Drivetrain Angles... too much for the street?

When I set the engine and transmission in place, I set the angle at 3 degrees. Did the same with the pinion. The u-joint angles came out to 1.8 degrees. So, I sat the body on the chassis this afternoon to make some measurements on the rear frame. When I walked around to the front, I realized the cowling was higher than the engine, a lot higher than I thought it would be. From the top of the intake manifold to the cowl is nearly 9 inches. And that is with a 1 inch spacer. I started to think I might need to raise the motor and transmission up 3 inches. It would look better and give me 3 extra inches between the frame rails and the headers, once I build them. But, if I raise the engine and transmission and keep the same 3 degrees, the u-joint angles will be over 9 degrees. My question, what is too much drivetrain angle to use on the street? The new angle of the driveshaft will increase from 4.8 degrees to approximately 12.8 degrees. That would mean I would need to set up a 10 degree drivetrain/pinion angle to end up with 2.8 degrees at the u-joints. At 5000 RPMs, the max angle for u-joints is around 3.25 degrees. Now, I measured the engine angles of several side view photos of actual alter dragsters from the 60's. The engines were angled from about 6 to 10 degrees, but they were not street cars. I feel 10 degrees would be pushing it. I know many inboard boats have engine angled close to 10 degrees when moving. I can replace the stock mid-sump oil pan with the rear sump oil pan to take care of the oiling pooling at the rear of the engine. Not sure about the manual trans. Another option is to lower the body over the frame 3 inches, but that causes problems with the fuel tank, rear tire clearance and seats. Or, just live with it. To bad no one makes a tunnel ram for BB Buicks. Any thoughts would be appreciated.

 

Out of phase U/J's contribute more to drive line vibrations than an extra couple of degrees ever did.

 

Look up drive line post by me on this forum
A u- joint has to have an angle for to work properly. Measure the angle that the input yoke to the driveshaft is when fully bent and won't move anymore. Any angle will work as long as the yoke doesn't hit the driveshaft.

With your engine and transmission combo, you will have to make decisions as to looks, ride, drivability.
Can't wait to see it finnished. Good luck.

 

Thanks for the posting, T-Test. I have read hundreds of posts over many different forums and it is surprising how much counter intuitive information is out there. Even among the 'professionals' there is not consistent terminology. I knew about the max RPM angles for u-joints as well as phasing. My first setup was just over 1 degree, to keep the u-joints working. The new setup will keep both angles at or below 1.56 degrees, on paper. Funny enough, I used two jack stands and 2x4 to simulate the driveshaft and the measured angles were close to the calculated angles. I may shim or adjust as needed once I actually mount the driveshaft. As for the difference in position, below is an image of the engine before, left side, and approximately the engine angle to the right. The right is more what I wanted so...