HQ 1 Tonner Tailshaft

[christophe]

I have a HQ 1 Tonner . took 253 and m21 box out . now puting in 350 chev . with turbo 400 in . do i use same tailshaft. i no i have to change the end pice that goes into box.but do i have to get the tailshaft cut down ? or keep it the same length ? thanx chris

[Godzilla]

The best person for this would be a member called "Intelligeorge", if you send him a pm im pretty sure he could answer it, hes pretty cluey with GM's.

I think the simplest way to answer your question is to ask if the rear transmission oil seal will sit at the same point with the new set up. If it does it will point towards the same length tailshaft, but have you checked if the m21 yoke will fit into the turbo400 (i dont think so) and if a turbo 400 yoke could be fitted to the standard tail shaft (are the universal joints the same size).

Now the hard part...how i use to calculate tailshaft lengths.

Stock diff; Take the springs off or load it with sand bags till the diff is on its bump stops while the car is on diff axle stands so you can get under it.
Measure the diff flange (if flat) or the center of the uni joint (if curved diff flange with u bolts) to the transmission oil seal.
Place the turbo400 yoke into the tranny all the way in and pull it out by about 3-4mm for non leaf spring setups or 6-8mm for leaf springs and mark where the oil seal sits with a marker.
You now know the length of your tail shaft from the flange or center of the universal joint (depending on the diff flange you have) to the marking pen mark on the yoke that goes into the tranny.

Now jack your car up till the diff is hanging off its shockers and remeasure.
Make sure the extra length leaves enough yoke in the tranny so the tailshaft cant fall out if you get airborne.

If setting up a aftermarket diff yourself make sure you setup the geometry correctly.
The diff pinion should be pointing at the tranny output when the car is sitting on the ground with a driver and fuel in the tank if its non leaf spring.
Leaf spring setups require the diff pinion to look a little lower to allow for leaf spring windup on hard launches, and a little less if your running tramp bars.

Check a mid 70's statesmans drive shaft, i think a mate had on with a 350chev and turbo 400, im not sure if they used the same wheel bases though.

[Redwight]

If it doesn't fit get spicer to make a new one, cutting them down only works if you know a talented machinist. I've been down that path.

[Godzilla]

Dont even think about cutting it down yourself, ever see how they balance one?LOL

Yep plenty of places can do it for you, maybe get a HD one made up to take the strain.

Ever seen one break at the front joint? Not funny.

Infact if your developing some serious HP get a loop made up, it might just save your life.

Whatever you do, cutting and shortening a tailshaft is not a backyarder job.

Changing yokes and universal joints yes.

[Min]

I agree with Godzilla, dont even attempt to cut 1 down yourself. Also take the advice about getting a loop made.
I got a HQ shaft many years ago and took it to a repco machine shop and they cut it down to suit a LJ torana. I dont remember how much it costed but it wasn`t much. I`m sure you`ll find a place near you that`ll do the job for ya. For me it was simple, I just had to provide the stock shaft and the HQ shaft.

Once again, Godzilla has pointed a good way to measure the length.

[christophe]

Thanks for the info fellas. Ive had tailshafts cut before. for vk and brock commodore.Ive got to tailshafts with th 400 yoke. 1 was in my HQ sedan and the other was in my station wagon both diffrent lenghts. witch both had 350 with turbo 400. what im going to try first is swap the 400 yoke . and put it in the standed 1 ton tailshaft and see what happens . Ill keep you informed

[watchdog]

I've got a mate doing a one tonner at the moment & he was telling me that the one tonner wheelbase is about 6" longer than the sedans , waggons etc. So I'm thinking you may have to lengthen the tailshaft. This is on a HQ so I don't know if other models are different

[intelliGEORGE]

The HQ utes were built on the longer, 114", wagon and Statesman wheelbase, as the Statesman came out with the 350ci you'll be better off sourcing an old statesman tailshaft. Technically should bolt in.

[Godzilla]

Hey George good to see your still around.

We have been missing a GM specialist around here mate.

[intelliGEORGE]

Hey George good to see your still around.

We have been missing a GM specialist around here mate.

LOL, I am working in WA atm so internet is a little dodgy. Just popping my head in to see what's going on. Hope your xmas and new years went well.

[hoe]

LOL, I am working in WA atm so internet is a little dodgy. Just popping my head in to see what's going on. Hope your xmas and new years went well.

you're not in kalgoorlie stealing kalboy's work are you ?

[Godzilla]

LOL, I am working in WA atm so internet is a little dodgy. Just popping my head in to see what's going on. Hope your xmas and new years went well.

All good, hope yours went well too.

Married/kids yet mate? (im guessing your busting your balls to pay for the wedding or bills)

Started to wonder what happened to you, its good to see you around again.