Th400 swappers use this!

[DCx]

Look up this part number in any search engine:

Apt z270 flexplate

Its a brand new 6.0 flat flexplate, crank spacer, and bolts for around $50-$65. Much cheaper than using the over priced gm spacer and bolts with a curved ls1 or 5.3 flexplate! It allows for the use of a 11.5" th400 converter, not the small th350 10.75 converter bolt circle.

[Toddoky]

Look up this part number in any search engine:

Apt z270 flexplate

Its a brand new 6.0 flat flexplate, crank spacer, and bolts for around $50-$65. Much cheaper than using the over priced gm spacer and bolts with a curved ls1 or 5.3 flexplate! It allows for the use of a 11.5" th400 converter, not the small th350 10.75 converter bolt circle.

Good info indeed. If you need a crossmember for mounting a TH400 behind an LS engine, the new Hooker T56 crossmember has been validated to work well for that purpose by merely installing a 1-1/4" tall spacer block between the crossmember and the trans mount. Here's a photo of the install...

[DCx]