trans swap 700r4 to th350

[jetman373]

I recently bought a 84 gmc,305,700r4, long bed 1/2 ton, 2wd. The 700r4 was bad,so I replaced it today with a th350 from my 70 chevelle. The trans crossmember is different and the driveline will need to be longer cause of the short shaft trans.My question is,what years do I need to look for for the crossmember, and did they ever have short shaft 350's in a londbed? Hope I dont need to have a driveline made for it.Thanks for any advise!

[roundedline]

short tail as in 6" or 9"?
You don't need a new crossmember, just move it forward 2"  so the trans will bolt up.  TH350's were availible all the way up to 1987 and they use the same crossmember.

You will HAVE to get a 3" longer driveshaft if we are talking about a 6" shorttail.

Chris Lucas
www.73-87chevytrucks.com
www.captkaoscustoms.com
Project Su
Jimmy 2WD Project

[jetman373]

I have a 6 inch tailshaft. I was told today that they never put a shortshaft in a londbed. Is that true? If so, Im going to have a driveline custom made. The mount for the 700r4 has a stud comming out of the bottom where my 350 mount has two bolt holes.I tried the 700 mount on the 350 and no go.Is there a mount for this,or should I drill 2 holes in the crossmember? Thanks for the help!

[roundedline]

1 piece or 2 piece driveshaft?  Most were 9" tails.
The 700R4 mount should bolt to the TH350, what was not fitting?

Chris Lucas
www.73-87chevytrucks.com
www.captkaoscustoms.com
Project Su
Jimmy 2WD Project

[jetman373]

It is a 2 peice driveline.The 700 mount has a wider bolt location than the 350 where it mounts to the trans. I think I can use the front half of a 2 peice driveline from a short shaft short box along with my long rear to solve my driveline issue?All I should need is a 350 yolk. Think Im on the right track? Thankyou!

[Blazin]

Save yourself some hassle and have a one piece shaft made.