Extreme toploader help--Dhearne et el

[dennis112]

Over the winter I want to update my SBF toploader to big block specs. I am going to use the 1 3/8" wide ratio "long" input shaft, the appropriate bearing and the throwout bearing snout. I pretty much have the front covered and I am fairly knowledgeable about the toploader workings. I am also familiar with David Kee's wonderful toploader website.

My question concerns the tailshaft housing needed to install the new 31 spline output shaft. I currently have the C4ZR Mustang tailshaft housing that was used in most 64-73 SBF Mustangs--Rear shifter and 14" long. Do I need to purchase a different tailshaft housing in order to swap to the 31 spline shaft??? Is this as simple as a bushing swap or will I be buying another housing? Can I machine my housing so that the bushing and seal will fit?

 

[D.Hearne]

Pretty sure the tailshaft housing's are different to accomodate the bigger output shaft diameter. Never had one of these creatures in hand. Closest thing was the 390 transmissions. Give David Kee a call he'll know. The big block tailhousing mounts the shifter about 4" farther forward than the SBF Mustang tail. David's got new tails with both bolt patterns drilled and tapped. Sort of a universal tailhousing. I ran the small block transmissions behind my 427 and never had trouble, but then I never subjected it to hard dry burnouts with sticky tires either.The guy I sold the car to did blow the trans and a 9" rear with a button clutch and M/T 50 series tires at the drag strip.

 

[DK832]

Might want to call Toploader Heaven too. VERY helpful and VERY knowledgeable. Has some great descriptions with pictures on 'how-to'.

 

[dennis112]

HP +stick shift + drag slicks = an expensive pile of scrap

OK, thanks guys. I too have had and built ots of toploaders, but all of them were SBF or 390 based. I do believe that it probably takes a different tail housing, but was confused in that the forward shifted BB housings that were mentioned used the same casing #'s for both 28 and 31 splines.

I've reached the point with my car where it is time to upgrade the both the SB tranny and the rear. In the last 2 weekends at the track I've done this to my toploader:

And this to my 31 spline 9" rear:

Luckily I had another input shaft on hand and that was a quick cheap (and probably temporary) repair.

I since replaced the axles and the True Trac with 33 spline Moser stuff--including a spool so I should have that beefed up enough for the time being. I also got the new axles lengthened so that they take advantage of using more of the splines.