How can you find out the size of an inboard motor?

Discussion in 'Boat Repair Help' started by Army Guy, Sep 8, 2008.

  1. Army Guy

    Army Guy New Member

    I recently purchased a boat with a GM motor. I can not tell if its a 350 or a 305. I have looked for a ID tag but cannot find any numbers. Am I just missing it?

    Any help would be :0a31:
  2. chambers bd

    chambers bd New Member

    Check the heads on the back, Is it a Vortec?

    The motor number should also be on it maybe on the side.

    I always thought the heads looked small on a 305.

  3. roadkill636

    roadkill636 New Member

    warrenton misso
    about the only way to tell is by the casting # that will be on the top right side of the bellhousing area right behind the head if your you have the front of the motor at your knees . they used SO many heads on their small blocks the strohe is the samebetween a 305 & 350 a 305 has a 3 3/4" bore and a 350 has a 4" bore, the first year for a 305 was 1975
    most 305s wer 200-210hp 350s were 230hp in the 70s -80s
  4. jrack1

    jrack1 New Member

    Engine Code Stamping Numbers
    All engines are stamped with an engine ID code, consisting of assembly plant code, production date and suffix code. V8 codes are stamped on a pad just forward of the right side (passenger) cylinder head. 6 cylinder engines are stamped on the passenger side of the block behind the distributor.
    Click here for Chevy Engine Code Listings

    The engine date must precede the car build date, otherwise something is amiss. Some engine machining operations (decking) will obliterate the engine ID.
    Engine ID Code Example: V0101CLJ - (V = Plant, 01 = Month, 01 = Day, CLJ = Engine Suffix Code)
    Another example: T0830CTY - (T = Tonawanda, 08 = August, 30 = 30th day, CTY = 1970 396 Camaro, 375 hp, 11.0:1, TH400) CodeEngine PlantCodeEngine PlantFFlint (Motor)SSaginaw ServiceHHydramaticTTonawandaKSt. Catherines, OntarioVFlint (Engine)(McKinnon Industries Canada)MGM of Mexico
    try this link