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11-24-2020, 06:34 PM | #1 |
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Join Date: Dec 2003
Location: nor cal
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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 nowall 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? |
11-24-2020, 07:34 PM | #2 |
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Join Date: May 2015
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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
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Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver |
11-24-2020, 08:16 PM | #3 |
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Location: nor cal
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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??? |
11-24-2020, 10:08 PM | #4 |
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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
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Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver |
11-24-2020, 10:43 PM | #5 |
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Location: nor cal
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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? |
11-24-2020, 10:50 PM | #6 |
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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..
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Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver |
11-24-2020, 11:09 PM | #7 |
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Location: nor cal
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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. |
11-25-2020, 05:20 PM | #8 |
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Join Date: Jun 2015
Location: Carlos MN
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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.
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