Anyone using a (re-sized) V6 driveshaft with a big block engine?

[454GrandPrix]

Of course I'm going to need to get a different length driveshaft for my drivetrain swap. My car was a 231 V6, and I'm installing a big block 454 (with 4L80E). Having my stock driveshaft shortened and balanced is easy to do... but would that be wise? Can that size/strength of shaft stand up to 500+ lb ft of torque? I'm thinking not.

If anyone out there has swapped in a big block V8 and kept their (modified) V6 driveshaft, I'd love to hear about your experience (good or bad). Please speak up.

 

[565bbchevy]

I wouldn't waste time spending money on a stock driveshaft, a custom made one can be designed from the start to handle the power level you desire.

 

[Texas82GP]

Check out Denny's Driveshaft. We used them on my brother's 78 Z28 LS swap and it was a great experience.

http://www.dennysdriveshaft.com/

 

[Opie Knievel]

I agree with 565bbchevy, if you're already replacing the engine and transmission you might as well get a driveshaft made specifically for your application. I'm sure a stock one would hold for a while but it'd be a good idea to eliminate any weak links that you can.

 

[565bbchevy]

Also make sure you have at least a front driveshaft loop, I installed both front and rear on mine the rear one I made so it unbolts easily to get the driveshaft out.

 

[Opie Knievel]

I had my dad cut, shorten and re-weld a driveshaft for me on an 83 Monte Carlo once. He didn't have any special tools and no way to balance it. He told me that he wasn't sure if it would even work without vibrating at speed and to take it easy on it. Well I was about 21 or so at the time and I had faith that dad could fix it if anybody could. Lol. Plus, my friend and I really wanted to get the car back on the road.
We put the driveshaft in and my friend and I decided that if it was gonna break, we should find out as soon as we could so we wouldn't have very far to walk. Lol. As soon as I got on the road I floored it and it actually stayed together. We were pretty happy so we took it up to about 100mph just to make sure there weren't any vibrations. It never had a problem. We used that driveshaft for a while. We also only had about half the torque and horsepower that you're planning on making.
There's no way I'd want to try that again! Lol.
We got very lucky.

 

[Opie Knievel]

Also make sure you have at least a front driveshaft loop, I installed both front and rear on mine the rear one I made so it unbolts easily to get the driveshaft out.

Agree x2!! The rear U-joint broke on my truck the other day. I didn't have a driveshaft loop and the driveshaft beat the hell out of my poor truck before I could get it stopped. It put a big dent in my brand new gas tank. It could have been worse though.

 

[JBreu]

I'd get a new one built, they aren't that expensive. I got mine built at Fleet Pride....They are a franchise, I bet there's one neay ya

 

[454GrandPrix]

Yeah, the best driveshaft shop in the county is only half a mile from my work. Having them fab one up from scratch would be very easy, and I know they'll produce a quality product.

Another option for me would be to pull the driveshaft from my donor Express 3500 van and have it sized for my application. If it is sturdy enough for a one-ton van, I would hope it would be sufficient for my car.

As far as driveshaft loops go, I definitely think they are a wise idea. I've already noticed that there is one effective loop built into the car, up next to the transmission. Do all the G-bodies have that? (I would still want to add another one near the tail end.)

 

[565bbchevy]

I felt the factory sheet metal "loop" was questionable at best so I removed it and welded in mounts in the same location and used a universal loop made out of 1/4" steel, I used the same style for front and rear I just have it opened more on the rear for suspension travel.