509". 268741 cam

I converted a 454 mag efi with eq320's a couple weeks ago to a dual plane with a small Holley. Customer took the boat out and called while still on the water and said "holy sh!t this thing flies".

On a 532 with Eq 320's at 9.5:1 motor made 650hp @5700 small cam. I bet these heads would go 700 with the right cam on a 540" motor. Spend some money on port work, tunnel ram 2-4's and who knows 750-800???

The 532 made 650/650...

HE should really like the 130hp increase.

Yup, like 60-70hp increase going to carb. Been a few builds up's exactly same (including same heads(RHS,now EQ, identical cam, same 502-509cid and compression) with carburetors. 600-620hp.

EFI too using the Holley EFI intake
http://www.carid.com/images/holley/i...s/9901-203.jpg

Thanks SB. He's happy so I'm happy. It's going to be a completely different boat.

Good info guys.

Black Baja, Im surprised the 454 made any power with a 320cc cylinder head. I was told a 320cc head on a 454 would equal a gutless turd :cool-smiley-011:

Seriosuly though, its nice to see theres another iron head option for us performance boaters out there.

What are you guys paying for the bare castings? PM me if you want.

425 per casting shipped to my door

MT - is your exhaust on yet ?

If not, and I mentioned this before, would be cool (and good) to see how the exhaust ports compare to the exhaust.

I kind of wish more people (including myself at times) would check to see if the exhaust manifold port openings don't protrude over the cyl head port openings. The times I had done this on automobiles, usually proved worthwhile,

Only takes about 15 minutes or so.

I've usually described how to do it, but looking for an article I can link instead, just found this on Stahl's site that explains it.
http://www.stahlheaders.com/ports.htm then scroll to 2nd half of page.

Thats good info.

Ran mine on the dyno yesterday.

468ci
8:1 static
EQ heads
236/245 114 LSA .630/.630 lift cam
Stellings green headers with 1 7/8 primarys and 4" tails
B&M 420 blower with chiller

Ran in full marine trim, made 818HP with 8psi boost.

My last combo, was same shortblock, dart heads, 9:1 static, no chiller, same cams, made 800HP with no accessories, 2.25ID open dyno headers, 7lbs boost. Hard to compare, as major changes made, plus totally different dyno.

I will say, I had to add a chit ton more jetting to get the AFR's to where they were with old combo. Guess the boat will tell the story as far as if I am making more power in the boat.

Ran and made final tuning adjustments with the boat I built the MPI's for yesterday. So far I've seen a 500rpm gain.

No idea what speed but the old setup was spinning 5000. New setup is 5500 with full load of fuel and two guys.

I'm gonna guess mid 70's mph. I was too busy with watching AFR's while monitoring MAP readings and making tuning adjustments to the fuel table to see how fast we were going. But anyway, the 500 rpm gain tells the story of the power the package I built has over stock.