There's a post running under the Jet Performance board on the same topic...it seems that they make great anchors.
I'v got a pair of 1988 Merc. 454's in my '88 Pachanga that were rebuilt 140 hrs. ago. The heads are the small oval Chevy truck heads ("peanut" Heads). Does anyone have an opinion as to weather having them ported would be worth the effort? Can larger valves be isntalled on these heads?
There's a post running under the Jet Performance board on the same topic...it seems that they make great anchors.
try to find some rectangular heads from the wreckers and rebuild them.Don't bother with those truck heads.
hello I own a small cyl head shop in ohio .
I have superflow 600 flow bench and i do a lot of grinding on heads . I try not to do any work those heads. just not worth the time or money. there great for a stock boat.
hope this helps
The peanuts heads are not from Merc.. Don't spend a buck on them. They are not worth a lot in performance, they are made for economy and low low torque. Their top end is useless.
I think you would get the best performance with the standard oval port heads '70's era or World products. give the (peanut heads)a toss.
You want to use a large oval port head. Around a 269 cc intake runner. Nothing more would be required on a 454. Unless ofcourse you started huffin'.
These heads would be a "high velocity" head. They create a better vac. and swirl the mix in the cylinder creating a more efficient burn.
I had a set on my 502. Worked real nice.
DAVE
Rect. port heads. Port and polish. High comp=POWER!
In my opinion, on a 454, there's only 2 reasons for the need of rectangle port heads:
1.Blower
and/or
2.7000+ rpm
again, my .02
DAVE
Rectangular Port heads come stock on 454HO and 502 HO crate motors- they rock for good reliable performance. The large oval port heads are for racing and super radical high hp aplications.
I had Peanuts and tossed them for rectangulars. Love the new heads.