The way i see this one is a mild engine up front in the usual position for picking the kids up from school. getting the groceries, driving to work etc and a wild one in the back for having fun, going fast and leaving rubber on the road.
Two engines, each with a clutch and one manual transmission. Transmission more or less in the usual position with a transfer case between it and the front engine's clutch. Rear engine, mounted over the rear axle, drive taken by shaft from its clutch to the transmission via the transfer case.
Drive from the transmission to the rear axle by shaft in the conventional way.
To drive on the front engine lock the rear clutch disengaged. To drive on the rear engine lock the front clutch disengaged. Two clutch pedals I think.
Each engine will have its own separate fuel and cooling system.
Front engine will be a stock 327ci Small Block Chevy. Rear engine will be a supercharged 421ci Pontiac. Transmission will be a Chrysler A883 four speed manual. Rear axle will be a Ford 9".
All this will be mounted on a modified '58 Edsel chassis which will carry the 1965 Chevy El Camino shell.
I will be combining parts from the kits below, some resin from
www.thepartsbox.com and bits from my parts boxes.




So far I have glued the SBC engine halves and put some filler in the big hole through the sump where the front axle passes (yes, its one of THOSE kits...), lobbed some of the chrome plated Poncho parts into the stripping tank and put filler where the top of the Edsel framerails is moulded open.
The Edsel chassis is one I bought part built which had been glue bombed. I had to remove the front suspension with sprue cutters so the parts didn't survive and i'll have to build something up from what I can find in my boxes of bits.