Re: Longbed driveshafts
 

Good to hear! 250 sounds like a good price. 4" shaft fit through the factory cross member okay?

Re: Longbed driveshafts
 

I guess Im not sure which crossmember you're referring to.

https://i.imgur.com/cIUT5PSl.jpg

dont mind the mufflers. Im replacing the other and have to have my crossover pipe rebuilt.

Re: Longbed driveshafts
 

Didn't realize you were on a different rear suspension, I thought you were on a trailing arm set up like on my 65'. This is the cross member i was referring to ....edit, not my truck just a pic found off google
http://image.trucktrend.com/f/315787...ailing_arm.jpg

Re: Longbed driveshafts
 

Well bumping this thread up for the tumble weeds to blow through LOL.

Anyway I'm changing my setup again and will be playing the driveshaft game late in the spring but have already been doing up some research as I knew it was going to be a run around.

New motor will be in the honest 1200hp range N/A, plus will still have my nitrous on it for play if I want, good for up to 200 shot but setting up to run mostly N/A. Going to a SFI case turbo 400 but going to give a long stock tail housing a try to get my driveshaft length down, only downside to that is will have to run a bushing instead of a roller bearing.

I'm thinking that it should run high 8's on motor, going to put in a 4.57 rear gear, and current tires are 32.3" tall, next set will be 33" both listed with a 102" roll out. Motor will spin 8000, if need be, builder figures a guy will be shifting 7800, with convertor slippage and such and a big safety margin I'd say using 7800rpm for critical speed of the driveshaft through the traps should be more than good as doubt I'll ever see close to that unless I drop rear gearing more yet, right now calculating that center to center on the shaft should be ~ 65".

With all that the calls began, all choices and options point to a CF with only one shop claiming a 5" aluminum would work, most CF shaft makers either can't do a 5" or can only handle a 60-61" max tube length. Still waiting on a couple calls/emails back from one place that initially thinks from past projects they could get it done with a 4" CF but are now doing military contracts and won't change tooling for a one off at this point in time, but late spring could be different.

Anyway I look at it unless the 5" aluminum that one place claims would spin 8000 (sounds high to me and the one calculator I found online, do believe it was DOM .125" tubing), will work, I'll be stuck with a custom 5" CF that is rated 8551rpm, with a nice price tag of ~ $2025 plus trans yoke and shipping.


To be continued...…...

Re: Longbed driveshafts
 

Two piece driveshaft with HD carrier bearing and 1350 ujoints.

Re: Longbed driveshafts
 

Wow! It sounds like you're stepping things up quite a bit. Glad to hear that. That should be a lot of fun!
I'm wondering if a custom 2-piece could be built to live behind that combo. I know it adds a couple more possible breakage points, but, if everything is sized correctly, I wonder if that might be a little easier on the wallet. A 2-piece is definitely a bigger pain to work with, but might be a more affordable option.
Again, just throwing an idea out there. Good luck with it, whichever way you go with it.

Re: Longbed driveshafts
 

I already had my chassis guy modify my loop and 4-link crossmember to a fit a 5” carbon fiber shaft. I know price is high, but they are way lighter and a lot easier on the center section and trans if the shaft ever does let go, both of which are pricey too, not to mention risk of coming through back of the cab.

A tougher 2 piece would definitely be a option, farm truck runs one, and I have one now that could be built tougher, but I’m going to bite the bullet and go carbon fiber. Guess we will see if it is a wise investment or not.

Re: Longbed driveshafts
 

You make some good points about the safety aspect of a hd 2-piece. I hadn't thought about the front shaft wacking the back of the cab in the event of breakage in that area. I did install another d.s. loop just behind the trailing arm crossmember for the front of the rear shaft, but that would only contain the front of that shaft in the event of a failure. A 1-piece would definitely eliminate those particular issues. Along with the added bonus of less weight.

Re: Longbed driveshafts
 

There are driveshaft length and diameter formulas on the web. Use them. I was uneducated about driveshafts years ago and found out what critical rpm means on a driveshaft. It cost me a full exhaust and a TH350. Split the trans from front to back. And made a lot of noise at over 120.