Pontiac Trans Am Engines

11/20/2018
Greg Zyla
 
Q: Hi Greg, I'm a regular reader. I remember an article you wrote a few years back about the flaw in the '93-'94 Pontiac Firebirds and Z28's V8 engine. Does the conversion kit available do anything to the horsepower or top speed to these cars? I'm thinking of buying one. Should I just buy a '95-'97 Pontiac Firebird? From what you know about these cars, is the top speed the same? I’ve been doing research on these cars and I saw different figures. Also, what do you recommend, a Pontiac V8 or Z28 V8? Thanks, email from Ed

A: Ed, first and foremost the top speed of an LT1 350-inch V8 Pontiac Trans-Am or Formula and a Chevy Z28 from the years 1993-1997 are basically the same as long as they came with the Z-rated performance tires. The 1993 and 1994 Trans Am, not to be confused with a Trans Am GT those years, came with 115 mph rated tires and is governed at that top speed. If you buy a 1993 or 1994 Trans-Am Coupe, you can buy a performance computer Hypertech kit which will override the 115-mph top speed and allow the car to run close to 150 with proper gearing and Z-rated tires.
 
Pontiac Drag Racing 
 
The Achilles heel with all 1993-94 Trans-Am and Z28, one of which I own, is that the engine comes with a non-vented optispark ignition. I have replaced mine already twice because if it gets any moisture in there…bye-bye! Also, if you put serious power to the stock rear end, expect to replace it as it will not hold up.
 
In 1995 and up, GM upgraded the Optispark ignition on the LT1 V8 engines as they come with a vented Optispark, which work well. The conversion kits you mention will help, but will not increase the top speed. Also, some 1993-1994 Optisparks have lasted over 100,000 miles, mine lasted about 8,000.
 
If you purchase a 1998 to 2002 Trans-Am or Z28, both come with the LS1 engine, which is completely different that the LT1, especially the ignition system and are mechanically superior to the LT1 in the 1993 to 1997 Pontiacs and Camaros.As for my personal choice, I own a '94 Trans Am LT1 and a '98 Z28, that we put an LS6 Corvette crate engine into with a 4L65E GM automatic transmission. My son and I also replaced the rear on the Z28 to a Moser M9 9-inch with 3.89 gears.
 
Overall, the LS1 may be a better way to go, but there is nothing wrong with a clean, pre-1998 LT1 powered Trans Am or Z28 either. Good luck, and let me know which way you go. Remember, too, that the Pontiac V8 and Z28 V8 are identical, be it an LT1 or an LS1.
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