I'm thinking that my 83 needs another gear, mostly for the highway. I'm thinking about swapping in a 5-speed, but it occurs that I'd have to fab up a custom crossmember. Is this correct? would it be easier to put in an EA82 at the same time (doubt it)?

The ASRM has a step-by-step process for this exchange.

4th in yours is the same as 5th - so you will gain little, except at lower speeds, and for passing etc.

 

GD

4th is tha same as 5th? why does my hatch cruise at about4k rpms at 80, when my ea82 is at about 3k? you sure about that gd?

Yes, Your highest gear on both tranny's are 1/1 , meaning 1 rotation of the motor to 1 rotation of the drive shaft.

 

4th on a 4 speed is the same as 5th on a 5 speed.

Allmost all tranny's are like this, highest gear 1/1.

the gears aren't 1/1. the tallest ones are overdrives.

 

Gear Ratios

http://www.ultimatesubaru.org/80s/mick/gears.htm

 

Swap Instructions

http://www.ultimatesubaru.org/forum/article.php?a=37

 

I followed the instructions and put a 5 spd D/R from a '89 SPFI wagon into my Brat.

 

if you want to maintain the stock interior, Bratsrus (Jerry) makes a kit to make it all a bolt on deal.

Hey Scoobywagon This is Jerry, if you were at the show i had a 5 speed kit with me. I make a 5 speed kit that lets you swap everything over without any cutting or welding just unbolt and bolt it back in. You need to get your drive line lenghten thats it. Let me know if you want one. Thanks Jerry