Just picked up an LT4 swapped '86 C10

[Bextreme04]

I believe they're 3.08s, which are not ideal but I'm running a th350 so probably the best compromise currently. I may looking into an OD trans in the future (potentially 700r4) with some better gearing in the 3.40-70 range, but TBD on that.

Since you already have the EFI and whatever computer running the LT4, you might as well just drop in a 95-newer 4L60e instead of a junk 700R4. They are basically the same trans, but with a bunch of reliability improvements in the 4L60 and no TV cable since it is all electronically controlled by the computer. It also lets you easily adjust the trans shift points and lockup with an OBD2 tool.

 

[F51 LRS]

Since you already have the EFI and whatever computer running the LT4, you might as well just drop in a 95-newer 4L60e instead of a junk 700R4. They are basically the same trans, but with a bunch of reliability improvements in the 4L60 and no TV cable since it is all electronically controlled by the computer. It also lets you easily adjust the trans shift points and lockup with an OBD2 tool.

That's a good shout, too. I haven't put a ton of thought into the trans just yet - I'll probably leave well enough alone until I decide to figure out all the wiring for an e trans.