700r4 drivehsaft question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

c20pickup · 01-17-2014, 03:34 PM

after swapping my 700r4 for my th350 I have read I need to have my driveshaft shortened, in the future (before the truck is on the road) I plan on swapping the rear end, currently an Eaton, for a 14b ff or a Dana 60. am I able to have a one piece driveshaft built? im assuming with the new rear end and transmission id be better off building something from scratch instead of modifying my two piece. id rather eliminate the carrier bearing and the two piece driveshaft, has anyone done this? any advantages to the one piece? dis advantages? would the driveshaft angle be improved because the first contact point (uJoint) is farther away? (hopefully that made sense). some help would be great. im assuming id have to modify the cross member in order to run the one piece. the truck is a 1970 c20 lwb with a mildly built 350.

**425HP409** · 01-17-2014, 05:20 PM

If your TH350 has a 9" tail shaft, you will not have to do anything to your driveshaft, however if your TH350 has a 6" tail shaft, you will have to shorten your driveshaft by 3". I would keep the two piece driveshaft, it has worked for 44 years....and it will be a lot less problem using than having to modify your driveline.

Z10 · 01-18-2014, 01:07 AM

Just swapped a 350 for a 700r4. The truck had a one piece drive shaft which I shortened about 3 inches. Cost me $160 which included new heavy duty ujoints.

c20pickup · 01-19-2014, 11:08 PM

Quote:

Originally Posted by Z10

Just swapped a 350 for a 700r4. The truck had a one piece drive shaft which I shortened about 3 inches. Cost me $160 which included new heavy duty ujoints.

was the truck lwb or swb?

c20pickup · 01-19-2014, 11:08 PM

the truck had a short tail shaft, probably the 6 inch one your talking about.

01-17-2014, 03:34 PM	#1
c20pickup Registered User Join Date: Apr 2013 Location: Brighton, WI Posts: 504	700r4 drivehsaft question after swapping my 700r4 for my th350 I have read I need to have my driveshaft shortened, in the future (before the truck is on the road) I plan on swapping the rear end, currently an Eaton, for a 14b ff or a Dana 60. am I able to have a one piece driveshaft built? im assuming with the new rear end and transmission id be better off building something from scratch instead of modifying my two piece. id rather eliminate the carrier bearing and the two piece driveshaft, has anyone done this? any advantages to the one piece? dis advantages? would the driveshaft angle be improved because the first contact point (uJoint) is farther away? (hopefully that made sense). some help would be great. im assuming id have to modify the cross member in order to run the one piece. the truck is a 1970 c20 lwb with a mildly built 350.

01-17-2014, 05:20 PM	#2
425HP409 425hp409 Join Date: Oct 2008 Location: Prosper Texas Posts: 841	Re: 700r4 drivehsaft question If your TH350 has a 9" tail shaft, you will not have to do anything to your driveshaft, however if your TH350 has a 6" tail shaft, you will have to shorten your driveshaft by 3". I would keep the two piece driveshaft, it has worked for 44 years....and it will be a lot less problem using than having to modify your driveline. __________________ Charles 68 SWB, Dad bought new, now 396 & factory ac 64 Impala SS, 409 425HP, 4 speed AC 64 Bel Air Wagon, 400 Small Block 57 Bel Air all original 283 w/Factory Air 77 GMC Sprint, 454/425HP 67 Olds 442, all original 90 ZR1 Corvette

01-18-2014, 01:07 AM	#3
Z10 Registered User Join Date: Aug 2012 Location: Midland, TX Posts: 1,267	Re: 700r4 drivehsaft question Just swapped a 350 for a 700r4. The truck had a one piece drive shaft which I shortened about 3 inches. Cost me $160 which included new heavy duty ujoints. __________________ 1969 RS/SS Z10 Camaro Pace coupe 1972 GMC Short Step buildhttp://67-72chevytrucks.com/vboard/s...=1#post6356218 1979 Mazda RX7 1979 Pontiac Trans Am WS6 & 1979 Pontiac Trans Am 10th Anniversary 1999 Honda Valkyrie 2006 Corvette Z06 2010 BMW 650i

01-19-2014, 11:08 PM	#5
c20pickup Registered User Join Date: Apr 2013 Location: Brighton, WI Posts: 504	Re: 700r4 drivehsaft question the truck had a short tail shaft, probably the 6 inch one your talking about.



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