Thanks guys!!!

After reading the last few posts and thinking about this half the night I went back down to the shop, mocked everything back up and took the measurements myself.

All the dimensions are the same between the 3.0L and 3.5L. So, yes, the bell housing, clutch, flywheel and 3.0L manual transmission starter from the 3.0L absolutely will bolt to the 3.5L engine without any modifications or special parts.

The difference is in the backing plates for the 3.5L automatic and the 3.0L manual. THAT is where we went sideways. Instead of using the transmission bell housing or manual trans backing plate to check everything they were using the backing plate from the 3.5L automatic. <img src="/forums/images/graemlins/notooth.gif" alt="" /> Of course, it offset the starter slightly outboard. Their measurements were also out of wack on the engagement. I have no idea what happened there. This is why I dislike not being able to do this stuff myself. <img src="/forums/images/graemlins/frown.gif" alt="" />

The manual transmission backing plate still would require a lot of tweeking, though. There's just too much of a difference between the back of the 3.0L and 3.5L and the oil pans. Its easier to take a dremmel to the automatic backing plate to move the holes slightly inboard for the starter than try and weld in a bunch of sheet metal or make a new backing plate.

So, all that's resolved. Only thing left is to drop it in the bay and see what there is to do with the motor mount brackets.

Again, thanks guys. The jog to my thinking was very helpful!

Edward

[edit]
I did speak to several places that actually do make flywheels. Useless exercise though that may have been. <img src="/forums/images/graemlins/frown.gif" alt="" />

10,000 RPM
$450 for the first flywheel, $400 thereafter. You supply the starter ring gear. They'll make a lighter one or a heavier one, per your specs.

Fidanza Engineering
makes Mitsu flywheels; apparently already makes a flywheel for the 3.5L.

Standard Flywheels
you supply the starter ring gear.

All of these are steel flywheels, not aluminum.