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so i need a drioveshaft that is 75 inches long, i two differnt local shops and one said that wouldnt do a 1 piece that long, that its critical speed would be to low for me. the other said that they would do it and it would be fine. anybody have experiance doing something this long?
 

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Assuming it isn't already built I would suggest most likely doing a two piece in a situation like this. What's the application?

-Matt PST
 

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I know this is a older thread---

But 60" or longer in length requires a 2 piece shaft..... Otherwise the shaft becomes a jump rope when the RPM's come up.
 

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Many who have raced 1965-70 full size Chevys experienced drive shaft failure at the top end.

I busted 2 and discovered it was a very common problem as the shafts were about 62" joint to joint.

I had one built that lasted but as mentioned 75" would be way too long.

Afterwards I thought a long tailshaft T-400 might have been the solution, Chevy did from 1971-76.

Each time the driveshaft busted it also busted the trans case.
 

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^^^ that's what I like about this place !!! real world experience :) I wanted to put a short Powerslide in my 65 Impala , instead of the long 400 .



What type of hangar bearing ? Will a stock 1 ton style rubber mounted work ? ...Trevor
 

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All 65-70 Impala trans were the "short tailshaft" versions from the factory, do you have a long tailshaft 400?

A short 400 is slightly longer than a short P.G. or T-350 but there are longer versions available for all.

T 400 trans cross member tabs were welded to the frame in further back than the others.

1965-70 factory T-400 Impala frames usually have 2 sets of cross member tabs.

I would use a long version of whatever trans I was running to be able to use a shorter driveshaft.

There were long P.G.s but they are probably scarce now.
 

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Already have a fresh glide with a good convertor , it's a race car , trans mount is modified . Don't remember seeing long Powerglides only long 400's in late 60's Buicks , Olds ?
 

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The long P/G's were in full size Chevy cars, 1971-72 and maybe 1973.

Probably hard to find a core these days, maybe a Demo Derby guy saved one.

All the 1971-76 full size chevy cars had a long trans, PG, T-350 & T-400 as well as some pickups and vans (TH350)

My car was full bodied and ran 12.0 as that was the limit for no bar/cage at the time.

As mentioned, I twisted 2 stock shafts, 1 used, 1 new, at the top end going through the lights.

I had a new one custom built for this car/purpose that gave no problem, 62" from memory.

Center bearing set up from a T-350 pickup or van should do the job nicely.

Post up some pics!!

 

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:cool: Strato Chief ?
Got the car up and measured , 400 trans in car is about 28" long , mid length ? stock out of 89 Suburban .
The powerglide measures about the same , my mistake i thought it was shorter :)

2 Driveshafts measure 56" and 57" . The shorter one is Aluminum out of an Aerostar van , and yes it works fine ! ( conversion joints )

So it looks like I will be OK if I can find an output yoke a couple of inches longer to fit the Powderslide .

Car is a 65 Impala 4,000 lb. Wagon 454 ran 12.2 at 110 last week . http://classracer.com/classforum/showthread.php?t=51016

Previous owner talked of shaft carnage , floorpan damage near the rear joint bears witness ;) ...Trevor
 

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75" is too long for a 1 piece I cant see that working out except perhaps in carbon fiber , look up some critical speed charts.

Even if it is a T400 and the longer tail is installed (trans tear down) you'll only get it back to 70" with the 9" full size chevy end, and 67" with the cadillac 12" end.... still a very long driveshaft.

(the typical most commonly used T-400 has a 4" tailshaft vs the 9" full size chevy and 12" cadillac end )
 
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