Pinion angle, modded '68 Mustang
The 393 stroker and T5 in my '68 Mustang are angled down (towards the rear) at 5°. This is as high as I can get the tailshaft under the trans tunnel due to the slightly increased height of the T5.
The Currie 9" rear, a new custom rearend, sits on stock Eaton GT springs with no blocks or modifications. The pinion points downwards at -2° towards the front. This is clearly not great, so I tried some wedges under the spring perches to help. I got the pinion up to +4° with some 6° wedges, but they raised the rear too much and it fouled the wheelarches and exhaust on full travel.
So I have a pair of new perches from Currie, and am about to cut off the old ones (one at a time, after some very careful measurements) and weld the new ones on to give me a pinion angle of +4.5°, giving a little allowance for torque reaction.
This mod will leave the driveshaft at nearly horizontal, maybe going a little negative when the car is loaded. Anybody see any problems with this - I'd be very grateful for thoughts?
Car is for street use only, no drag racing.