What is the difference between a tapered lift bblock and a regular lift block? And are there pros and cons of each?

Thanks, DB

 

You use either one depending on the body style of your truck. I believe the shorter wheel base trucks (regular cab/long box and super cab/long box) use the tapered blocks while all others use the flat ones.

 

So it has nothing to do with how the blocks make the truck sit or ride? Just depends on which block fits ur model of truck

 

No it has nothing to do with that and ride height is determined by wether they were from an F250 or F350. F250 is 1 7/8" tall and F350 is 3 7/8" tall.

 

Well im looking at aftermarket blocks. Im getting a 6" lift so i will need 4" blocks, and i notice some say tapered and some say flat, so Ill have to make sure i get the right ones.

 

One piece driveshafts.....tapered block
Two piece driveshaft......flat block and a carrier bearing shim.


Only difference is that the tapered ones change the pinion angle and the flat ones do not.

Note* some custom two piece driveshafts that use a CV after the carrier bearing need a tapered block as well.

 

I used a tapered block and have some driveline shudder. I've read this is because the pinion angle is different from the transfer case output shaft. Using a flat block keeps them parallel and is the best configuration, is this correct?

 

Does your truck have a one piece rear driveshaft or a two piece rear driveshaft with a carrier bearing?

If it's a SC SWB, I think it has a one piece....SC LWB has a two piece.

 

Its the one in my sig, super cab, short box. It has a one piece driveshaft. Overkill suggested I replace my tranny mount with a 7.3 one since it has some play in it and he says the 7.3 tranny mount has better isolation.

 

Yep, if the angles are good on your driveshaft the 7.3 trans mount is much stiffer vs. the 6.0 one.

 

So should I switch from tapered blocks to flat blocks to get my pinion parallel with my transfer case shaft before I change tranny mounts? If the different tranny mount will just hide the problem I'd rather fix the source.

 

Is there a CV on the driveshaft by the t-case?

 

No there is not, if there were the pinion should be angled towards it, correct? Sorry I kinda hijacked this thread...

 

You are right on track, Cartmanea. If you have u-joints on both ends of the driveshaft, the total angle needs to be divided equally between the u-joints on each end of the shaft. If you have a CV on one end and a u-joint on the other, you want to try to minimize the angle in the u-joint (e.g. pointing the pinion up).

As the angle increases on a u-joint, it imparts a variation in the rotational speed of the shaft, twice in each revolution. A properly-phased u-joint on the other end, with the same angle, cancels this variation back out. So having the pinion and the TC output shafts parallel is ideal.