Pinion Angles after TKO 600 swap
 

After searching threads about correct pinion angles I am wondering about the working angles on my DS. Im running a SBC on a lowered short bed with a one piece driveshaft. I ordered a TKO 600 "KIT" that included a cross member. When I installed the motor/trans the angle was obviously wrong. Way too low in the rear. Called them and they said it must be my motor mounts. All new parts so I figured I would call other places that sell these sort of kits. Long story short American Powertrain was nice enough to tell me there cross member specs. I modified the crossmember to match. So here is were I am now:(all measurements done at ride hight)

Engine/trans 5deg down at rear (trans is almost against floor w/low hump)
DS 1deg down at front
Rear 5deg up in front (using 2deg shims)

Using the Spicer calculator I get Operating angles of 4 in front and 6 in rear

Are these too high?

Re: Pinion Angles after TKO 600 swap
 

Personally I wouldn't want my angles at 5 deg..I always shoot for 3deg..
Could you change to a high hump to fix the angles..?
Ideally you want between 2-4..
My 2cents
This write up by silversport is pretty good..
https://shiftsst.com/blog/post/driveline-angles.html

Re: Pinion Angles after TKO 600 swap
 

Great info... a bit sobering since my new motor will wind to 6500.

To my thinking (or lack of), the initial engine angle is a combo of the angle within the frame as well as the rake of the truck. I was thinking that I could adjust the other angles after the engine/trans gave me a baseline.

That said I'm pretty sure I can get another 1deg with a crossmember shim. If I do this in combination with removing the shims at the rear, I can get 4deg - 0deg(DS) - 3deg.

Working angles are then 4 and 3... The SST site sounded like the rear working angle is the one to worry about???

Re: Pinion Angles after TKO 600 swap
 

The driveline angle diesnt have much to do in relation to your rake... it's the angle of the engine/trans in relation to the rear diff that matters..you could jack the rear end up a ft higher..but it's still the driveline that matters

Re: Pinion Angles after TKO 600 swap
 

Yes... that's what I was trying to say about rake. Realizing that its all about the "working" angles not the XXXdeg of the trans. Still it's quite frustrating when you pay $$$ for a kit that you think had the basic geometry figured out.

Anyway, moving forward, the question is... if I get the 4deg out of the engine/trans, will I have what I need?

Or should I go for the extra 1deg and do some floor surgery?

Re: Pinion Angles after TKO 600 swap
 

It takes a good bit of movement to get 1 deg...
Like i was saying...I've set up all mine at 3 deg down and up...then work around that...if your tunnel is easy to remove you might try jacking the trans to 3 deg and see what would have to be done...
If it was close 4 would probably work...I've seen much worse..my IH was like 9 deg from the factory..but those trucks were low rpm low hp and only ran about 50mph... I changed it all to 3 deg when I rebuilt it..

Re: Pinion Angles after TKO 600 swap
 

Yeah, good point on the actual rise to get that 1 degree.

Thanks for all the input. Even if the numbers don't give me the answer I hoped for, at least I now understand the situation much better.

Re: Pinion Angles after TKO 600 swap
 

When I had a T56 in my 68 I set the angle at 3.5 degrees and it was fine. Also look clearance where the drive shaft goes thru the trailing arm cross member. It was really tight and I had to trim it a bit.