so, i have a 72 1800es, and it's my daily driver, today, i took it on a 2 1/2 hour interstate trip, even with overdrive, at 80mph, it's turning around 4300 rpm. needless to say, it's a little noisy, gas mileage is not that great, at that speed. and we all know the b20 in an ES is not exactly a powerhouse, not to mention, first through third gear in the trans is making noise.. so i'm thinking an engine swap. trouble is, there's really not a whole ton of information on these cars, as far as that goes. i'm wanting to stay 4 cylinder. and the two engines i had in mind are the motor that would be in an early-mid 80's volvo 240 turbo, or a ford 2.3 turbo. i think it would be cool to keep it volvo, i'm definitely wanting to go the turbo route. i don't guess by chance, the volvo motor would be a bolt in, or close to it deal? the 2.3 ford is also alluring, they are tough as nails, can make great power, good aftermarket, etc.. i work at a hot rod/fabrication shop, so making mounts is not a problem. but i don't want to cut or hack anything in the car for clearance. pretty much not interested in doing anything to the car, that can't be "undone"

with either of those, i could step the rear end gear down a good amount. so anyone care to chime in?