Ion

Hi, does anyone know the length of the tail shaft for a 1966 442 Convertible with short tail TH400? Could be interrested in buying if someone has one.
I also read that I have to weld on some longer tabs for the crossmember, thats no biggie?

Going to swap the 330 for a rebuilt 425 this winter, and I guess the ST300 would scream in pain if I where to keep it, so with the 425 I also got this belonging TH400.

allyolds68

When I installed my drive train I knew I probably didn't have the correct length driveshaft. I used this to measure:

https://www.dennysdriveshaft.com/how_to_measure.html

Then I took the driveshaft to my local fleetpride.com and had them shorten it. It was about $100 to have it shortened and balanced

rocketscientis

Just did shaft roundup for that exact same situation..measured my 442 to b certain....use th short yoke & make certain yoke can travel into tailshaft 5/8 or so as diff travels in an arch & tranny dont..of th. 80 or so shafts correlled at th round up 10 -15% were 60" & some had th 400 yoke..only 1 was 59 1/2
if u make one use a respectible dia for dependability....one shaft not so big twisted like a pretzel in middle...to yield...front of rear 1/2 dug into track..upliftin & side shiften *** end while granadeing rear joint & came straight up through floor & rear seat bout 10"... at 100 + mph.,...& its true theres fabrication in relocatin x member mnts..moderate skil level...dont by chance hav fan shroud or pieces of one??...... Outa 50 or so diffrent ones. I hav 5 or so that are real close but not anything th average owner could bolt on ..any 66 olds shroud except toro would do if so pls call / txt 9897219432... Thanks

joe_padavano

A few things to consider. First, driveshaft length depends on rear axle in addition to trans length. The various GM axles to not have the same dimension from axle centerline to pinion yoke. There can be up to an inch difference.

Second, a 1966 A-body will not have the provisions for mounting a trans crossmember in the TH400 location. On a hardtop with the open channel frame, you can simply slide the crossmember rearward and drill new holes. On a 64-67 convertible with a boxed frame, there are tabs welded to the box section to support the crossmember. The 64-66 cars do not have tabs long enough to support the crossmember in the TH400 position, since it was never an option in those years. The 1967 cars have an extension welded to the tabs to accommodate the TH400. You will need to fabricate and weld similar extensions onto your 1966 frame.

Third, since the e-brake cable hangs from the trans crossmember, you will need the front and intermediate e-brake cables from a 1967 442 with the TH400. These are available new from RockAuto. The rear cables that to to the backing plates do not need to change.