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MG MGB GT V8 Factory Originals Technical - Driveshaft choice

hi,
im at the point where i need driveshaft info, as i need one for the V8 as well as my '75 BMW 2002. the latter i know what to do, but the former is what i need help with. my transmission is a GM T5 and im retaining for the moment, the stock MGB rear axle. will the MGB driveshaft hold up under the increased load, if i get the slip yoke put on the front U joint? or should i go with a modified GM driveshaft, say 2.5"? what has everyone done in this situation? thanks
jake

Depending of course on the motor's spec, it's quite unlikely that the stock driveshaft will hold up. A whole new heavy-duty driveshaft, flange to flance, is not much over $100-$150 so you might just want to have one made up and be done with it.
Ted

Jake, I'd recommend having a shaft made up by a good drive shaft shop. Use something close to the original Chevy or Ford T5 size for the tube and swagged down to the MGB rear yolk size at the rear. No need for a slip joint as the transmission already is built for that. If you're lucky then when you upgrade the rear axle you won't have to have a totally new shaft made, just the rear jolk changed. The B rear axle is a bit on the weak side, but also the 3.9 gears will probably be a bit on the tall side when you get it on the road. You'll probably want to change it as soon as you can.
If you're running wires, this is a bit more of a problem, but I'm working on a solution for my 6 cylinder MGA using a B rear. I'm investigating having the B axle tubes inserted in a GM center housing and having new axles made. This will give me a great gear selection as well as enough strength in the diff.
Bill Young

Jake,

D&D Fabrications has a 2 1/2" diameter driveshaft avaliable for the GM T5 and the stock MG rear. Dan can be reached at 810-798-2491.

Regards,
Joe
Joseph Lagasse

It makes sense to me, that if you where to have a new shaft made up, that was built for the increased power, then it would most likely break at the rear joint if it was to break. I myself (Although I never have had this experience) would rather have it break on the rear, simply because the shaft wouldn't continue to be driven on by the rear axle. How others would feel about this I don't know, but that's one thing I would concern myself with, and seems to me to be a very possible situation because of what we are doing to these cars.

Just my two cents.
Anthony.
Anthony Morgan

Get in touch with Dan at D&D. He was charging about 150 I think. He can tell you the one measurement he needs. He made one up for my V6 conversion that was 1" shorter than the one he keeps in stock for the V8. Also I think he carries the correct speedmeter gears. Don't get rid of your old shaft though as you reuse the flange. Good luck,
John
John

If you have a new driveshaft made to Chevy dimensions, you will have to buy a second driveshaft between 2" & 2 1/2" diameter because that's all you have room for in the tunnel unless you are removing the emergency brake lever. Of course, you could always widen the tunnel....

D & D makes a nice drive shaft, but as most conversions vary, I would suggest you measure the length you need & confirm before ordering. Different motor mount adapters create different engine set backs meaning different drive shaft lengths. Towery sells 2 versions, D & D sells one that is different still.
Jim Stuart

Jim GREAT point.

Unless you are using a kit from one of the plethora of vendors, a "off the shelf" DS is really a shot in the dark.

I have been able to source a specific Spicer unit that allows an uprated rear Ujiont while also maintaining mounting to a stock MGB rear. It has withstood numerous hard shifted runs and not failed. The Ujoint itself is one out of a Ford Ranger V6 pickup, then there is a standard Weld flange for the shaft side and a specific rear flange to mate to the MGB rear end.

The flange to mate to the MGB rear is like $80 list.

But like I said this set-up has withstood numerous hard runs with my 302 running strong.
Larry Embrey

Ted,
Not sure what your "cost of living" is in NH but a base Drive-shaft shortening (if I provide tranny yoke assembly and full tube) is over $225 here in WA.

Man maybe I should move out there!! heh

Larry Embrey

Larry,
Do you have the part numbers for those flanges by any chance, or know what they were originally for? Joe
Joe Ullman

Wow Larry that is expensive. I paid 60cdn to get a Camaro drive shaft cut balanced and 2 new U joints installed. This was for a T5 tranny.


Bruce
Bruce

Larry,
I guess living near high tech. Seattle has some disadvantages :). Here in Spokane I had a new driveshaft made for $145. I took them the MG driveshaft and they gave me one with a new tube, u-joint and yoke and for the T5 tranny end. It was balanced (for as fast as the car would go, I told them 150 MPH). I got the impression prices, quality of the shaft and workmanship (especially balancing) varied quite a bit from shop to shop. Given your knack for finding good pricing I'm surprised you haven't found a better price for the driveline.
Jake, hope this helps.
Rick

This thread was discussed between 04/01/2003 and 08/01/2003

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