Macs Garage
OBS Enthusiast
First time posting, but following for a long time. I have a 1999 GMC K2500 "classic" with a 5.7 vortec. The speedometer was broken when I bought 2 years ago reading 161,000 miles, so actual mileage unknown (speedometer and odometer working now). The engine went out this summer. I didn't have time to mess with it so took to a local shop with ASE mechanic. They were going to put a remanufactured engine for me and put a towing cam in for me ( I wanted more power full pulling my fifth wheel). After a week of searching they couldn't find any from a vendor they trusted and said nobody even had cores to rebuild. Finally they found one at a GM dealership in California which they bought through a local GM dealership they buy through. I was told it was an engine built to go into RVs 340hp and 350#tq. The only paper work that came with it was a pretty generic installation guide calling it a GM Performance L31 HD. When I look go to the GM Performance web site it doesn't state any specs for HP or torque. I questioned them about it and they said the 340HP 350#tq engine is what GM told them it was and it was built for RVs. Has anybody heard of such an engine?