82 C10 250 six to 350 V-8 swap

[MikeB]

Hey guys, what's required from a motor mount and trans mount standpoint to install a 350 V-8 and TH350 trans in place of a 250 six and 3-speed manual trans?

 

[bucket]

Trans should swap right in. Pretty sure you just need the small block mount brackets to swap the motor in.

 

[MikeB]

Here's what I've learned since starting this thread: For 81-82 C10, C20, C30 trucks, the frame brackets are the same for a 250 six and 305/350. P/Ns are 464710 (left) and 6271361 (right). However, the motor mounts must be bolted to the upper holes on the brackets for a 305/350, and the lower holes for a 250 six.

As for the engine brackets (aka clam shells), for a 79-84 C10 (not C20 & C30) the P/N for 305/350 engines is 334601 for both sides. While all the clam shells look similar, there are at least 4 different P/Ns that I've found, all with different distance from block to motor mount hole. K model trucks, for example, use a clam shell that's approx 11/16" shorter because there's a trans support plate under the clam shell.

FYI, in the parts books, the frame brackets are called "BRACKET, ENG MT FRM". The clam shells are called "BRACKET, ENG MT".

I used GMParsWiki.com to find the part numbers.

Oh, yeah, TH350 overall length and crossmember mounting is the same as a Saginaw 3-speed + bellhousing.

Whew!

 

[foamypirate]

Here's what I've learned since starting this thread: For 81-82 C10, C20, C30 trucks, the frame brackets are the same for a 250 six and 305/350. P/Ns are 464710 (left) and 6271361 (right). However, the motor mounts must be bolted to the upper holes on the brackets for a 305/350, and the lower holes for a 250 six.

As for the engine brackets (aka clam shells), for a 79-84 C10 (not C20 & C30) the P/N for 305/350 engines is 334601 for both sides. While all the clam shells look similar, there are at least 4 different P/Ns that I've found, all with different distance from block to motor mount hole. K model trucks, for example, use a clam shell that's approx 11/16" shorter because there's a trans support plate under the clam shell.

FYI, in the parts books, the frame brackets are called "BRACKET, ENG MT FRM". The clam shells are called "BRACKET, ENG MT".

I used GMParsWiki.com to find the part numbers.

Oh, yeah, TH350 overall length and crossmember mounting is the same as a Saginaw 3-speed + bellhousing.

Whew!

Nice detective work there, sir!