Gear Vendor Driveshaft Recomendations

[Guardrail]

Its time to get something done on my Green Machine!

My 69' C20 came as a 350 with TH400 and Dana 60/4.11. Last winter I bolted in a great running 454 out of a donor truck, then installed a Gear Vendor and TH400 adapter I pilfered from a Motor Home. I left the stock trans crossmember in place and will use a new stock type mount. Then I took a break till now.

I think its time to trailer it to the Driveshaft/Muffler Shop to make some new head pipes for the exhaust and shorten the stock 2 piece driveshaft. To me it looks like they might just shorten the front half but is that the way to go? Or do I have them make a 1 piece shaft? Have any of y'all added a GV overdrive on a TH400 longbed and if so, what the best way to go?

[tjc]

I hope you get a good answer, because that is exactly what I am doing this winter.

[kwmech]

How did you bolt in the 454? Using the 350 frame stands?

[biketopia]

I'd imagine you can do a one piece, and just go with whatever the driveline shop recommends really, assuming they are reputable shop and not some fly by night place. Is your truck lowered or do you plan on lowering it?

[Sklptrljay]

I spoke with a well known shop in my area about the same thing on my short bed. You are better off going with a one piece. The hanger for a 2 piece is pretty antiquated in their opinion, and definitely not as good as a one piece in high performance applications. You'll have to verify that a long bed doesn't change that, I'd imagine it wouldn't. You might have to have a bigger diameter driveshaft than a shortbed though.

Good luck.

[wbc409]

I would recommend a 1 piece driveshaft. The biggest issue you will run into is the shaft hitting the cross member that the hanger bearing mounts to. Your clearance should be checked at top and bottom of axle travel. Your clearance will change if you change ride height in either direction. I ran into this problem with a truck I built. It was a 71, 1/2t, 2wd, with a 454 and th700r4. My truck was at stock ride height and my driveshaft length was at the max the shop would build as a 1 peice.
you will probably have to go up to a 3 inch diameter shaft.
The shaft length if I remember correctly was around 68 inches. Your shaft should be quite a bit shorter. I think your combo is at least 10 inches longer than the 700r4.

[wbc409]

Found some old pics. No idea how to attach them to the post.

[leftybass209]

I don't think it's as cut and dry as just using a 1 piece for the sake of it.

Because you have reduced the distance between the diff and the GV output, you may be able to use a 1 piece. Longer shafts require heavier, larger tubing, which also increases rotational mass. You have to take into consideration the way you use your truck because the driveline angles are more drastic as you reduce the driveline length. If you constantly load the bed, never load the bed, tow, or anything that changes the angle of the driveline, it's worth considering the benefits of 2 piece vs 1 piece. Best of luck!

[gvnick]

Nick from Gear Vendors here. Although you could likely get away with a one piece length wise, I dont think there is any chance it would clear the trailing arm crossmember when the trucks rear suspension is completely unloaded. I'd jack the frame up then run a string from the overdrive to the rearend and see what clearance you have.

Shortbeds are no issue with a one piece but of the many longbeds we've done we have always kept the carrier.

[kirklovejoy]

I have a 71 gmc long bed 4 wheel drive with a 208 transfer case behind th400 transmission with gear vendors. No problems with 1 piece driveshaft.
I live above auburn there is a guy who does about 50 driveshafts a day in west Sacramento. Give them a call and a guy will come to your house and take a measurement bring you a new driveshaft the next week.

[Guardrail]

Originally Posted by gvnick

Nick from Gear Vendors here. Although you could likely get away with a one piece length wise, I dont think there is any chance it would clear the trailing arm crossmember when the trucks rear suspension is completely unloaded. I'd jack the frame up then run a string from the overdrive to the rearend and see what clearance you have.

Shortbeds are no issue with a one piece but of the many longbeds we've done we have always kept the carrier.

Nick, so just shortening the front half of the two piece shaft will suffice? On another note I have not compared the yoke that is with the GV to the slip yoke that is on the stock driveshaft. I'd better see what I have.

[Guardrail]

Originally Posted by kwmech

How did you bolt in the 454? Using the 350 frame stands?

No I used BB stands.

[brad_man_72]

I've built dozens of one piece shafts for 67-72 chevy long bed trucks. A short transmission rquires the use of 3.5" diameter tubing. With a large od unit you may be able to get away with a smaller tubing diameter.

There's nothing really wrong w the stock ld carrier bearing setup if the driveshaft is balanced properly as an assembly which some "drive shaft shops" aren't able to do. We have 2 $40k balancers and often balance 5 piece drive shafts for limos.

[LongBox]

Just so you know, the 88-98 GM Longbed pickups use a large diameter, one-piece driveshaft, made of aluminum. My Mustang also uses an aluminum one-piece driveshaft.

Pretty sure the large diameter will not clear the crossmember, but creativity is always available...

[gvnick]

Originally Posted by Guardrail

Nick, so just shortening the front half of the two piece shaft will suffice? On another note I have not compared the yoke that is with the GV to the slip yoke that is on the stock driveshaft. I'd better see what I have.

Yes, you can just shorten the front half and not worry about any angles, the front shaft is very flat. You will use the Gear Vendors yoke, it has the splines slightly undercut to ride on an Oring on the GV output shaft. It will use a 1350 joint and you will need a matching 1350 yoke welded on the shaft if its not the big yoke already.

[Guardrail]

So I went to my local driveshaft/exhaust shop with my C20 on a trailer. He showed me a weld yoke that replaces the front-most yoke on my front driveshaft section. It allows the use of a 1350 Ujoint with my stock sized driveshaft tube. The plan is to shorten the front of the stock 2 piece driveshaft and then balance the entire assembly. My truck is stock height so I do believe this will be the best way to go for me.

[brad_man_72]

Sounds good.