RATING.

Not sure where you're getting the 40hp difference, though unless you're counting the drop from crank rating to prop rating.

It's really irrelevant if you plan to add hop up goodies. Once you change the cam, do some port cleanup on the heads, bore notch the cylinders, and zero deck the block you're going to be well over 400-430hp. You have a good motor to start with.

Just be glad it's not the 330 version, which has weaker bottom end and poor flowing heads.

Originally Posted by Captain YARRR (Post 3916007)

Probably best to grab some serial numbers so you can know for sure.

Originally Posted by soldier4402 (Post 3916656)

Ok i looked last night at the performance sheet the day the boat was ran, actually had a time, date, and test drive Actually had Reggies signature there, for those making jokes. It did say 365hp for each engine, so the case is now closed. But I find it funny how Nada, insurance keeps saying their 385s.

Originally Posted by soldier4402 (Post 3916656)

Ok i looked last night at the performance sheet the day the boat was ran, actually had a time, date, and test drive Actually had Reggies signature there, for those making jokes. It did say 365hp for each engine, so the case is now closed. But I find it funny how Nada, insurance keeps saying their 385s.

Originally Posted by dandercam1 (Post 3917049)

I doubt the data entry geeks for the NADA database are mercury engine experts. I have noticed other errors on the NADA website and unfortunately this is the information that the insurance companies have to work with

Originally Posted by soldier4402 (Post 3917060)

yeah i doubt their pricing as it is. If i check my 91 it says 17k for the thing, and I dont think you could fine a running fountain for under 20