Apologies if I'm resurrecting an old thread!
If it helps, I have a '91 Econovan which might have the same engine. Mazda FE 8v SOHC.
Mine was gutless too, so I did a few cheap-ish things and now it pulls really nicely.
The exhaust had some rust issues, so I got 4:2:1 extractors and 2.5 inch mandrel pipes, a Coby sports resonator and Chase sports muffler. Done at Midas. The van was very noticeably happier after that. I guess that probably cost around a grand at the time but if your exhaust needs replacing anyway then that's not too much more than a full exhaust. I think 2.5 is a tad big, would stick to 2.25 if I did it again.
Next up I got a Power Spark points replacement electronic ignition off TradeMe. Idle was really smooth afterwards and cold start was really obviously easier. I think that was around $100.
Finally I had Franklin Cams modify my camshaft and resurface the followers, after telling them what I was wanting, being more grunt pulling uphill and for overtaking. Huuuge difference after doing this, cost about $400.
Spark advance could be increased substantially from stock also, which makes a noticeable difference again.
Next up, nobody knows wtf to do with the complicated carb it has stock so I want to find somebody to help me fit a pair of SU HS6's I have that came off an old Triumph 2500
Yes, the stock motor is shit, and you could drop in a Kia Sportage FE3 or a Holden 3800, but you can actually get it to breathe great by gradually doing bits here and there.
Hope this helps