LS Flexplates for TH350, TH400, or 700R4
In this video, Pat from the Tech Team talks to you about LS flex plates for everyone out there doing LS swaps to old-school turbo 350, 400, or 700r4 transmissions.
Not everybody wants to use the 4L60E or 4L80e that came behind the motors because if you're like me you're a little cheap and you just want to use the transmission that's already in the car. Let's say you just went out and bought your junkyard LS for an 8, 5.3, or 6-liter truck motor and it already has a flex plate. That's awesome, we're halfway there to mate in those two up. However, f you want to run that old-school TH350, TH400, or 700R4 behind an LS motor, you will need a couple of parts to make it work. If you have a junkyard 4.8, 5.3, or 6.0L LS, take a look and see what style of flexplate you have.
Most of the 5.3's came with a concave style flexplate. You can tell because the center of the plate will protrude towards the motor. If you have this plate, all you need is P/N 57518346. This sleeve slides onto the nose of the torque converter and helps align the unit into the flexplate.
Now if you like me you bought a motor the flex plate was way out of balance when you try to run it, it was off, is cracked, or you just want something new, Speedway Motors carries a kit from TCI that has everything for you; P/N 282399753. This kit gets you the 6.0L style flexplate, the sleeve, and the flexplate to crankshaft bolts. This flexplate is built .35” thicker and so you do not need an adapter plate. The adapter is built right in!
Using these combinations of parts from Speedway Motors will hopefully help you make that LS install a lot easier.
Products Featured in this Article
ARP 244-2901 Chevy Gen III/LS Flexplate BoltsView$24.99Compare