I am changing out the driveshaft..CHROMOLY STEEL OR ALUMINUM??

[biomedtechguy]

I was looking hard at Strange, because I saw a chromoly steel shaft at what I thought was a reasonable price.
The driveshaft I have now is the one that came in my 70 Roadrunner, but I'm certain that it is NOT the original driveshaft, as I had to have it shortened slightly and rebalanced. My forum family helped me find the problem I had been having since I bought my car, a bad vibration on the highway. It was yet another 8¾ driveshaft from a B body put in a Dana 60 equipped car without being shortened to the correct length for the Dana 60.
Anyway, I've dealt with the driveshaft shop I brought it to for years, and the quality of their work is top notch. He said my driveshaft looked like a "backyard hack job" so it wasn't "all that nice" to begin with.
Anyway, while the car is in the shop, NOW is the time for me to upgrade to the appropriate driveshaft to handle the much higher RPMs that my 4.10 ring and pinion gearset AND .70 overdrive 5th gear bring, the stress that the launch control, higher RPM launches, and Assassin traction bars will bring, PLUS the appx 675HP and 700 ft lbs of torque I'm expecting to get from my 541 stroker build, and I may put another 150 HP on top of that in the 2nd half of the 1320 if I spray a bit to make a close L into a close W.
Regardless, my engine builder suggested I look here:
http://www.fastshafts.com/
He said that he has used their products a LOT on circle track cars.
Anybody familiar with FastShafts?
Other companies?
Material recommendations?
Chromoly steel?
Aluminum?
I'm afraid to price carbon fiber, and I'm going to be driving on the highway and cruising all around on all kinds of roads, so I'm also a little concerned about the durability of a carbon fiber shaft what with road debris, rocks, etc. but I certainly would consider carbon fiber too!
Talk to me!!

 

[Norwoodville Speed Shop]

Great company. Talk to Pat and he will take good care of you.

 

[biomedtechguy]

Great company. Talk to Pat and he will take good care of you.

Thanks, I did, and he quoted $700 for a 3½" diameter chromoly steel driveshaft with a new forged 1350 manual transmission slip yoke and 1350 U-joints. I already bought the Strange 1350 pinion yoke and caps.
I'm going to have to look at critical RPM range by doing some calculations. 4.10 R&P gears spin that driveshaft really fast, especially with my current 26" diameter tires.
ALUMINUM or CHROMOLY STEEL?

 

[Endangered Species]

Both are good... but I would go aluminum if I had it to do over again.

Either way you won't notice anything in ET difference.

 

[440ronnie67]

I have a 4 inch aluminum,1350 u joints. Itp in Austin texas made it . No problems and light. It was about 600.

 

[biomedtechguy]

I have a 4 inch aluminum,1350 u joints. Itp in Austin texas made it . No problems and light. It was about 600.

Thanks
I let the guy who is doing my stroker build know that I was ok with FastShafts, and he is going to contact them Monday..
BUT
I have one more really SOLID connection and I want to see what they offer in chromoly steel and also aluminum. If the strength of aluminum is in no way a compromise or potential problem, as long as it fits (I'm a little worried about, say, a 4" diameter maybe ? causing interference problems?) I would prefer aluminum if there is NO downside vs chromoly steel.
So thanks for all the help and advice, for my questions and the OP and others who participated.
Before the new rear suspension components are installed so the exact measurement can be taken for the driveshaft, I will have my source lined up and ready...
THAT is how I hope my stroker build will go, and that's the best way to move forward with any project as far a I'm concerned. Less stress and a better outcome, PEACE OF MIND!

 

[biomedtechguy]

Looks like Strange 3" chromoly steel driveshaft is the ticket.
7,500 RPM critical speed will get it done, and at $544, including a chromoly slip yoke and 2x 1350 solid U-Joints, balanced and ready to install, everyone else was $700-$800

 

[biomedtechguy]

 

[440ronnie67]

Looks like Strange 3" chromoly steel driveshaft is the ticket.
7,500 RPM critical speed will get it done, and at $544, including a chromoly slip yoke and 2x 1350 solid U-Joints, balanced and ready to install, everyone else was $700-$800

Great price and super strong

 

[biomedtechguy]

Driveshaft:
https://www.strangeengineering.net/...ome-moly-driveshaft-with-h-d-u-joints-2.html/
Slip yoke:
https://www.strangeengineering.net/...par-etc-30-spl-1350-strange-chrome-moly.html/
U-Joints:
https://www.strangeengineering.net/product/non-crossdrilled-h-d-u-joint-1350.html/
Just like the pinion yoke, their products have a look and feel of precision and strength.
I'm excited!
I have to say again too, the Assassin bars are really top notch!

 

[70chall440]

You might take a look at these guys, I had them build me a 4" aluminum shaft for my Cuda, good price, quick delivery and very nice product.

http://www.driveshaftspecialist.com/

 

[biomedtechguy]

You might take a look at these guys, I had them build me a 4" aluminum shaft for my Cuda, good price, quick delivery and very nice product.

http://www.driveshaftspecialist.com/

Thanks. Their pricing was comparable to Strange Engineering, but they have an 8 week order to shipping time. Nice enough on the phone, knowledgeable, but with all the calls I've made or had made on my behalf, and the websites I've visited, "critical RPM" calculators I've used, and a LOT of feedback from forum friends, some of whom have Hemi powered street/strip or all out race cars, I'm 100% confident in my quote from Strange.
Here's something I think many of you can relate to...
Even though it's going to be a month or more (or maybe less-the shop owner has really "taken" to my car, made it personal, or as he said 'fallen in love with' my car) seeing the Calvert split mono leaf springs and sliders and Assassin traction bars on the car, and talking with him about what he is planning on doing next, and how if he sees a mix-mash of nuts and bolts that can all be one kind (something I've been working toward and gradually "fixing") he's going to replace them with nice, appropriate materials and strength hardware...
I'm EXCITED, and that's always a good place to be, especially when it comes time to pay up.
He actually quoted me a price before he started, but after he laid everything out and discussed the details of what's involved and did his own research and reviewed the manuals etc. I ran "the list" of what's being done by 2 very very close friends who still wrench on their muscle cars, guys I've been tight with since we were teenagers, and they were in the same ballpark, one a little lower and one spot on the quote he gave me. I asked for a $1K discount if I paid half in cash, we shook on it and away he went to work on it. When he brought up subframe connectors, I said that I've been planning on getting them but I really couldn't afford to add to the labor bill. He said to order them.
That's just one of several important reasons why he gets my return business on my car and the GTO, which he did a lot of work to. Guys like him are getting harder to find.

 

[Hemirunner]

Carbon Fiber.... if you’re gonna go, go all out!

 

[biomedtechguy]

Thanks, but no...
For one thing, CF is a larger diameter than 3¼, and that would require an exhaust system rework. I'm also concerned about an impact from the side by road debris shattering or cracking the CF, and lastly, I'm hemorrhaging money, and I still have other things to pay for, so no reason to double the cost of the driveshaft.
I am looking for a taller cowl version of my hood in CF though. Depending on how much it costs, like my paint and bodywork guy said he thinks he can get me a CF hood at $1,500, that is the cost of a fiberglass hood and the paint job to match, so basically the same cost, and I think that a natural CF finish hood (maybe with the factory satin black stripes) would look AWESOME on my car, and add to the unique "restomod" theme I'm loosely following.
This finish: