BluePrint MBP3550CTC GM 355 Dressed Marine Engine, Cast Iron Vortec Heads

The BluePrint MBP3550CTC starts from the same 355 cubic inch marine short block as its base sibling, then dresses it out: carburetor, intake, distributor, and plug wires arrive already mounted, so this new engine lands closer to a turn-key install. BluePrint rates it for 390 ft-lbs of torque alongside 365 horsepower at 9.5:1 compression.

What dressed means here

On top of the cast iron Vortec heads, this package adds a fuel pump, a fuel line and filter, a cast iron circulating pump, and a 600 cfm electric-choke carburetor, built around the new cast iron marine intake; a rubber-coated steel oil pan and dressed-up valve covers round out the outside, while spark plugs and BluePrint wires finish the ignition. The rotating assembly pairs an externally balanced cast steel crank with hypereutectic pistons and Hastings moly rings. Bore and stroke are 4.000 inches bored .040 over by 3.480 inches, and the cam's intake duration is 218 degrees against 224 degrees on the exhaust side.

Setup notes

Does it need a zinc additive? Yes, BluePrint specifies one for this flat-tappet-family valvetrain. What oil is recommended? 10W30, non-synthetic. Is it EGR compatible? No. Each engine also ships with its own dyno results, so you can see how your specific unit performed before it left the shop.

Warranty

Coverage is 12 months, unlimited hours, for pleasurecraft use only; commercial applications are not covered. Part number MBP3550CTC.