I have an 87'. I added 225/75/15s, and it was "anemic" at best climbing
hills. The disadvantage is you are going to downshift. The only advantages
in my case were

1) it made the speedometer 100% accurate. :-)
2) I was going faster in each gear. So I may be in 3rd gear, but 50mph
wasn't a huge problem.

I solved the problem with the addition of a turbocharger system.

In your case, I don't think "bolt ons" are going to cut it at the elevation
you are at. The power you need is in the 2000-3000 range, and most bolt ons
affect 3500up.

If you are going to stay aspirated, a corrected 3rd and 4th gear would be
wise IMO

I recommend you put the tires on first (or at least BORROW some), and see
how it is with stock gearing before you throw down the $ for a trans. You
want to get the gearing right the first time!

John
Aircooled.Net Inc.