pinion angle advise....

ok, i understand how to set my pinion angle and what it needs to be in relation to the angle of the output shaft on the ******.

i'm getting ready to set-up and weld perches on the nova rear i have for my '53 chevy.

my questions is, i'm planning on running 2" or 3" blocks.
should i set up my pinion angle with the blocks included in it?

or just set it to it's corisponding angle with the ****** (w/out blocks) and adjust with shims after blocks are in?

i ask because i have 2" blocks for the rear right now...and i'm thinking of changing to 3" blocks, which i don't have at the moment.

should i wait 'till i've chosen my block size THEN set the pinion angle to weld the perches....?

thanks.

Chris

 

the blocks should be parallel (top and bottom) so the angle will be the same with or without blocks.

 

cool. thats kinda what i was leaning towards....just wanted to make sure.

thanks

Chris

 

Go ahead and pick what height your car will be running. Use the front face of the pinion yoke, where the straps seat up, as your reference point. Do not use the casting of the axle housing as any kind of reference----unless you're pulling the rear cover off and using that machined surface. Have the rear suspension at normal ride height, NOT unloaded.
Stay within 1 degree of engine/transmission angle--measured on the oil pan rail or timing cover face. Always use a machined face known to be parallel or perpendicular to the crank centerline or pinion centerline.
If you run into floorboard clearance, you can run what some engineers call "broken back". That places the pinion centerline lower in the front, instead of higher. You will need a dummy or good driveshaft. The goal is to have the exact same u-joint operating angle at each end, no more than 1 degree difference at each end again.
Good luck, double check before permanent welding.

 

cwwatson, On thing to keep in mine when running blocks is that the rear end will have more leverage to "wrap" up the leaf spring, so when running blocks I've always tuned in about 1/2 a degree nose down for every inch of block, that way when you step on the fun pedal and the drive shaft is under max load (when the universals would be seeing the max stress) your pinion angle is where is should be, rather that nose up a degree or two. quite a few companies make shims for setting pinion angle, mostly circle track and off road companies. I have always just chucked mine up in the mill and skimmed off what I needed.