View Single Post
Old 06-30-2012, 06:45 PM   #270
OKGMC4
Registered User
 
OKGMC4's Avatar
 
Join Date: Oct 2009
Location: Broken Arrow, OK
Posts: 1,216
Re: Yet another GMC build

To anyone considering a C4 swap in a 55-59....

1.The back was too high. To get the back to sit right I've lowered mine 2.5 inches from stock. That was 1 inch from shaving the sides of the rear spring and 1.5 inches from longer leaf spring bolts.

2.The front was too low. I kept bottoming out on dips in the road. Some suggested the cradle was installed wrong but it was the original corvette K member brace up front that was hitting. I think it was a combination of the engine sitting farther forward than a vette and a body that is heavier than a vette placing too much weight on the fiberglass spring. I talked to Paul at Newman Car Creations and he helped me achieve a solution. The spring can be shimmed both at the tip and in the center to achieve more ride height. You can use up to 1/2" at the tip and 1/2" in the middle and what you shim gives you double at the fender lip. I put the maximun amount in mine and got the full extra inch I was looking for. It still sits low but more manageable. Now I don't scrape my driveway with the bumper coming out. If he ever reads this...Thanks for the advice Paul!

3. Shocks...still fighting this. I bought this suspension for another car originally. I also bought a brand new set of Monroe Sensatracs. 6 years ago. Now, at 150 miles on the road they are blown. One bottomed out in the rear so bad it got stuck and made the truck sit crooked. Maybe they are old, but what if they had sit in the warehouse that long? In any case they push in with no effort and are junk. On the Vette message boards they all say NO to Monroe, and KYB are 50/50. The only shocks they all agree on are the Bilstein. Soo..I've got the rears on and still waiting on the fronts in the mail. The rears are almost impossible to push down on so I hope this takes care of my suspension problems when the front go in. Especially at double the cost for four shocks.
__________________
56 GMC BUILD THREAD:
http://67-72chevytrucks.com/vboard/s...d.php?t=368649

69/67 chevy/gmc LS powered unibody:
http://67-72chevytrucks.com/vboard/s...d.php?t=624747

One piece window conversion Blackdiesel style:
http://67-72chevytrucks.com/vboard/s...d.php?t=366078
OKGMC4 is offline   Reply With Quote