Wanted engine for Kyosho Landjump Integra

Looking for an engine for my Kyosho Landjump Integra, a vintage 80s one that would make use of the Integra's muffler. Anything considered really as am unsure whats what exactly, I just know that the 2 engines i already have are not right as one has a muffler fitted already and the other one the exhaust out is on the wrong side.