Torque converter flexplate TH400 to 700R4

[Subaugusta710]

Hey Guys, I’m deep into TH400 to 700R4 swap and the new 1200 stall TQ is a 3 lug while the old is 6 lug. Different bolt circle diameters. Anyone know what part number for GM 139 tooth flexplate, 14-1/8” OD with 3 bolt 10.75” bolt circle diameter? 1986 M998 with stock 6.2L. Thanks

 

[Mogman]

There are two available one part number Z135 and one Z136, IIRC the Z135 has a smaller bolt hole circle, but more research would be needed.,

ATP Flexplate Steel 139-Tooth External Engine Balance 6.2L Diesel 6.5L Z135 740993023111 | eBay

Find many great new & used options and get the best deals for ATP Flexplate Steel 139-Tooth External Engine Balance 6.2L Diesel 6.5L Z135 at the best online prices at eBay! Free shipping for many products!

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Nether fit the torque converter for my 6L80, I had to customize it.
ATP lists the Z135 as 11.75" and the Z136 at 11.5" but the pictures show the Z135 as having a smaller bolt circle
In all my research when doing the 6L I only found two different flex plates
Z135
Z136

 

[Subaugusta710]

There are two available one part number Z135 and one Z136, IIRC the Z135 has a smaller bolt hole circle, but more research would be needed.,

ATP Flexplate Steel 139-Tooth External Engine Balance 6.2L Diesel 6.5L Z135 740993023111 | eBay

Find many great new & used options and get the best deals for ATP Flexplate Steel 139-Tooth External Engine Balance 6.2L Diesel 6.5L Z135 at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Nether fit the torque converter for my 6L80, I had to customize it.
ATP lists the Z135 as 11.75" and the Z136 at 11.5" but the pictures show the Z135 as having a smaller bolt circle
In all my research when doing the 6L I only found two different flex plates
View attachment 880324Z135
View attachment 880325Z136

Thanks. BCD is 10.75” - If I can’t find one I’ll just drill it.

 

[Mogman]

Others have done this conversion someone will speak up I'm sure.

 

[Subaugusta710]

Others have done this conversion someone will speak up I'm sure.

Drilled the flexplate and torqued up the TQ. Getting ready to mate the 700r4.