TKO600 and driveline vibrations

[Dinorider]

I have a 65 mustang with a 306ci Ford small block with Total Control Products motor mounts, a TKO600 transmission (American Powertrain), the X-brace for the tranny, a Strange Engineering Ford 9 inch diff with 4:11 gears on TCI mideye leaf springs, and GT shackles (1 inch longer than stock shackles).
I had a vibration at 60 mph and I checked tire balance, axles, brakes, have new u-joints, balanced the driveshaft x 3 (don't ask), finally checked driveline angles and there was the problem (nobody I had talked to knew much about driveline angles so I have had to educate myself after the fact).
I managed to move vibration up to 70 mph (5th gear) by inserting 2 degree shims to give (Note-measured with body 1 degree down front to back) 5 degree down angle at diff (pinion up). My working angles on the front U-joint are 3.1 and the rear is 2.8. I have shimmed the TKO tranny up 5/8" and it is now as far up as I can get it and the angle is 5.5 degrees down. I know these operating angles are at the limit and are probably the source of my vibration.
I have read that the TKO600 in a 65 needs to have the tunnel cut (American Powertrain says no but I now know otherwise). The car is finished and has dynamat in the interior so that would be a messy problem. I was wondering if anyone has done the double cardon joint or CV joint driveshaft conversion and if so where did you get the driveshaft and how did everything turn out. I asked Ron Morrison about drop motor mounts and he didn't think that would give me the angle I need. This is the last real gremlin my car has and had me chasing my tail for about 3 years now. Help would be appreciated.

[csouth]

Andrew has done it on his GTO

https://www.pro-touring.com/threads/...ion-2-0/page30

[Dinorider]

Hey thanks, looks like he has had great success with this.

[andrewb70]

I also run a double CV shaft in my 67 Cougar. Mine has a LS swap with a T56. The DriveShaft Shop makes a CV pinion yoke for the 9" rear end and CV slip yokes for most popular transmissions. Check out my Cougar build thread for details.

Andrew

[Dinorider]

Couldn't see any driveshaft pics, what were your driveline angles? My local hot rod shop is going to lower my motor by refabbing my motor mount plates first. Hope it works otherwise the CV driveshaft is next. Do you mind giving a ballpark price for your driveshaft?

[Dinorider]

Well I didn't realize your post was so long. I am impressed by the build and your talents on the cougar, that car looks like a lot of fun. I will post after the motor mounts are lowered to see if that solves my problem. If not then the CV joint driveshaft may be my next move.

[andrewb70]

Keep us posted.

Andrew

[Dinorider]

Got the car back today with the lower engine mounts fabricated and installed. The vibration is greatly reduced and can cruise at 70 without any of the rhythmic vibrations I had before. On deceleration I do hear some vibration so I will need to tip the pinion up a little more but the motor mounts have made a huge improvement. Pleased so far and will do a little more fiddling with the pinion angle to get it as perfect as I can. If this didn't work the CV driveshaft was next.