Our 89 25' Regal has a split drive shaft. The front half is about 4" diameter and the rear half is about 3 3/4" diameter. Is that normal to have the two sections two different diameters?

J

This was from my crankshaft job a while back on the 33 Regal:



Close inspection shows the front is slightly larger? Are your shafts the same length? Longer shafts would likely be larger in diameter. I would assume your shafts are OEM. As long as they are balanced I don't think diameter is very important.

Well I assume you will be taking it to the drag strip so the larger diameter is what you want to handle all that additional horsepower!!

Just funning!!!

Did Barth use the same wheelbase for all its P30 coaches?

Many wb on p30's 125,137 159,178 and newer 1988 up with 190, 208 and 228. My 1986 as a modified a 178" that has been extended to 192". you can see the welds on frame and exhaust. Jim and Tera Old Blue had extended to 1925" also.

The 25'er, who I want to call Bert in honor of my dad but have been overruled, has a 158"wheel base. The 28'ers I think 172" was standard. Some 28'ers, notably Old Blue, had a 192" wheelbase.

rear drive shaft shot

knoxville driveline
balance test
rear tubing
2 yokes
2 welds

3 u-joints
carrier bearing
rebalance
$482

This is Tere:
Just took Old Bert out for a test drive after installing the newly balanced drive shafts, new rear tubing, new center wheel bearing & 3 new universal joints. What a difference!! Like night & day.

Yay!!

Looks like you found the problem! Not cheap but considering the number of parts, labor, balancing and the satisfactory result probably not too bad. Good thing you got it before anything let go, they can do a lot of damage if they come loose underway.

Now you're ready for hole shots at the drag strip! In plenty of time to join us in MN or MI this summer.

Have Barth, will travel

Yes,
Well worth what was spent. No regrets! Hoping to travel north this summer.
Tere