Differential yoke question

[meepbeep69]

I was just wondering if a 7260 rear will be stout enough for some 440 torque.

Flywheel measured 494HP @ 5400 with smaller headers at the dyno shop. Torque was in the 540 range throughout falling off at 5700. 3.91 fresh rear 4 speed A-833 23 spline with show, cruise and hamburger stand thoughts in mind.

There is a Mopar Ford shootout so my son will race me in my '04 Cobra ragtop. That is about the only time it will see the track.

I need to order a driveshaft so now is the time to either go with the 7260 or ditch it and make a change. Some of the A-body guys I know say it is fine ( they are running quicker but lighter)

There is the one guy on here with the dart and the Pratt & Whitney pt-6. He has a 7260 right?
http://en.wikipedia.org/wiki/Pratt_&_Whitney_Canada_PT6 (1920 shaft horsepower) Man I miss my old aviation job!!

Actually he is the guy with the 440 Dart twin turbo. Just a ride in that and I might foget about a dual ride in a P-51 or F4U Corsair.

I will be swapping my valve covers to the 69 style. Have to borrow them from my other block.

What does the B body crowd think?

I hope I can get away without doing anything special on the driveshaft.

Oh, 22570 or 75 15 tires on poverty steels to start.

In the paint booth today!!! :banana: :worship:

Anybody within driving distance of Chicago with an extra driveshaft?

Will let you know if the hood closes with the drop base and unsilenced air cleaner in a few days.

 

[moparchris]

In my experience it will work fine. I would have second thoughts if you were running slicks and dropping the clutch at peak torque WOT. Since it will have non sticky street tire you wont be able to strain the u-joint. Pinion angle will kill a u-joint fster than anything so make sure that the car is close to stock height with stock leaf spring perches and a pinion snubber. That should be it. Good luck I cant wait to see the results.

 

[SomeCarGuy]

My car has the 7290 to 7260 conversion joint and it lived fine behind a mild 440. Not near what you have there though.

Life is really easy on it now with a 383 in front :acme:

 

[meepbeep69]

That pinion snubber looks like it belongs in a Cushman!

Thanks for your help.

Is the larger driveshaft with the 7260/7290 ujoint the way to go?

I think by the time I find one and have it shipped I might as well just have one made around here by some "mopar friendlies".

Buddy at the shop says there is a lot of green paint on this thing. Too humid to hit it today with the V-21 paint.

Mcmopar what are your thoughts on the driveshaft?

 

[Basketcase]

I had the conversion joint in my other car, 440 4 speed 3.55sg, with no problems.

 

[meepbeep69]

Basketcase.

Did you know that you gave that tire iron to a U of M grad? It cleaned up nice with a little final fill.

It bought you a ticket to "The Game" in A2 as long as you act humble after kicking my alma mater's butt. We want Lloyd back. He was your John Cooper.

If I am reading the driveshaft stuff correctly I can get a "hybrid" joint of sorts in the back with a nice driveshaft up front.

Do you agree just have one made versus trying to find one, having it shipped and then going with the u-joint.

 

[Basketcase]

well as far as the Michigan and Ohio State bit...that's the daughter's school, and Plymouth Blue runs deeper than both! My car came from Michigan, and my family vacationed every summer in Frankenmuth. Just glad to help out. The combonation joint is half the larger size for the big blocks, and the other half for small blocks. It worked fine for me, and a buddy has used one for years.

 

[moparchris]

Basketcase.

Did you know that you gave that tire iron to a U of M grad? It cleaned up nice with a little final fill.

It bought you a ticket to "The Game" in A2 as long as you act humble after kicking my alma mater's butt. We want Lloyd back. He was your John Cooper.

If I am reading the driveshaft stuff correctly I can get a "hybrid" joint of sorts in the back with a nice driveshaft up front.

Do you agree just have one made versus trying to find one, having it shipped and then going with the u-joint.

There is a science to driveshafts. If you have one made you should do a little research. Length and diameter can wreak havoc on balacing. I have had problems in the past with cars that have a lot of gear since driveshaft speed is higher in that case. If the diameter is too small it will cause the driveshaft to whip and create a vibration and will kill u-joints. If you are using a stock shaft for a Roadrunner (OEM used) then full steam ahead but if you have one made please do yourself a favor and pick a shaft that will make your life easier. All driveshafts aren't equal, some driveshaft companies skimp on wall thickness and material to save cost. Things to ponder, diameter, length, material, and lastly wall thickness. Here is a link to help you on your way if you need it. The info provided in the technical link at the bottom is priceless!

http://www.markwilliams.com/driveshafts.aspx

 

[george68hemirr]

Basketcase.

Did you know that you gave that tire iron to a U of M grad? It cleaned up nice with a little final fill.

It bought you a ticket to "The Game" in A2 as long as you act humble after kicking my alma mater's butt. We want Lloyd back. He was your John Cooper.

If I am reading the driveshaft stuff correctly I can get a "hybrid" joint of sorts in the back with a nice driveshaft up front.

Do you agree just have one made versus trying to find one, having it shipped and then going with the u-joint.

There is a science to driveshafts. If you have one made you should do a little research. Length and diameter can wreak havoc on balacing. I have had problems in the past with cars that have a lot of gear since driveshaft speed is higher in that case. If the diameter is too small it will cause the driveshaft to whip and create a vibration and will kill u-joints. If you are using a stock shaft for a Roadrunner (OEM used) then full steam ahead but if you have one made please do yourself a favor and pick a shaft that will make your life easier. All driveshafts aren't equal, some driveshaft companies skimp on wall thickness and material to save cost. Things to ponder, diameter, length, material, and lastly wall thickness. Here is a link to help you on your way if you need it. The info provided in the technical link at the bottom is priceless!

http://www.markwilliams.com/driveshafts.aspx

THATS GREAT CHRIS CAUSE I WAS GOING TO TELL HIM ABOUT MARK WILLIAMS....THIS GUY KNOWS HIS STUFF.....SOMETIMES IT MAY SOUND PRICEY BUT ITS WORTH THE MONEY IF YOU LET HIM BUILD YOU A DRIVESHAFT....AND HE BALANCES THEM AT 7500 RPMS NOT LIKE OTHER COMPANYS AT 1200RPMS

 

[meepbeep69]

I have a few weeks.

Any ideas on a used one?

I assume he will make one to fit a small yoke or I can change it.

Below is how it looks in all it's glory.

Body shop friend said it has a quarter longer than the truck beds he's used to.

 

[mcmopar]

I'm on my other computer and ran across this link concerning the 8-3/4" rear end. It includes references to all kinds of stuff, including the 7260/7290 yokes.
http://www.planethoustonamx.com/main/ch ... arends.htm

 

[Roadcuda]

I'm on my other computer and ran across this link concerning the 8-3/4" rear end. It includes references to all kinds of stuff, including the 7260/7290 yokes.
http://www.planethoustonamx.com/main/ch ... arends.htm

Thanks for that one John. It told me something I wasn't sure about. I've seen a few '65 Barracuda's with 8 3/4s in them and this info says that they could be had in them. I didn't think they were available in the '65s. So according to this, I now know different.

 

[Basketcase]

ahhhhhh...nice shiney gren paint