So I've lagged a little bit on the update, but last weekend my brother in law, Justin and I set about pulling the head of to inspect a suspected head gasket failure. We had found that there was little to no compression on 3 and 4, although bizarrely it seemed to run fairly well when we first fired it up and only dropped cylinder 4 later down the line. We had around 120psi on 1 and 2 which seemed low so had planned to do a valve job at the same time.
Turned out the head gasket was indeed blown! In a big way!
We did a valve job, replaced the valve stem seals as we went, and bolted the head back on to get a compression test done. Cylinder one was slightly low at around 150, but the rest were all up at around 165. I was fairly pleased as the Haynes manual of lies claimed 170 from the factory.
While the carb was off I went round and blocked all of the emissions related vacuum lines, leaving only the stuff like vac advance to the distributor, and the 2nd barrel etc.
Bolted it all back together and what do you know, started right up and ran like a dream. Great news!
Later in the week we set about rebuilding the shifter as it felt like stirring a porta potty full of frozen turds. The slot in the ball on the bottom of the shifter was worn slightly so was never going to be anywhere near nice, so a quick eBay search and we found a short shifter from an rx7 which looked like it would be the right part based on the picture, for $17.49 I decided it was worth a shot. That'll hopefully show up in a few days.
Finally, a guy from my work kindly gave me a magnafuel fuel pressure regulator.
It's built for n/a carb motors, however I contacted magnafuel and asked about switching the top for one with a boost port and whether it would work under boost. It's $35 for the new top, and it will work just fine under boost! More great news!
Next job after the shifter is fitted is start hunting for a turbo and manifold. Its my birthday next week and I've asked for Home Depot gift cards, if I get enough to make it worthwhile buying a welder, I may build an exhaust manifold with a t3 flange rather than go for an f2t manifold, which should open up my options for turbos.