6066 (1960-1966) GMC Truck Club

6066 (1960-1966) GMC Truck Club (https://6066gmcclub.com/index.php)

- GMC V6 and V12 Engines (https://6066gmcclub.com/forumdisplay.php?f=9)

- - Project Blown 305 (https://6066gmcclub.com/showthread.php?t=49871)

Re: Project Blown 305

I'd like to stay manual, it's more fun and usually can handle a lot more as far as trucks go.

It's an SM 420 right now.

Now the part I'm concerned about is mounting a divorced Tcase setup as is have to create all the mounting and link the two together somehow I would assume with another driveshaft between em.

Re: Project Blown 305

Basically short of an nv4500, np435 or np420 I kinda am a noob to 4x4 transmissions.

Re: Project Blown 305

All the newer stuff has married transfer cases. Most manufacturers started marrying transmissions and transfer cases in the later 60's. I mentioned some exceptions in an earlier post.

GM went to left side (front axle) drive starting with the GM T400 trucks in '88. If you use a transmission/transfer case from one of those trucks, you'll have to use a Ford front driving axle if you are going to go with a straight axle. Somewhere a long the line, Dodge went to left side drive too (maybe '94?). My 97 Dodge has a Dana 60 front axle with left side drive.

Some GMC 305's had Chevrolet automatic transmissions behind them in the mid 60's, so sourcing the necessary parts would allow you to use a 700R4 or 4L80E Overdrive automatic behind your engine. The older 700R4's don't use a computer to control them (pre '94), so using one of those would be easy. 4L80E's are electronically controlled, so a stand alone controller is necessary (expensive), or there is a kit to make it a full manual shift.

The 700R4 can be built strong with aftermarket parts. The 4L80E is strong enough as is. Many 4 WD trucks came with these two transmissions, so finding one with a transfer case attached is easy depending on where you live. (they are all over up here in the snow belt)

Re: Project Blown 305

Interesting, I'm aiming for a manual.

I'm okay with a divorced or married one although married would be simpler overall.
Initially I hadn't though about doing it that way.

I did find a Dana 60 front from a Ford F-350 from the 70's.
That probably would be better than the 10 bolt I have but I don't know much about closed knuckle front axles.

Re: Project Blown 305

Dana 60 is the strongest. I prefer the closed knuckle axles as the axleshaft u-joints run in gear oil and are protected from outside contaminates. The closed knuckles disappeared when disc brakes were installed. (at least with GM)

Re: Project Blown 305

Ah gotcha, I may have to consider it then since it's really cheap and at this stage the only real downfall is I'd have to hope Fords frame is the same width haha.

Bigblockv6 I didn't realize you're relatively nearby.
Pretty cool!

Re: Project Blown 305

Quote:

Originally Posted by Cuttyman9 (Post 66464)

at this stage the only real downfall is I'd have to hope Fords frame is the same width haha.

It is. These old ones are all 34" frame rails.

Re: Project Blown 305

Interesting, guy claims it's a 74 closed knuckle drum

So long as it's able to be converted to disc I don't care if it's from something else.
I may run a divorced T case so if that's the case I should be able to find a driver side drop.

http://i1307.photobucket.com/albums/...psi1pgvtmi.jpg

This would prolly suit the build far better cuz I was thinking if this turns out to be a blown 478 even it's going to put enough torque to hurt just about any front axle.

Re: Project Blown 305

If your going the divorced route and pass drop you have a few option. The New process 200 from the 50s dodge power wagon is a good case and not to hard to come by. Also GM used a New process 205 that is good. They are both gear to gear cases with a 1.96 low range. If you want to go divorced and drivers drop your only real option is a ford New Process 205 but they are hard to find and harder to find hard parts for.