Pinion angle

[Gregski]

I am going through something similar with my build and highly recommend this magnetic AccuRemote Digital Electronic Magnetic Angle Gage Level/Protractor/Bevel Gauge

it's really easy to over think this so don't let it

the differential needs to point up at the same angle as the transmission points down, so if the trans angles down 5° try to angle the rear end up 5° or as close to that as you can

then there's the 3° rule which basically means the driveshaft shouldn't angle down from the transmission more than 3° as it slopes down to the rear end

same from the rear end the driveshaft should not slope up more than 3° to run up to the transmission

this gauge makes it easy to measure stuff, you can stick it to the driveshaft right by the rear end and see what it says, then remove the driveshaft from the rear end and measure the angle of where the U joint goes in to the yoke and see what the difference is, again should be 3° or less