Pacemaker Boat Owners Association

These are the manifold casting numbers and not the block identification numbers. This site might help.
http://www.yearone.com/updatedsinglepages/Id_info/gm_engine_id/engineinfo2.html

Crusader (if that is what they are) put their engine identification plates just above the flywheel toward the distributor.

3970010 is a 4" bore block casting number - anywhere from 302, 327, 350 ci - just depends on what crank was stuffed inside. Most were 4 bolt mains.

346250 is the intake manifold for a '76-'82 4 bbl motor, 305 - 350 ci.

http://outintheshop.com/faq/casting/castings2.html

You probably have 327 or 350 ci motors there but won't know which for sure until they're broken down and the crank part number checked.

Cheers, Mark

thanks for the help guys i really appreciate the info! will update soon