It’s a bit of a bit moment as, in Section 10, the the monocoque body, the undertray and the engine are married together!
The instructions don’t seem very specific about the order in which these assemblies should be joined; I tried a couple of things but the winning approach was to join the engine to the firewall first, then join the body/engine to the undertray as a unit. I think any alternative will fail as there isn’t room to move the engine backwards in the undertray, so its mounting pins could never have room to engage the holes in the firewall. That said, for those starting this model, there may be an approach where you don’t fit the side pod engine mounts (M86/M87) in Section 4/5, but fit them AFTER the marriage. This might allow the engine to be mounted in a different order.
Anyway, there are a lot – in fact, I count 11 – pieces from the engine that need to be fitted into the firewall. There are so many I made a map of what went where, see below. With the approach of joining engine to firewall first, all 11 dont’ have to be done at once (phew!). I suggest:
- Mount the engine to the firewall using the big mounting pins on the engine block assembly – parts M294, M253, M252 – and the right hand mount (which was captured between the engine and transmission when they were joined in Section 9) – part M89.
- Fit the left hand mount, M88.
- Fit rhe shift linkage, M162, which was also captured between the engine and trans, to the firewall and then to the rear of the transmission.
- Fit the two thin linkages, M114 and M115, to the firewall and engine block.
- Fit the remainder. The X-brace, M21, and the two pipes, M159 and M161, can be fit now or after the body/engine is married to the undertray. I did it after the marriage so there was more access to the top of the engine for a while, to add pipework and cable ties.
Before the body/engine can be married to the undertray, wiring for the LED lighting has to be joined and tested. The wiring passes from the left side of the body, down through the side pod RE4, and through a hole in RE4 out to the engine bay. The wiring that can be seen in the engine bay, leading to the rooftop alert lamp and to the rear lighting cluster, is thus functional!
The body/engine and undertray assemblies, with wiring passed through the side pod and joined. The body/engine will be turned to face the other way and then is placed onto the undertray. 
The car, just after marriage of the body/engine and undertray
All the various piping can attached and/or routed around the engine bay. Section 10 also includes fitment of the small forward section of undertray, along with the pedals, so I did that too. I’ve also added some extra parts from Section 11 – the parts that hold the light cluster to the undertray, and also the water bottle and its associated piping. So here is something that looks like a car:
I have not completed all of Section 10; still remaining is the hardware (air intake, radiator) on the rear of the two side pods. My plan has been to do them after the marriage so I can fit them to the now joined body. It may have been a better plan to try to fit everything together earlier… but I’m stuck with my plan now.
From this point, the remaining parts for Section 10 can be prepared, along with the rear cover which mates with them.
Jason's Mazda 787B Build 