[Hib Halverson]

I envy you owning one of those cars. In 1989, the Turbo TransAm was the quickest (and may have, also, been the fastest) car GM sold. They also handled pretty well because of less weight on the front end.

Again, the heads you're talking about are not "Pontiac Heads".

They were based on the Buick 3.8L design. Buick was responsible for the 3.8 and its offspring, the 3800 Series 1, not Pontiac...though the Pontiac folks brokered an excellent deal to use that engine in the Anniversary TTA.

When GM Powertrain was created in 1991, it took what Buick had done cylinder head wise and developed the 3800 Series II and, later, the 3800 Series III, both of which used that revised head design.

The head may required different headers because the exhaust port flange was changed.

That head was eventually used on 3800 S1, II and III engines in Chevrolets, Pontiacs, Oldsmobiles, Buicks and Holdens. The final supercharged version (L32) used a "revised-revised" version of the head.

Production of 3800s ended in August of 2008. It was one of GM's better engines and was on Ward's 10 Best Engines list.

I have the same head, somewhat modified, on the 3800SII (L36) in my '01 Camaro. It's a pretty darn good head for an engine like that but...too bad they never did one in aluminum.