[QUOTE=ghittner;2556956]I have a set of oval port World Casting steel heads on my blown 489. I am Running a B&M 420 w/ 8 Pds boost and dual 750's Here are the head specs.
While I think about it, ditch the 750's and go for some dominators. Blowers really like those. With regard to the advice on smaller intake runners, I'm sure they mean well...
Consider this: as long as your have positive pressure--boost--in the intake manifold, the induction system is restricting the air flow.
Built a 548 with 269 oval Merlins for a good customer of mine, because thats what he had. Didnt want to use them but we did anyway. 234/242 @.050 Crane hyd. roller, 8-71, Chiller, 8.2 comp ratio, Eddie manifolds, 2x750 and a rectangle manifold and just over 6lbs of boost. Almost 810 HP at 5600. Who would have though. Crazy in a open bow Cole 21 with Imco drive swingin' a lab 32.
i'd buy a intercooler, before I swaped out the heads... its the cheapest hp you will ever buy
i'd buy a intercooler, before I swaped out the heads... its the cheapest hp you will ever buy
+1....
I'm running a 420 with a chiller at 10psi, on 91 octane. No problems at all. An intercooler on a boat, just makes too much sense.
Darrell.
on a 454" 6 or 8-71 blown pump gas motor at what point should you absolutely step up to square port heads? 5k rpm 5.5k rpm or 6K rpm? if a guy has the merlin oval ports or even 049-781 castings with 2.19-1.88 valves with bowl work how much of a jump would you see with 990's or any decent aftermarket square port head. i'm just curious thanx mike
i'd buy a intercooler, before I swaped out the heads... its the cheapest hp you will ever buy
No room(
Rat Tuned, if this helps. Almost same combo as above but 516 inches 6-71 800 carbs 830 horse with all else the same but with Edelbrock rectangles at 7.8 to 1.
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