Shackle Flip & 52" springs, what will happen?

[hawkeye649]

Currently my truck has stock springs, and a 3" body lift. 1990 GMC Jimmy, 350/700/241/3.73's 1/2 ton.
I have an ORD shackle flip kit for the rear. If I gather my information correctly, I shouldn't need new drive shafts? At least for the time being, IE they will physically work. Also has anyone had any vibration problems after this, as this obviously changes the pinion angle in relationship to the t-case angle. And if I'm not mistaken, for a smooth ride those angles (ie u-joint angles) are supposed to be the same within about 1 degree.

I wanted to do a 52" spring swap up front. Looks like a bad ass way to do things, more flex, more lift, and on the cheap. If it moves the front axle forward, should I have any problem with my 35's contacting the rear of my front fender?

As you can see the axle doesn't look very centered any more after trimming the fang on my truck.

Here is a picture of full stuff.

If I were to turn my wheel to the left, it would basically touch the inner fender and try to push the outer one off the truck. And this pic is of a worn MTR, so a new one would be contacting the inner right now.

So between being moved I think "they" say like 2 inches forward (which would solve this problem as I see it right now, so even zero rates could do this) and the extra 4" up, I shouldn't have any fender contact? I just don't know how far back the 52" setup shifts when under full stuff. I'd also have to assume it actually doesn't stuff up into the fender as far as the stock ones do, since the 52's should never be pushed into a reverse arch like the fronts are stock?

 

[hawkeye649]

Ttt??

 

[MTMike]

With stock 52's, 3" body lift and 38.5's I had to trim moderately. I would have had to trim much more if the 52's didn't move the axle forward 2-3"

You will most likely need a new driveshaft. It will need to be ~3" longer at static height, and capable of not coming apart or binding when flexed. I dropped a huge chunk of change on a custom High Angle Driveline so I'd never have to worry about it again. It's got ~14" of slip and a 42 degree CV.

Using a stock driveshaft with a 52 conversion would most certainly have problems. You'll also need to address shocks/shock mounts, brake lines, etc.

Mike

 

[hawkeye649]

With stock 52's, 3" body lift and 38.5's I had to trim moderately. I would have had to trim much more if the 52's didn't move the axle forward 2-3"

You will most likely need a new driveshaft. It will need to be ~3" longer at static height, and capable of not coming apart or binding when flexed. I dropped a huge chunk of change on a custom High Angle Driveline so I'd never have to worry about it again. It's got ~14" of slip and a 42 degree CV.

Using a stock driveshaft with a 52 conversion would most certainly have problems. You'll also need to address shocks/shock mounts, brake lines, etc.

Mike

So I'll probably be driving a 2wd truck for a little while after the swap. Guess it's time to buy some stoopid duty shock towers and some nice shocks for the beast too. It's just that the lift needs to be done and in, in 1 weekend because this is my only running truck. So for-seeing problems like a vibration to end all vibrations would be nice.

 

[smokkey1]

if you go with the 52" swap your going to need crossover.

 

[MTMike]

if you go with the 52" swap your going to need crossover.

Almost forgot about steering - yes, 52's require x-over steering as well.

 

[hawkeye649]

Almost forgot about steering - yes, 52's require x-over steering as well.

That is most definitly something I had not gleaned from my readings. Hmm... Now I wonder if D44 knuckles will go on a 10B, because I have a flat top D44 6 lug under my 75 blazer.

 

[dremu]

That is most definitly something I had not gleaned from my readings. Hmm... Now I wonder if D44 knuckles will go on a 10B, because I have a flat top D44 6 lug under my 75 blazer.

Yep, they do. As a matter of fact, you HAVE to use D44 knuckles for the 10b crossover, as 10b's never came in a flat top.

D44's and 10B's are the same from the knuckles out, anyway, so they swap parts nicely.

I was fortunate that I had a flat-top D44 under my '74 when I bought it, and when I went 8-lug, I just dropped in a matching 14bff and 10b... voila, leaving the flat-tops read to be stolen for crossover

-- A

 

[muddermilitia]

When you install the shackle flip, you will definitly need a new rear driveshaft. One with a double cv at the transfer case end. The shackle flip will give you very good pinion angle, but the angle at the transfer case is not good. If you drive it with the stock driveshaft it will vibrate pretty bad. I ordered a double cv driveshaft from driveshaftsuperstore.com a week before the rear U-joint blew on my blazer. So I was without a truck for only a little bit.

 

[DougK20]

I wanted to do a 52" spring swap up front. Looks like a bad ass way to do things, more flex, more lift, and on the cheap.

Ha, ha. A cheap 52" conversion is the biggest misconception out there. You are talking thousands to do it right.

 

[cybrfire]

4" shackle flip in the rear and B52's in the front.

Not sure on the RTI score and ramping is not real world testing. That being said I'm using the Ford shock towers. X over and high steer. Haven't had a drivline vibration at all. Don't have a double cardan joint on the rear shaft either. Not sure what the front shaft came from but it was approx. 1" longer than the one I pulled off of it but for sure a factory shaft.

Just my experiences with this setup.

 

[hawkeye649]

Nice, thanks for the pic and the description. Were you the one who was working on the narrowed green blazer? I think you were, I want to say it was a 502 caddy, narrowed front and you bobbed your hard top to make it like a truck. Got any pics?

 

[cybrfire]

Nothing recent. Maybe I'll snap a few this weekend at the open house. Plan on having it outside in the sunlight for a change. Hasn't really changed much in quite a while. Got side tracked on the tow rig and then got side tracked on the shop and R and D rig and its hard to find time to do anything on any of them, but that is a good thing.