Replacing TH350 with a TH400..will it bolt in 73?

73TurboNova · 24th-October-2008, 09:32 PM

I am replacing a TH350 with a TH400. As long as I get a short tail housing, will it bolt in other than replacing the transmission yoke? Is the length the same? I am mainly wondering if I can use the stock driveshaft.

Thanks

tvnl · 24th-October-2008, 11:09 PM

Nope it's longer.

73TurboNova · 25th-October-2008, 12:37 AM

Quote:

Originally Posted by tvnl

Nope it's longer.

Doh! I guess the fact that I got one with a 9" tail housing doesnt matter then, its a custom driveshaft either way. Hopefully Dennys has fast turn around, I'll give them a call on Monday. Might as well upgrade to 1350 ujoints too. Thanks

**1quik69** · 25th-October-2008, 02:13 AM

You'll need the TH400 crossmember,Th400 yoke and a different length driveshaft.

firebird69racer · 25th-October-2008, 03:14 AM

Make sure you get the right O.D. yoke to go with the tail housing seal and bushing. There are two different sizes.

tvnl · 25th-October-2008, 09:15 AM

Quote:

Originally Posted by firebird69racer

Make sure you get the right O.D. yoke to go with the tail housing seal and bushing. There are two different sizes.

I've never run across that, if so i would think it would be the bolt on yoke that would be bigger cause that's what they used in the big trucks.

balljoint · 25th-October-2008, 01:33 PM

Why do feel the need for a turbo 400,your 350 can be built as strong as you want ,and is lighter.

73TurboNova · 25th-October-2008, 05:11 PM

If I dont mount the motor offset, can I just scoot the crossmember back and drill new holes in the frame, or is the TH400 mount a different height too?

The reason I am going with a th400 is I am putting a single turbo 454 in the car so it needs to support alot of power.

Thanks for the help.

**1quik69** · 25th-October-2008, 05:46 PM

I'm not sure if the mounting height is different but the TH400 crossmember is completely different from the TH350 crossmember. The TH400 member will bolt right to the factory frame holes. Run a search on e-bay or google and you will see what I mean. The aftermarket catalogs will probably show them also.(Classic, year one etc)

Tony Silva · 3rd-November-2009, 04:21 PM

you guys answered my questions, lots of knowledge all over this site

Dutch · 3rd-November-2009, 05:33 PM

Quote:

Originally Posted by balljoint

Why do feel the need for a turbo 400,your 350 can be built as strong as you want ,and is lighter.

I agree here, cant think of much a 350 cant handle. With everything that you will need to convert to a 400 why not just put that money into building a stronger 350??

73TurboNova · 3rd-November-2009, 05:47 PM

Quote:

Originally Posted by Dutch

I agree here, cant think of much a 350 cant handle. With everything that you will need to convert to a 400 why not just put that money into building a stronger 350??

Its cheaper to build a TH400 to take 800hp than a TH350 or Powerglide.

I got the TH400 in last month. I bought a new crossmember from Ebay (thanks China) and reused my stock driveshaft, all I had to do was change the transmission yoke, the length was fine. The short TH400 is about an inch longer than the TH350 so there was enough room. Im going to convert to 1350 ujoints and get a new driveshaft anyway but it was nice to get it up and running right away with the stock shaft.

Dutch · 3rd-November-2009, 06:47 PM

For the u-joints have you heard of CTM? I have heard good things but wondered if you had seen or heard of them, might be a good choice for your set-up.

photoman · 3rd-November-2009, 07:45 PM

Be sure to use a driveshaft loop. You're going to need it putting 800hp to a stock driveshaft (assuming you get some traction).