Projects 1959 GMC truck v8 mounts/conversion help needed

I have a 1959 gmc 150 3/4 ton. I did my research and found the front motor mounts hopeful for a pontiac 336 to sbc motor swap. When they came in I realized that my cross member that these should bolt to share nothing in common with the factory motor mounts and do not bolt up as it seems like they should from various threads/ photos. My cross member does not even share the same holes/ slots and design as the other cross members that i see online. It did have a factory I-6 and then later had a pontiac added. Anybody know whats going on and what are my best motor mount options?

I have attached my cross member first, with what seems to be the normal style after.

 

you have two pics, one is probably your truck???? the other is a Chevy truck. Chevys have different front crossmembers than GMC trucks. they used different engines, with different mounts.

If you just want to put a Chevy V8 into your GMC, get a universal crossmember that goes under the engine, using the mounts on the sides of the block. For the rear, what to use depends what type of transmission you plan to use. If it's manual, get a 55-59 or 63-72 Chevy truck bellhousing, it should bolt into your truck. If automatic, use a universal rear transmission crossmember.

TransDapt makes those universal mount crossmembers, among others.

 

squirrel is 100% correct. However you can use the chevy truck bell and fabricate some front engine mounts that attach at the very front of the engine. That way there is nothing on the side of the engine to interfere with hedders or exhaust manifolds & pipes ect. I have a 56 3/4 ton chev in my hoard that has that V8 crossmember. It would be possible to chisel off the rivets and bolt it on a GMC frame.

 

That picture looks familiar to me LOL

 

GM used a horseshoe shaped front mount bracket in their
c/40, c/50 etc medium trucks in the '60s era that were cheap
new and I used them for putting various small blocks in early '60s
Chevy pickups. It uses the same 4 tapped holes in the front of the
block that Hurst type mounts use. Don't know whether that helps
here but thought it might be worthwhile trowing into the knowledge
pool.

 

Wow, I have never heard of that type mount. A "Learn something every day" thing.

 

I know where a Chevy crossmember is in Minnesota if you are interested in swapping out crossmembers, send me a p.m. if you are.