Heads, whick one cools the center ex the best ?
 

Is there a consensus with the aftermarket PMD style heads as to which ones have the best cooling around the center exhaust ?
Is there much of a difference ? Tiger, High Port E head ect.

The E head pro port with its coolant feed hole in the center of the head.

A thermal coating applied inside the center ports on any head (especially Aliuminum) helps a good amount with burning head gaskets and extremes of thermal expansion that takes place there to chew up the head gasket over time.

So how much did the coated exhaust ports extend the life of head gaskets in your testing?

Available heads. Is there a difference ?

Can't say slowbird as the head gaskets have yet to fail, but test with a thermal gun show 45 degree drop in temp at the junction of the spark plug hole roll over point and the head surface just above the deck of the block.

In regards to common available aftermarket heads I can't say , but I would tend to think that a factory iron Block with its far greater gap in between each Bore and hence coolant flow would cool the center of the motor down each bank better then a aftermarket Siamese Bore block , or a near Siamese Bore block .
Just guessing here!

You can apply the same added center hose deal as the E pro port heads even to factory iron heads no less aftermarket heads.

The iron heads have plenty of wall thickness to drill and tap a 1/2" pipe hole in the side wall of the heads.

Ram air 5 layout

There are a couple of pro ports out and about. :-)

I have dealt with old '61-'63 sd heads over the years and on one set of 980s someone had drilled a hole in the water jacket of the dual center exhaust on both sides and tapped them. I have no way of knowing if they had been NASCAR heads or drag race but the only reason they would have done this IMO would have been to install a heater hose pipe in that location on both sides to get the heat out more rapidly. Additionally I've had several sd dual quad intakes with additional threaded holes on the rear flanges both sides which too would have been to screw heater hose pipes in so heat could be more readily removed from the back of the engines/heads. These same tricks could be done on any Pontiac head. How efficient this was I haven't a clue.

With a Billet head it doesn’t matter about any coolant mods.

Head gasket issues are a thing of the past.

With a Billet head can you make back to back passes or how does it work?


George

x2.

Chief Big B X3

DCI RAM AIR V

But can the ra5 heads match or exceed the power potential of the other heads?

Before or after the head gaskets blow between the center ports? 😝

HAHAHAHAHHAH

We all know the RAV does away with that extra heat. High Port, Tiger or E head. Are they all the same or is one better.
I thought that High Ports had better cooling there. Do they ?

I STILL don't believe a head with a pushrod in the port will out perform NA head without.SHOW me!And I breath and bleed RA V!Tom

You know whats really funny.........you don't have to believe!


GTO George