Hi John, sounds to me like you've got a pretty good setup. With the 3.27 R&P, the .86, the tall tires and more vehicle weight you should have a good match. The 4.03 low will be a little short but she'll launch real easy and the
.86/3.27 should give you a nice reasonable cruise.
I tried a 3.08 with a .72 and 29" tire and it was too tall....could have made it work with a .86 but just bit-the-bullet and went with a drum 3.42 which works great...but I gave up posi/disc.
My 3.42 let's me cruise all day at 65-70 at 2K and I added a little breathing and improved fuel delivery and am hoping to get an honest 20-21 mpg. The best part of the whole mod is that now the little engine, with the 5 speed can stay in the torque band without a lot of free-winding. I don't have to putz along in the "Buick" lane with the other old farts!!!! No need for a SBC and a slushbox!!!! She purrs like a kitten but has a little TIGER in her when I ask for it!!!!
Don't forget to slide your disc on the extended splines to MAKE SURE it will have the extra travel. That is the key to making it work!!!
Let me know how it works out.
Dave
