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Discussion Starter #1
I'm probably over thinking this but the more and more I read I start to 2nd guess myself. I'm building a 66 nova with tci pro touring front and rear torque arm with a turbo LS installed. I have never messed with driveshafts or rwd installs such as pinion angle and engine angle. Everything I'm reading is the magic 3 degrees that the engine should be at. Now is this 3 degrees with the tail shaft above or below the front of the engine?

Then I read that 3 degrees may be for carburetor engines and you dont need that much and 1 or 2 degrees would be for maximum horsepower transfer to the rear wheels.

I will add that this is a street car with weekend fun in mind. I don't need a ultimate setup for drag only but it will see some track time if that matters

I want to get my driveshaft ordered because it will be weeks out, but I'm just concerned on measuring the length if I need to change the engine angle. I do have the car at ride height and stance I want. I understand how to measure for the driveshaft, but how much will changing these angles affect the slip yoke clearances. What should I put the rear pinion angle at to measure for the drive shaft?

Which leads me to my 2nd question. After all of that I will need to set my pinion angle. What will I want to set it at after I get the driveshaft installed. Any help is appreciated.
 

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The shortest distance between two points is a straight line.... so without any angles, that should be the shortest length, for a drive shaft, angles introduced by angling the engine or the pinion will not make much difference...Just make your measurements and tell you driveshaft builder that everything was lined up straight, no angles. They will know how to build it. You should go to the TREMEC website and download their APP for setting driveline angles. This way you can use your phone to measure the angles you have and know if they are within spec.
 

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The general rule is that you want equal and opposite angles. This means that if you have your motor/transmission angled down at 3 degrees, you want the pinion angled up at 3 degrees. If your motor/transmission is at 2 degrees, the pinion needs to be at 2 degrees. I set mine at 3 degrees and it runs smooth as silk.
 

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I agree with Chevy II Guy... but you also need to take your driveshaft angle into consideration when figuring out the optimal driveline angles.
Your driveshaft needs to be about 1°-2° different than the engine and pinion angles to eliminate vibration and premature U-joint failure.

Below is a link to a discussion about driveline angles that may also be helpful.
 

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I agree with both Chevy II Guy and RifRaf. They are spot on. I could not have said it better myself.
 

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Discussion Starter #7
Thank you guys. This was what my first thoughts were but the more I read, the more i got confused. Did some measuring for the driveshaft work sheet and its making more sense. Thanks agian.
 

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New here first post the 3 degrees up in front or as they are saying 3 degrees down at the back helps also with stopping air pockets in cooling system filling and purging air. The carb base is also leaned forward to compensate.
 

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If you are dealing with a stock body car, you need to install the engine and transmission that the same angle as the factory did to get it to clear the tunnel. That's 4° on a Nova.

Unless you're building something out of the ordinary, you'll have a small angle of the driveshaft to the transmission and pinion. Avoiding a "zero angle" is overplayed. Just driving the car, even granny style gives you enough movement to never really have it.
 

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I don’t think there’s any engine company that doesn’t have failures. And the ones that say they don’t are liars. So take all the bashing with a grain of salt. When I was at the machine shop we did our best building engines. But we had one blow up on the dyno and another had oil pressure issues when it was put in the car. We tried to get that one back but the owner went to the track and blew it up.
 

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I too have a '66 and had some bad vibrations after my TCI clip with small block and T56 installation. My Nova was a drag car and the diff was welded to the spring perches with the pinion low for drag racing preload. My engine angle was too great so I changed the cross member mounting scheme to make it close to stock. One surprise I got was that the TCI clip moved the engine centerline back to actual center and that the factory set the engine/trans 1" towards the passenger side. Setting the engine/trans angle and pinion are critical for long u joint life and no vibrations. I bought an angle finder and use the App from Tremec for my phone to measure them. Be sure to remove any cover from your cell phone that may change the readings.
Check out the excellent set up article by Hot Rod Magazine."How to set pinion angles".you will find it most helpful with a search online for it. Good luck.
 

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Discussion Starter #14
Thanks for all the replys. I downloaded that tremec app and was playing around with it. That is a nice little basic app. I talked to some people at my work and found out my coworker brothers both work at a local driveshaft company. He was very helpful just like you guys were and from all your responses and his, we are all on the same page. He even has a excel spread sheet that made sure the metal he choose for my application was strong enough. "True calculation would have your torque calculated at your take off rpm then multiple by transmission ratio for first gear, and what diff ratio. Then tire size and width of tire. Open or locked and loaded weight on rear axle during excelleration." He says that this driveshaft has a strength safety factor of 2x before failure. Only takes a couple days to get the driveshaft made rather than weeks and saved me some money.
 

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Most steel driveshafts will survive a lot of torque. It is the yokes and U-joints that are most likely the weakest links in a steel driveshaft.
Another very important factor to consider when purchasing/installing a driveshaft is the "critical speed" (max RPMs) that the driveshaft is rated for. Critical speed is determined by driveshaft material, wall thickness, length of the driveshaft, and maximum RPM the driveshaft will be spinning (remember to compensate RPM if you have an overdrive trans). If you spin a driveshaft over its critical speed rating.... BAD things happen.
 

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Discussion Starter #16
Most steel driveshafts will survive a lot of torque. It is the yokes and U-joints that are most likely the weakest links in a steel driveshaft.
Another very important factor to consider when purchasing/installing a driveshaft is the "critical speed" (max RPMs) that the driveshaft is rated for. Critical speed is determined by driveshaft material, wall thickness, length of the driveshaft, and maximum RPM the driveshaft will be spinning (remember to compensate RPM if you have an overdrive trans). If you spin a driveshaft over its critical speed rating.... BAD things happen.
The yokes and pinion and u joints are all 1350 rated. The driveshaft will be under 54 inches and is chormoly .083 thickness. I'll ask him what he will spin the driveshaft to, as I had to order the yoke from a different supplier for my application and he wants everything after I make final measurement.
 

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The yokes and pinion and u joints are all 1350 rated. The driveshaft will be under 54 inches and is chormoly .083 thickness. I'll ask him what he will spin the driveshaft to, as I had to order the yoke from a different supplier for my application and he wants everything after I make final measurement.
Sounds like you are getting good items. Just confirm the diameter of the driveshaft (based on the driveshaft length) will handle your max RPM you intend to spin the engine. Note that your driveshaft will be spinning much faster then your engine RPM's if you have an overdrive trans and plan to drive at high RPMs while in an overdrive gear.
 

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how to set pinion angle the easy way,set motor and trans to the required angle, place a angle finder on the crank damper read angle say 3* from vertical, place angle finder on pinion yolk adjust angle to the same 3*. there you go job done. unless you are drag racing then you will have to dial in a little less angle to suit pinion climb on launch.

cheers Ian 🇬🇧
 
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