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Going to be installing the 400 that I've finally finished building next Saturday. Question is, is it necessary to remove the pilot bearing from the crank...or is it OK to just let it be? Another thing that I noticed that the sticky didn't cover was if the stock driveshaft length would work with the 400 and 10bolt. Amy help would be appreciated.
I think you will find your stock driveshaft is 2" to 2.5" too short for the 400.
If you need to remove the pilot bearing will vary on how you did the swap.
If using a crank spacer,
the GM truck one.. might not need to remove bearing.
The Hughes style crank spacer .. you do need remove the pilot bearing.
If you have a purpose built ls1-TH400 converter.. again need to remove pilot bearing.
Plus it weighs a gram or two, so remove it anyway LOL
Thanks. Welp, looks like I need to get under there and pull it. I'm using a PTC converter specific to LS. Know of anyone that makes some type of Mount that works with the stick torque arm.....that isn't almost $300? I've found some mounts, but they cost more than I care to spend. Of course, if I have to then I will.
I went through the same thing with my mount. I haven't seen a cheaper option. I thought about fabbing something, but at the end of the day I couldn't go past the easiness of just buying the BMR mount and poly bushing. Plus you get a lot of adjustment holes with it. The stock length torque arms with relocation mount poly front bushing and adjustability can 60ft very well. One guy one here with an 8.9 second nitrous stock bottom end ls1 has only that. 60's 1.2 something
Here's my TH400 BMR relocation mount. Bolted straight up and perfect when i first test fitted it for doing the LS swap.
But I then decided to move my engine back 1" from stock and also center my engine/transmission in the chassis. So I then had to modify the mount a little for the transmission mount, which is why the bolts for the trans mount are now offset to the left hand side and sticking out the back of it on extra plate I welded on....
I also have a Pontiac long extension housing on my TH400 which is 5.5" longer than the short TH400's
Here's my TH400 BMR relocation mount. Bolted straight up and perfect when i first test fitted it for doing the LS swap.
But I then decided to move my engine back 1" from stock and also center my engine/transmission in the chassis. So I then had to modify the mount a little for the transmission mount, which is why the bolts for the trans mount are now offset to the left hand side and sticking out the back of it on extra plate I welded on....
I also have a Pontiac long extension housing on my TH400 which is 5.5" longer than the short TH400's
So even with the long tail, your driveshaft was still short? And did the kit you ordered come with the clam shell? I ask because I forgot to keep mine when I sold the t56. Not that serious of a deal, but was just curious. And thanks for the pic.
So even with the long tail, your driveshaft was still short? And did the kit you ordered come with the clam shell? I ask because I forgot to keep mine when I sold the t56. Not that serious of a deal, but was just curious. And thanks for the pic.
Nah, the other way around, the long tail I have made the driveshaft need to be shorter than the stock 4l60 driveshaft.
If your TH400 has the typical short tail, you will be the other way around, you will need a 2 to 2.5 " longer driveshaft over your stock 4l60 one.
The relocation mount didn't come with a poly bushing from memory. I think I bought the UMI brand one at the time because Summit had it in stock.
you can still use the t56 crossmember for a short tail. that helps with the support. works out perfectly BUT you still need a longer driveshaft. don't forget the yoke don't recall the differences on these
02-01-2017, 09:35 PM
M6 to Th400 swap (already checked sticky) 
