Fixing some leaks

[Mryan]

I bought a 71 GMC 1/2 ton 4x4 in April and have been fixing up the drivetrain from leaking on my garage floor.
It has a 4sp Sm465 Muncie trans and a NP205 transfer case behind a 454 that was installed at some point in its life. I am planning on pulling the trans and transfer case to reseal both. Two questions;
1) Is there a "standard" clutch diameter? I would like to have a clutch ready to change during installation.
2) I have had the trans crossmember out and it is only held in by four bolts on the bottom side of the X. When I tried to line it up with the top holes I could not get any bolts in. I assume this happened during the big block transplant. So while the trans and transfer case is out do I try to get this aligned and top bolts in or drill upper holes and install top bolts?

I use my truck as a driver and a truck, it is not a show piece but a cool old driver.
I would appreciate any advice you can lend.

[Stocker]

Afraid I can't answer your two questions, but lemme throw this in. You're probably replacing some seals, but if you're also replacing gaskets, I'd like to make a suggestion. Get some Permatex 81182. It's made specifically for gear oil applications. You can use it instead of gaskets, but I prefer using it with a gasket. I used it on both my differential covers and they sealed perfectly.

['68OrangeSunshine]

Originally Posted by Mryan

I bought a 71 GMC 1/2 ton 4x4 in April and have been fixing up the drivetrain from leaking on my garage floor.
It has a 4sp Sm465 Muncie trans and a NP205 transfer case behind a 454 that was installed at some point in its life. I am planning on pulling the trans and transfer case to reseal both. Two questions;
1) Is there a "standard" clutch diameter? I would like to have a clutch ready to change during installation.
2) I have had the trans crossmember out and it is only held in by four bolts on the bottom side of the X. When I tried to line it up with the top holes I could not get any bolts in. I assume this happened during the big block transplant. So while the trans and transfer case is out do I try to get this aligned and top bolts in or drill upper holes and install top bolts?

I use my truck as a driver and a truck, it is not a show piece but a cool old driver.
I would appreciate any advice you can lend.

Only answering Q #1:
I have a '71 GMC Jimmy 4x4 K/1500 w/ 350/465/205 stock OEM set up.
It has an 11" clutch. In '72 [iirc] GM went to a 12'' clutch. Someone retrofitting a BBC to a '71 may have gone with the bigger size, but you won't know until you pull it apart. I don't think there would be a problem with a 454 and an 11 inch, but bigger is better if you want no worries. If you do go 12 inches, you may need to source a BBC 12'' flywheel.
I used to run a '67 Chevy Suburban K/10, that a PO had put a 454 in front of a TH350/NP205. Sometimes the slushbox sweated big red drops, and it was hell on carrier bearings and universal joints, but it ran.