Is this a v6 Turbo ZR-1 Prototype Engine? Friend purchased it (pics) ---

[alwayscode390]

J-Bonez the engine in the 89 TTA Trans Am was just the Turbo Buick 3.8 lc2 engine but with pontiac heads. Could have been planned for it , but I would expect Pontiac Power Valve covers? ---

[Hib Halverson]

The engine in the Turbo TransAms from 1989, were Buick 3.8 turbos. No "Pontiac heads". The build was so small, Pontiac would have never done a specific head. Not only would the head have cost a fortune but Pontiac would also have had to certify the engine with the EPA. It made much more sense to use the engine right from Buick.

Either way, that was a bad-*ssed car for 1989. I remember road testing a couple of them for magazines back then.

[alwayscode390]

Sorry but you are wrong Hib, I used to own a TTA , #5 to be exact.

They require different headers than the Buicks.

Here is a very informative post , look down a couple posts :

http://www.turbobuick.com/forums/thr...-ports.391515/

They didn't make a "specific head" , they used already commercially available heads off the "3800 traverse v6" engine already in production that actually outperformed stock lc2 Buick heads!

" It was fitted with cylinder heads from the existing traverse V-6 3800 Series I heads, PN: 25536702, which yielded superior combustion chamber design & exhaust flow of the GN/GNX design. It allowed room for the downpipe to fit, and also gave more clearance around the strut towers & A/C box on the firewall. " ---

[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.

[alwayscode390]

When u said they took the engine right from Buick you made it seem that it was a 100% straight engine transplant and it was not. In that link i posted it tells all the differences. Thanks for the technical information ---

[Hib Halverson]

I know this is an old thread, but I'm doing an article for Corvette Magazine about some of the development vehicles which led up to the ZR-1.

The engine in the OP's photos is a 4.3-L V6-90 with splayed-valve heads and a single turbo which was the first engine configuratioan tested for what was known inside GM back in '83 as the "400 horsepower package" an idea which predates the LT5 development by a couple of years.

As Dave McLellan points out in his book, the V6 single-turbo was quickly rejected because: 1) it made not much more power than L98 which was coming for 1985 and 2) the noise and vibration characteristics of a C4 with a 4.3L V6 were awful.

The next step was a V8 twin turbo, of which 14.5* were built. That idea never went to production either because Lloyd Ruess believed it would be rejected as low-tech once it got to market. The technology developed during the factory TT program was given to Reeves Callaway and GM moved on to DOHC heads for the SBV8 and, subsequently, to the LT5.

*I say "14.5" because 14 coupes were built. Then, right at the end of the program, the powertrain from the last coupe was removed and transplanted into a convertible. Of the 14 engines built, 13 were "standard" 440-hp versions, but the last was a 560-hp version with an induction system having larger runners, a bigger plenum and 20-psi boost.

Digging up some of this old stuff is quite educational.