Team Camaro Tech banner

1 - 3 of 3 Posts

·
Premium Member
Joined
·
516 Posts
Discussion Starter #1
Anybody know where you can get a tranny mount for a LS3 with a 700R4. Will the standard flexplate for a automatic on a GMPP LS3 525 HP engine work with a 700R4?
Thanks
 

·
Moderator
Joined
·
14,482 Posts
Call Bowtie Overdrives for a crossmember. The flex plate should work ok.
 

·
Premium Member
Joined
·
13,705 Posts
The LS series engines use a different Flexplate ring-gear offset than the earlier SBC's - so you either need to use a GM LS to TH700 plate that was used in the truck applications (GM #12621399 - comes with pilot spacer) or a aftermarket plate from someone like TCI or others.
The convertor pilot is also smaller on the TH-series than newer trans convertors - so you need a spacer to support and position (keep pushed rearward) it correctly.
The bolt hole Circle is also different on the TH-series convertors vs. the later /4/6L'-series transmissions - the TH-series being slightly smaller in dia.
You can file/dremel the LS plate holes to match the TH-series convertors quite easy, just takes a little time ...

Another thing that may throw you - is that the older transmissions use fewer mount bolts to the engine belhousing than the newer units. It's not a big deal for most applications, just install the 5(or so) bolts that do line up and go with it. If the non-used holes really bother you feel free to layout and drill the trans flange for more, I've never had a problem going with what's there yet ...

There are lots of sites, like LS1tech.com that have additional information on these swaps that you might want to search through for issues and information on your project.
 
1 - 3 of 3 Posts
Top