69 cougar XR-7 build

hi guys
i have a 69 XR-7 i’m working on . totally disassembled it (every nut and bolt out) and am in the process of building it . working on installing a 351 cleveland and 6 speed tranny rite now . my question mite sound stupid , does the center line of the drive train run centered on the front and rear frame rails , or is it offset in the tunnel ?

Dimensions seem right but the proportions are off on that drawing. In any case no modern car has the drive shaft centered, other than the drive shaft is centered in its tunnel. Hypoid rear axles are like that.

ok , so you say the center of the yoke on the tranny is centered between the front frame rails , and the pinion center line is offset to the rear frame rails . rite ?

No one said that. Except you.

Maybe what you are really needing to know is what rear mount works for your transmission? Which one do you have?

the 351 is bolted up to a borg & warner T56 . haven’t found anything that bolts up to it , so i have to build a mount to weld in .

Modern driveline has one. Might be more expensive than you want but it should give you an idea. Basically you are centering the transmission in the tunnel. 65-70 Mustang Uni-Cross Crossmember for T56

i already spoke to to modern driveline , tremic , and lethal performance . they don’t have a mount works for m tranny . i have an automatic mounting bracket , but i don’t know if the automatics center line is centered between the 2 mounting holes on the bracket . this way i would have a base line to take my dimension from .

Stock nine inch driveshaft seems centered left to right at the trans and at the pinion flange. See photo. I believe it is the ring gear and differential that are offset as the axle shaft lengths are different lengths.

nice job . i had no engine or tranny in this car when i started this project , so i’m not sure where they actually sit . i see the pinion is offset to the right side . would you be able to tell me if the center line of the tranny is centered between 2 front frame rails .where i would be able to position the tranny in the rite location to weld in a bracket for the 6speed tranny mount the tranny i am using is from a dodge viper . so far , the drive train fits without any tunnel modification kit (which involves cutting and welding) .

No it isn’t.

That makes sense! Thanks for posting that picture.

You don’t want any side driveline angles also referred to as compound driveline angles. For automotive ujoints we are really only measuring the vertical angles to make sure they are similar front and rear. There’s way more to get in, but typically you set the engine angle to 5 degrees and the stock nine inch pads take care of the rest. The front and rear angles should be within 1 degree of each other and no angle should exceed 3 degrees. That says nothing about compound angles where the front and the rear sit offset to each other. This type of arrangement requires the use of a plumb bob and software from Meritor to figure out. You are probably going to have tunnel modifications to make to keep proper angles.

my daughter researched this , because i’m not good with computers . she found out that engine and tranny are set at 1 1/2 degrees to the passenger side .thats for 69 mustang and cougar .

your going to have to make your own mount. I used the same trans in a 62 chevy.
center the engine trans and go with that. if your using non adjustable engine mounts, its easier.

when you installed the viper trans , you say you centered it in the tunnel ? how did it work out for you ? what about vibration ?

I centered it where the original trans was. Although X frame Chevys use 2 driveshafts. I dint use a one piece. it goes to a 9 inch

thanks for the input.

The viper T56 trans mount is not flat, it is at an angle, so you have to build a custom mount. bolt the trans mount pad on, then build from there.