Drive Shaft Length w/ 700R4

[LTZ C20]

I'm working on building a new transmission for my truck. I have a 79 std cab long bed c20. Some of you know I recently got a new engine. Well now I'm working on building a new 700r4 because I broke the old 350 I had in it.

I'm looking at getting a one piece drive shaft for the truck. I have a 2 piece currently. A local auto machine shop gave me great prices on shortening the 2 piece, adding new u-joints and center bearing. I called them again and they needed some measurements to give me a quote on the 1 piece shaft.

Does anyone know what the length from center joint to center joint is on a single cab long bed 3/4 ton 2wd. They say pull the slip yoke out so you have about an inch or so of slack in the yoke to output shaft on the trans, then measure center to center.

I don't have the trans finished yet so it's not in the truck so I can't measure it. Any ideas were to look or measurements from past jobs of the same type? Thanks everyone.

[Irish_Alley]

what size th350 did you have 6,9 or 12". the 9" is about the same size as the 700r4 about 31"

[LTZ C20]

I have no idea. All I know is that it's an old 350

[Irish_Alley]

meant to say its the tail shaft housing on the th350s. ones 6" ones 9" and the other is 12"

[LTZ C20]

Oh ok. I was about to say I measured the whole trans last nite. Came out to 31 1/2 or so. I'll measure the housing when I walk past to leave this morning.

[LTZ C20]

The tail shaft housing measured as the 9" one.

[bake74]

     I would suggest you wait till you do have the transmission in and can measure.  Small things can make the differences on measuring drive lines.  I know a inch or so will not kill you on a 2wd but, anyway that is just a suggestion.

[Irish_Alley]

If your th350 is the 9" one they should be about the same. I think your good

[LTZ C20]

Ok cool guys. Thanks. That gives me a ruff number to give the machine shop for a quote. I'll measure the actual after the trans is in so they can build it.

[Irish_Alley]

the 700r4 is 30.75" and the th350 is 30.6875. i mean if you want to get a new shaft go ahead but you wont need it
this should help convince you
http://www.tciauto.com/tc/trans-dim/

[LTZ C20]

Thanks. Yea, it's not really a need. It's a want. I think it looks better with a one piece shaft instead of two. No center bearing, less parts to fail.

[Irish_Alley]

lol ok

[Captkaos]

You need to get it in the truck before you can measure.  They should have a formula to get you the right shaft.  It should be from the end of the trans shaft to the flat part of the cap and they need to know how far the shaft extends past the tailhousing...

[LTZ C20]

Oh ok. Well I'll know more tomorrow after I call back to give them measurements.