Those are for sure oval port heads, You might want to check you engine ID numbers, if memory serves me the 454 Mags used the rectangular port heads, the low perf 454 / 330hp motors used the oval port heads. I had a pair of 1996 454 365hp Mags and they were rectangular port heads. The mags also had the forged crank, rods and pistons, where the 454 330hp engines had cast iorn crank and rods and cast pistons along with the smaller heads. There are also two oval port heads from Chevrolet, the "oval port" style and the smaller "peanut port" style. I believe Merc only used the "oval port" style.

Peanut port heads willl fllow around 250 CFM @ .550 lift fully ported the big ovals start around 240/ 250 and can be ported to flow around 300 @ .550 lift. The ported big ovals will actually pull mmore power than the Edelbrocks. The 2.25 valves on a 454 are shrouded by the bore the 2.19s are better also the Edelbrocks need bowl work to meet there advertized flow numbers.

Fast Enough, I was looking to get $600 for the pair. I had new springs and valves: 2.19"/1.88" put in them[/email] last summer by a very reputable local head guy. He also said that the port blending looked good and wasn't butchered like allot that he has seen.

if interested my e-mail is
jay2one @ hotmail . com

In 87 Merc put Magnum labels on 454-330hp engines. Unfortuately, they are the low performance engines with cast parts. They also put some of these engines in front of Alpha outdrives. A freind of mine has one in a 24 Oulaw.

Alum or Steel?
 

Are they Alum or Steel?

steel