Pinion angle help
 

Hello I have a 71 nova ,sbc 625 hp, I've changed over everything in the drivetrain, Trans=PG, Drive line= 3.5"DOM W/1350 joints, Chris alstons 9", Cal Tracs split leafs and Cal Trac bars, 10.5" MT slicks. to set up the pinion angle I measured the crank shaft/trans center line angle and the pinion angle with the driver in the car and the weight of the car on the tires. I found them to be within 1/2 degree of parrallel of each other ( the half degree was negative or down at the pinion ) the drive line working angle is 5 degrees. I've installed 4 degree pinion wedges to get more negative pinion angle which puts the pinion angle at about 4 1/2 degrees negative. With the drive line working angle at 5 degrees and the pinion angle at 4 1/2 degrees negative with respect to the trans center line angle it put the rear u joint angle total at 9 1/2 degrees static. Does this sound correct?

pinion angle
 

A FRIEND OF MINE HAS A 69 CAMARO AND CALTRACS AS WELL, WE TOOK HIS CAR AND USED THE GROUNG AS LEVEL OR ZERO DEGREES AND THEN WENT AND PUT 2 1/2 DEGREES PINION ANGLE IN IT AND IT LEAVES VERY WELL, ALTHOUGH ITS NOT A FAST CAR (11.80S). HE HAS 515 HP AND THE CAR LEAVES GOOD WITH ONE TIRE IN THE AIR ABOUT 3 INCHES...YOU HAVE A LITTLE MORE POWER, IF YOUR NOT ROLLING THE SPRINGS OVER AND BINDING THE REAR UP, I WOULD THINK 2 TO 3 DEGREES IS PLENTY...HOW FAST IS THE CAR?

Is this a race car or street car. You also have more degrees then you need already.
The more degrees the more power loss you have

It is a race car . It has 4.5 * pinion angle now. I'm thinking about taking 2* out to be at 2.5* but I dont know how much spring wrap up to expect from the Caltracs split mono springs.

cal trac set up
 

i used the same set up for years in a 79 camaro set the pinion angle at -2 put a dime where the alaumium piece sandwichs the leaf on top remove the dime and it sould work good i would go mid 1.30s in the 60 with that set up

pinion angle
 

the relationship between the driveshaft and rear and the driveshaft and the tranny are not as important as the angle of the rear to the ground. with a leafspring car more pinion angle is disired.BUT with the caltracs it will iliminate the wrap up of the leaf spring helping you pick up the front of the car quicker.that being said I would still set the pinion 2 degrees down in relation to the ground, on a level surface,say the pits at the track. the rear end is probably offset to the right 3/4 or 1 inch. so that puts a couple of degrees perpendicular to the rear, also not a concern, and the tranny is possibly mounted in the original location making the front yoke angle what it is. over all it sounds like it's abit to much angle if it's 4.5 degree down. thx Pro Mod Chasis tuner