Pinion angle
 

Okay I measured the pinion angle and I am reading 1*lowered tilt at the tail shaft & 4* lift at the rear dif.
See drawing, so if I under stand correctly I need 3* shim under the rear end perches to get me lined up, lowering the 4* to 1* correct?
http://i1326.photobucket.com/albums/...psf669f71f.jpg

Help!
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Re: Pinion angle
 

That is correct. Or drop your trans a bit down to 3-4 degrees.
Your carb might not be sitting level.

Re: Pinion angle
 

How do you drop the trans lower? It is sitting on the crossmember..
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Re: Pinion angle
 

I was always told the pinion should be 4 degrees down so when running forward it torques up and streightens out.

Re: Pinion angle
 

Non-stock crossmember I assume.
What tranny?
What crossmember?

Re: Pinion angle
 

Stock crossmember, 700r4 trans with 72' stock 3.73 gears
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Re: Pinion angle
 

If you can't drop the tranny and your carb is happy then shim the rearend.
BTW I like your 56 belair themed paint job!!

Re: Pinion angle
 

You have seen this thread I hope.
http://67-72chevytrucks.com/vboard/s...d.php?t=569350

Re: Pinion angle
 

Seen it now! Thx
I have it @ 1* equal now!
I' ll run it saterday and see what I hv thx everyone!
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Re: Pinion angle
 

The engine and trans is supposed to be about 4 degrees down to the rear as installed from the factory. This will keep the carb close to level. I'm not sure why yours is only 1 degree.

Re: Pinion angle
 

4 degrees with the frame level?
(what if the truck has some rake to it and you are measuring with it setting on the ground?)

Alot of people talk different degree numbers.
We need to make sure everyone is on the same page

Re: Pinion angle
 

I am not sure why either ( measuring 1") but I am using a digital angle finder so I think it to be correct in its reading ( it's called "smart tool")

I do have the rear on jack stands but I will let her down and read it again

Life got in my way so play time was cut short!
I'll let you know what I find Saturday!
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Re: Pinion angle
 

Okay I brought all my dimension to work with me (even height from ground), and the reason I have 1* and 4* is because:
I have it on jack stands at a 4* slant.
My actual dimensions would be 5* at the trail shaft and 8* at the dif. If it were sitting flat on the ground.
Now my readings are at 5dwn and 5up
Sorry for the confusion; my fat butt can't/didn’t want to creep under there!

NOTE: as long as I am matching angles it really didn’t matter what the angle of the truck was as long as I take both angles while it is up there and adjust accordingly.

But, I do understand now, why you guys are so in-depth! I might have misled some others on here, with the 1* and 4*, without mentioning the jack stands, for that I am sorry! I should have clarified..
FATBOY UNDER TRUCK = LOTS OF GRUTTING & loss of oxygen! ;)
THANKS GUYS

Re: Pinion angle
 

Correct!
I just don't want someone to think that the trans has to be 4 degrees down.
(or whatever number is posted on here)
Just trying to keep everyone on the same page.

Re: Pinion angle
 

Got her out on the hwy, w/ the 3* difference and tah-dah no vibration!
Thanks everyone, now on to the next issue-issues that pop up!
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Re: Pinion angle
 

I agree that the trans output shaft and the pinion should be at parallel angles. However the typical intake manifold carb flange is at ~3* in relation to the crankshaft centerline. It is best to have the carburetor as close to level as possible. Hence my recomendation to start with the engine at 4*. Here is a link to a thread with others with the same thoughts.

http://www.chevytalk.org/fusionbb/sh...post/last/m/1/

Re: Pinion angle
 

Cap, I am thinking that my floor is not 100% level so that would account for the degree differences, (older house on clay soil in OK, this stuff never stops shifting).
If I had a shop with a true floor, it might be dead on, but I must just go with what I have so the matching of the angles is all I can do.
My carb seems to be okay with it's angle (?) whatever it truly is as it will bust off and idle with no problems.

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