Engine Elusive GT40X Turbo Swirl Aluminum Heads??


New Member
May 19, 2022
I have an '89 LX Convertible 5.0. Some people refer to it as an anniversary edition, however it's not...they just say that because of the "25 years" badge on the dash. It is however a very an uncommon set up (ordered from factory)... It's black with white rag top and white leather interior.

So...don't to business. I'm getting ready to rebuild this car with my youngest son. I'd like to get more HP from bolt-on's only and want to keep it "fairly" stock....not completely. After research, I've decided on GT40X heads, E303 Cam, 70mm throttle body and the other basics like distributor upgrade, new rings, new exhaust etc.

The dilemma! I cannot find GT40X heads anywhere! Have they been replaced? New model number? Does anyone know where I might find a set of these heads?

Thanks to all!!


You have a nice rear end there Dave.
15 Year Member
Nov 29, 1999
Mililani, Hawaii
I have GT40X aluminum heads on one of my cars. I love them. I also had the above mentioned AFR heads on my coupe, before swapping to TFS heads with a turbo. I loved the AFR heads also. I always felt the AFR heads made better power and felt stronger. I would go with the AFR as my first choice, BUT I certainly think the GT40 heads are a good quality head as well.


SN Certified Technician
Aug 8, 2003
Used at a good price, gt40x valve jobbed would be great.
Out of the box they really are mediocre at best. The factory machine work wasn't that great.
Optimally, buy a used set, then spend another $250 on them (maybe $350 if they need springs).
I had a set, i would use them again, but not at $1300 a set new.