Matt, the A series auto bellhousing supposedly doesnt require much of a 5-8mm plate to mate to a T50. Im sure DD gonzales can find my thread where I tried to get one of the guys who did it but failed to get decent prices from a waterjet place.

I would love to see the flange idea.

I have tons of 19.05mm 6061 plates on the floor with enough surface area to do an adapter flange.

Flange idea? Do you mean the adapter plate for the A-series auto bellhousing, or something to do with the driveshaft?

Yes that is what I mean.

I am doing a T50 adapt to my A12

I think I can do something very similar

Maybe with two pieces.

I bought an auto bellhousing for the "one day" when I adapted a tranny with better ratios. The T50 is a good box nut I'd love to see someone do an adapter plate for a Miata 5 speed. The 5 speeds can be had stupid cheap. The bolt circle on the Miata trans is larger than the A series so a plate might work. Of course at the end of the day it's likely simpler to do an adapter for something like T50 or Ford Type 9.

six speeds are better than 5 , at least for a street car. My next 1200 will have a six. Better acceleration + more fuel economy. And cheap. The Miata six-speed is an Aisan AZ6 -- surprise! So is the Nissan 6-speed

EDIT: also an AZ6 -- Toyota J160 for 1G & 3S engines (E10 Toyota Altezza/Lexus IS200) also Toyota 86/Scion FR-S (subaru boxer engine)

$300 for an MX5 trans in the local Craigslist. Not a bad pricing but not the best for sure.

The 5 speed is smaller and lighter than the 6 speed. Also the 5 speed ratios are the same as a mid close 4 speed. I used a mid-close box For many years I used a mid close box and on my moderately tuned motors it worked well.