Hello everyone!
We're looking after swapping the engine of our 660thousands km Volvo 360 GLS. The engine is running well, but after all those kms, we feel it can hardly run more than one endurance race (we participate to 8-to-12 hours endurance races in Italy).

Maybe we'll give it a try with the first race, but sooner we'll have to swap the engine.

Our original B19 is a carburetor one, and we'd avoid complex swapping adventures... so the question is: what kind of engine would you suggest?

Our goal is to have a nicely torquey engine, with some 140-160 hp. It has to be quite fast, but gentle with gearbox and transmission and has to be very reliable. It won't need to rev at high rpms: the tracks where we race are small tracks with short straights (typically the organizer will place chicanes to avoid high speeds).

My first choice was a 2.3 carburetor engine (a B23), but these are hard to find.
Turbo engines I feel they are too torquey and might generate problems on the transmission.

What would you suggest as the "easiest swap option"?
Thanks!