It's actually quite common in the Porsche world to transplant a Chevy engine. Though I will have to say most that do it use an LS based engine. I just know that the transaxle required to handle the torque of a V8 are expensive.
Location: Guilty of federal crime of loving Mexicans because I'm a liberal bitch in Sahuarita Arizona.
I built one of these LT-1 944s for my brother. Done right too. $800 radiator, fully built engine with well over 400hp, all the Renegade Hybrids options like $900 3/4 length headers, front springs for the added wieght, upgraded torsion bars, etc, etc, etc. It's better on paper than it is in reality. The transaxel exploded in short order and we had to find a very rare 951 limited slip unit. The conversion requires going to manual brakes due to clearance. We installed 951 front brakes, but they are not enough. Braking is an adventure. 993 turbo brakes are needed at > $2,000. Even with the new springs, torsion bars, and 951 sway bars, the handling is sketchy. We have yet to get that sorted. Hose/wire/belts/hood clearances are rediculously tight. Makes showing off the difficultly of install fun though. Fast? YES.