Best year(s) 904 for a street/strip car?

Another thing on the back burner, After I get the rear diff sorted out (eBay used 3.55's are whiney junk!! replacing this week with a virgin set) we are going to start the Magnum swap.
At first this will be on the '66 904 original to the car (18 spline converter) which works fine, but if i am going to go into it to better suit the Magnum set up I think it makes sense to build a 27 spline trans to have a better choice of convertors, etc.
Plus that will leave me with a fine running 273 2bbl/904 combo to put in Dads '48 dodge?

So, what year/years would be the best to look for? Car is a'66 Barracuda weighs 3400.
3.55 rear and will be driven to the track about 40 min away on the interstate at 65/70 mph.
Will NOT be a manual valve body.
If i know what to look for, while Dany and I are busy with the motor, I can keep my ear to the ground, I know I can kick up a good core to go through, if I know what year range to look for.

Again, thanks for all your help guys!!