Good question Sidewinder is a single engine concept I think? Two engines would be a little wide??? Dusty
The way we use to run two SBC is in phase - 180 degrees out. With aluminum rods there will not be the problem with harmonics that we use to run into with steel rods. Also, I am partial to a two groove piston with very little skirt.
Coupled together...not connected. Connected the harmonics will kill the front brg of the second engine.
The orientation is back to front. The pins do not slip in...they drop in from the side and are captured between the two halves of the coupler. This allows some floating and flexing. This kind of coupler is used a lot in the oil field to connect a series of pumps to a single diesel engine.
These couplers handle incredible amounts of torque and MUST be dependable. When I got the idea for this project I went to a tractor pull and asked questions.
HMMM? years ago we inherited a twin BBC rail, It was phased 45* out. Cyl #1 on rear engine was set to tdc half way between #3 & #6 of frt engine, firing order looked like. 1 8 4 3 6 5 7 2 _5 7 2 1 8 4 3 6 Had what appeared to be a giant Luv Joy coupling, dude was a machinist and mosy likely cobbled it himself, But i remember the thing idled like a rolls royce, even with big cams. Now the 4 carbs were a *itch!
Ran more like a V-16 than two V-8s? In the Navy we had patrol boats that had 2 522 BBC's. it sounded like a top fuel digger at idle. WAY COOL!!! But they were not coupled together in any way.. Dusty Hey would you post a couple of pics of the coupler?