I've got my bastardized 13B with GSL-SE housings and old REPU or RX-4 endplates (non-nitrided R5 casting). I'm going to repaint the engine while it's assembled, so I'd like to get the waterpump off. If I recall correctly, though, the gasket for the waterpump is different on old blocks. Does anyone know if this is the case? Can I still get an old gasket if there is a difference?

What I'd really like to do is put a FC aluminum WP on there, but don't know if the hole patterns are the same. Does anyone know what my WP options are to go on R5 irons?

 

pre-86 (12-A & 13-B) water pump housings are fine. Besides, if you want to install an aftermarket water temp gauge, you can tap the back of the housing with 3/8 pipe where as on a FC/GSL-SE, you will have to enlarge the hole and tap it with 3/8.

 

Are there any Pre-86 water pumps in aluminum? It looks, then, like any water pump will fit, though I remember that one bolt moved in 86, I think. Is the shape of the waterpump/endplate flange the same, then? I could have sworn that they used to be different.

 

no pre86 aluminum water pumps. i've seen FC waterpumps on 1st gens, guy said it saves 20 lbs?

 

I had an FC pump on my 12A 1st gen too, but didn't know if my endplates are the same pattern as the 1st gen. If so, I'm in business.