One piece driveshaft?
 

would i need to go to a one piece drive shaft if i lower my gmc 4/6? its a 1/2 ton, with leaf springs in the rear (gonna re-arch them and put a 1 1/2" shackle....let me know what u guys have to say, cause my dad wont let me order the kit until i know it will work out perfectly. and also if there is anyone who has already lowered their truck 4/6 by themselves, please..let me know how it went, i want mine to go as smooth as possible.
thanks,
Kevin

I've lowered mine 4.5/6 with ECE's kit, only my truck has coils in the rear. I have lowered trucks with leaf springs in the back and as long as you take your time it shouldn't be anything you can't handle, just keep safety first and remember that springs have pent up energy that can be dangerous.

I haven't ever owned a truck of this body style with leafs in the rear, but if you're looking for a 6" drop, I THINK that a flip kit will get you there and keep your load capacity the same. Maybe someone else will chime in on this and confirm.

Lastly, with the 6" rear drop on my truck I didn't HAVE to go to a one-piece due to lowering. I put the one-piece because I wanted to get rid of the vibration that mine had in it due to the carrier bearing, plus it's a weak point in your driveshaft if you're going for big power.

Good luck

did the vibration in the carrier bearing come after the lowering of the truck? or was always a constant problem. thats what my dad wants to know, caus ehe doesnt want to have to help me replace the carrier bearing every weekend. whats it take to put the one piece drive shaft in it? and where did u get it?
thanks for u help

Kevin

The vibration was there before the lowering. On a leaf spring truck, the axle should only go up and down as you lower it, the coil spring trucks tend to push the axle forward as you go lower which could be a problem for the carrier bearing if your driveshaft doesn't have the slip yoke on the rear portion.

To put a one-piece driveshaft you have to drill out the rivets the hold the carrier bearing bracket to the center crossmember (see pics below, both are from front of x-member), other than that it;s a simple remove and replace deal. I ordered my driveshaft from Denny's Driveshafts , it wasn't cheap but I'm going for a powerful engine & I didn't want to take any chances. If you're looking for a less expensive route, you could measure straight-line from the U-joint on the Yoke of your rearend to the U-joint on your tranny yoke and take that measurement to the junkyard and look for a suitable replacement.

you can put power through a multiple piece shaft...had a bud running 12's on his street driven 67 LWB...never had a problem.

so a 4/6 drop with leaf springs in the rear doesnt require a single piece drive shaft? dang...12's?.....what did he have in that thing. then again i did see a 68' chevy running 11.33 at Infineon Drag strip

350/th400
a huge cam, some seriouse porting on 882 heads, about 9 1/2 to 1 compresson, 3000 stall, 4.10 gears....one slick on the right rear.
Don't know what carb it was, but the intake was darn near a tunnel ram intake.

sounds sweet....makes my motor sound so stock...lol

the block is Chevy orange, Edelbrock preformer intake manifold,Edelbrock 1406 carb, chrome valve covers and chrome air cleaner, a cam outta a 327 corvette motor (has a nice noticable lump to it...) and some long tube Headman headers (black)

What i really want is either a new corvette motor, or.... a crate 572c.i. BBC with a 14-71 Weiland Blower. that would be sweet.

I went 10.98 with a 2 piece driveshaft....I only did this once though...went with a one piece this year

Tell more jim, your down in the 10's now. You gonna make the 9? Thats a BIG difference though. Good luck

I think that will be my only pass into the 10s for a while(did it just to do it)Not going to be running N20 this year...well maybe ...lol. I should be running 11.50s on engine alone once I get it tuned..same engine just advanced the cam...took 150lbs off the nose and added a trans brake with a th400..oh yea..some big ol headers