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700R4 To 4L60E Transmission Swap On A 1989 Pontiac Trans Am - Electronic Overload

EFI Connection, EFI Alchemy, And Century Transmissions Pitch In To Bring An '89 GTA Into The Modern Era With A New 4L60E And 24x PCM System

Justin Cesler Mar 1, 2010

Okay, yes we were promised flying cars by now. And just one month in to 2010, the arrival of these computer-controlled flying awesome-mobiles looks grim. But, that doesn't necessarily mean we have to live in the Stone Age. In fact, thanks to GM and the aftermarket, we are able to reasonably upgrade our older cars with some pretty trick technology, some of which really does make our lives easier. Thanks to the LS1 (love it or hate it), many older-generation F-bodies can now enjoy a much smoother idle, much better driveability and even better gas mileage. But, that's not all that the future can do for us. Hardcore racers can benefit in a ton of ways from this new technology, including higher rpm capabilities, an upgraded coil-near-plug ignition for cleaner spark, and even the use of custom operating systems, which allow for 2 and 3 bar speed density-based tuning or built-in nitrous control.

gmhtp_01_o 700r4_to_4l60e_transmission_swap_on_a_1989_pontiac_trans_am Performance_tuning 2/26

If you have been following along with us, you will remember Byron Jay's '89 GTA, which recently received an EFI Connection LS1 PCM/Ignition upgrade (Feb. '10, "Bridging the Gap"). During our initial install, our goals were simply a smoother-driving 383 with a more calm idle, better street manners, and (of course) a couple of extra horsepower. Unfortunately, after getting everything installed we ran into transmission issues with the old 700-R4 and weren't able to really stretch the LS1 PCM's legs. Enter Century Transmissions and its upgraded 4L60E. A leader in high-performance transmission rebuilds, Century convinced us to ditch the old 700-R4 and upgrade to a much nicer 4L60E unit (identical to the Stage III build we covered in May '09). While this would have been an issue in the past, the EFI Connection harness made it a simple plug-and-play swap, and Century sent us a 27-spline input shaft, which would work perfectly with Byron's existing Yank converter. Transmission en route, we hooked up with EFI Alchemy in Jacksonville, who are well versed in both LSx tuning and this particular wiring harness. Harrison "Doc" Wall, owner of EFI Alchemy, not only ensured us a quality install but also promised to pick up some power, show us some cool custom-OS tricks, and dial in the transmission shift points perfectly. And he didn't disappoint. Follow along as his crew gets us back up and running and he takes it home on the dyno, turning Byron's GTA from an old-school hustler to a new-school machine, capable of impressing even the most futuristic of GMHTP readers.


Century Transmission
Richmond, TX 77469
EFI Alchemy
Green Cove Springs, FL 32043
EFI Connection



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