GT40 heads at SkiDim

OK here goes, I had a chance to take out the boat today but only for about a ½ hour, I hooked up the o’l toilet plunger fake a lake in the driveway and got it tuned first. I put on gt40p heads, Weiand stealth dual plane intake, carb and a Mallory Unilite, all at once. , I know I know, don’t swap more than one thing at a time, ,but at the time how could I wait.
I’m pleased with the performance, seems to spin more freely, I know it breathes better, remember it’s an air pump but it’s hard to tell, it’s not rubber on the road, it’s a prop spinning and slipping in the water. I know it sounds like you’re going to town with the engine cover off on the lake.
It had a slight stutter gunning it after idling for a while but no oil leaks or water. Just knowing what I have under the hood is half the fun.

The old heads where D8OE 69cc chambers I think. Might try the original Holley too.

I'm doing the gt40P Explorer head swap now. The head exhaust port is a good match for the SkiDim sold exhaust gasket and a better fit to the manifold, in other words the exhaust manifold is a little bit bigger than the gt40p head port. I've got to tell you these stock ford gt40p heads look much better than the 351 heads that came on the motor, speaking of the smooth and larger ports and they have a raised valve cover gasket seat for better sealing if anybody's had that problem. The last thing I had to tweak was a 64 El Camino but sold it, that was the first motor I put after market heads on, it made a big difference from stock. You can cam it, replace the intake but if you leave the stock small heads on you still have a bottle neck path.

Thats a great site. If you read many of the posts on those sites, They seem to swap heads all the time, with little concern for the change in combustion chamber volume, but more concern for the flow.

Dallas

So is anyone using a set of heads other than what was stock on there 351 engine? Any issues with useing Aluminum vs cast iron?
Thanks
Dallas

77stang,

I've got the old heads/valves on mine and am sure one day the unleaded will ruin my performance so a "head" upgrade is in the near future. Hollman and Moody installed a lot of 351 heads that have larger valves than a 289 head. The original 289 heads can have larger valves put in for about$300 total and this could be a better "flow match" for your exhaust. I've got BARR Marine and am not sure how they work (or restrict) the performance of a high dollar head like GT40's or Edelbrock.

I love my old boat, but quite frankly for a 16' Tow boat that does strange things at 40-50 MPH I don't really need more HP. A reduction in prop pitch is all my "water tractor" needs. With the 12RH14 Prop it still pulls a 250Lb Slalom skier on a very small ski.

Heads alone are a good upgrade as long as your exhaust header is not the choke point...that's what I'd like workky to tell us.

It is very cool though to be able to "snatch" the 250 LB slalom out of the water after your friends big Sea Ray drags him for 20 yards....but the Sea Ray was full of beer and thongs.......

workky,

How did the new heads turn out. What exhaust were you using and did you feel any gain?

I'm running Barr marine and am worried they'll hide any positive affects a quality head may have???

Ford Racing Mag 2004

GT-40 "Turbo-Swirl" Aluminum heads @ $525/per complete w/ 1.94-1.54

GT-40X $625/per with an option of 58cc or 64cc with the same valves as above.

Skidim is a great place, and I love Summit Racing also, but sometime Ford Racing is hard to beat and they do have a good technical staff.

or call and ask vince

Anyone see this? So the GT40 heads are floating back around.... I have the 92' PCM ford 351.... is it worth the upgrade for the heads to purchase them at $695 each....

if I do purchase them... how hard is it to bolt new heads on?