There are owners on the volvo message boards that have their 7-series volvos in the mid to high 14's with upped boost and freeflowing exhausts.

Best engine in the 80's is arguably the '84 B23FT that came in the 7-series. It had a forged crankshaft large main bearings and stout rods. People who own the 240 series turbos strive to swap in the B23FT.

The B230FT from '85 up to mid 88 sucked, weak connecting rods.

Strongest of the B series blocks came from late 89 on up. These engines reverted back to the B23FT design and improved upon it by beefing up the rods even more.

The weak link in all this is Volvo transmissions. The manual tranny is not up the task of a 250+hp car. There are swaps for a getrag, but they're pricey. The automatic trannies are stronger in a sense, but also slower without a higher stall converter.

I've owned an '82 242 Turbo, added an intercooler, newer intake manifold, full catless 2.5" exhaust and upped the boost to 10.5. I ran decently, might have broken into the 15's at the track, haha.