beef stew,
cool project! i have 2 used 181 (3.0L) from forklifts. they are great motors. you are correct, they have a SBC bore and bolt pattern for bellhousing. they also use a 1 piece rear seal in later motors. i also have 2 new crate engines.
i have a few questions for you.
what rpm range do you plan to run?
what rpm do you want full boost?
cam specs?
the stick shift will hurt the turbo/boost on shifts. i am sure you know that allready. i also think a t3 exh housing will support the 181 motor.
i run the 62-1 on a 292 for street use. it will boost fast and i have had to increase the exhaust housing to slow down/control boost better.
have you thought about using a turbo from a buick GN. 3.8L is awlfully close to the size you need. they are cheap to try also.
have you allready picked up a fontana head?
tom
