Two k20's connected at the crank through a very short drive shaft. Cylinder 1 on engine 1 would fire at the same time as cylinder 4 on engine 2 (No joints though, unlike the picture, so it'd be stiff and wouldnt cause too much vibration. In theory.) then to an s2000 6 speed. From that to a CR-V diff.

two ecu's with both engines with the same tune producing the same power on cable throttle with a bar keeping the butterfly valves synced. Custom motor mounts obviously. Not sure if the picture is perfectly to scale but I tried my best.

One fuel pump, two fuel rails, possibly two radiators?

I don't know, I just wanna get some input on this cause I feel like it'd be a fun and challenging project, and a whole lot of fun in the end.
Please excuse the bad Photoshop lol

 

That pic is definitely not to scale. 2 K series would be 40 inches long, plus another 33 inches for the trans, and at least a few inches between them. So thats roughly 77 inches there. The wheelbase is only 98 inches on an EF. So youll end up with a driveshaft thats about a foot long, the 2nd engine will be entirely behind the firewall, and the driver will have to be moved basically to where the back seats should be... lol

I suppose there is nothing wrong with the idea of linking the engines together in theory. People do link engines together like that for tractor pull racing. I suspect the best way would be to use some kind of compliant joint in-between to hopefully deal with any conflicting harmonics/vibration and slight alignment problems.

Also, Idk why you would want to use a CRV diff in particular. It has a VC that would have to be disabled and is probably pretty weak.
If you are thinking CRV diff because there are already kits for converting civics, I think you are way underestimating how difficult everything else would be. The whole front of the chassis would need to be basically rebuilt from scratch to support longitudinal mounting and allow you to move the steering rack to the front side of the knuckles. Mounting an IRS or live axle in the rear is easy compared to that IMHO.

Sounds like a crazy amount of work to make 400hp. At this point it would be much easier to do an LS swap, and with that platform you could build an engine to make 600hp+ NA.

 

If you have to ask, then I wouldn't plan on an attempt to do this being successful.

 

If that's your EF, leave it stock.

Anything is possible but for how much fabrication you need, then try to make it run right, then the added weight. Not worth it, just buy a rwd car.

 

I've seen a lot of ridiculous threads but this one wins the award

 

Better option for packaging would be to run the two engines side by side with some kind of transfer case between them.

You wouldn't want to do the solid mechanical link end to end as discribed. That creates all kind of issues with shaft whip and harmonics. I would expect broken cranks in that configuration.

Again this is kind of a silly idea but car mods don't need to make sense.

Go have a look at the k48 V8 that is sort of based on two K series engines.