454 - 4 bolt or 2 bolt main bearings?

Hi,

I have two 454 - 350hp built in 1988 in my 1989 Tiara. The port engine is leaking oil from, I believe, the rear crank seal. Problem is, I'm not sure if this engine has two bolt mains and consequently a two piece seal, or four bolt mains with a one piece seal as is the case with current engines.

I sent the serial number to Crusader, and they said the records back then were incomplete, but they believe it to be 4 bolt. Some old Crusader exploded view drawings dated 1987 say it has 2 bolt mains and a two piece seal. The transition from 2 to 4 bolt occurred sometime around then.

I'd like to pre-order the seal and oil pan gasket so I can be ready when I remove the motor, but what to order?

pgall:

my 86's were four bolt mains, Mark IV versions, with the two part rear seal. I don't think any of the newer stuff (Gen V) started to show in the marine markets until the early 90's.

Three options come to mind: 1) buy from a local supplier that will take back the 'unneeded' parts for no extra charge, 2) visit your local machine shop (or real good parts counter) and ask them what info they need to get you the correct parts and where to find it (many machinists use the data from the block), 3) buy both and sell the 'extras' on craigslist or ebay.

If they are originals, I'd be real surprised if they were other than Mark IVs.

Regarding the "artwork" in the factory manuals - they are notorious for "recycling" pictures. I've seen too many examples, from many different houses, where the pictures were 'technically' incorrect. The easiest one is using small block cylinder head pictures in the big block sections.....very common.

Unless they've been changed, they're 4 bolt main with 2 pc. rear seal.