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Questioning the age on my engines / serial numbers

JCosta

Member
I lost me starboard engine this week on the way home from Oak Bluffs. Both engines were idling just fine for 20 minutes as I maneuvered around the marine waiting for my turn at the gas dock. As we headed out I slowly increased speed, at 3000 rpm I heard a load knocking sound so I powered down and turned the engines off. After the smoke cleared, literally, I was able to take a look at the engines. I noticed a large hole in the bottom of the oil pan.

More on this in a new thread so back to the question of serial numbers. I'm in the process of looking for a new long block and looked at my engine serial numbers to make sure I get the correct manuals. The tag on the engine displays the following

Boat is a 1982 Carver 3007

Starboard engine:
Model No. CH 220
Serial No. 35027

Port engine:
Model No. CH 220
Serial No. 35028

I noticed a number stamped in the block GM 3970010 - K10

attachment.php


Now when I checked the Crusader Marine Engine Serial Numbers page I don't even see my numbers displayed in a range. Can anyone help me to confirm the age of my engines. When I bought the boat I was told that they were original engines.

J
 
it appears you have the last of the '1981' production run...the service manual would be the 1980-1992 (+/-) version.

Its not uncommon for 'different years' of engines to go into a 'mismatched' hull (year-wise) on production boats. this is due to the quantity pricing deals cut between the engine OEM and the boat builders. Almost always, the engine is labeled with a year one older than the hull.

You should consider getting 350's in place of the 305's - the cost difference shouldn't be significant and the boat will perform better....and the other engine isn't likely to be too far behind...
 
This won't be conclusive evidence of having the original blocks, but there should be a casting date on the block. It will be a 3 or 4 character code. The first character is a letter that represents the month (A=Jan, B=Feb, etc), followed by one or two digits for the day in the month, and then a final digit for the year. On my 1977 Chev 350 cid engines, the date is on the surface of the block just forward of the flywheel housing between the distributor hole and the even-side head. In the photo, at the bottom center, you can see my block casting date: B 23 7 (Feb 23, 1977). You can also see the intake manifold's casting date (one day later) in the upper left. Each of the heads and the crankshaft will have casting dates using the same format, too.
CastDate.jpg
By the way, my block is also a 3970010. If you Google it, you'll find that GM cast a lot of them. Also, my 1977 Crusader serial numbers are 28774 and 28070.
 
Markomark,

Thanks for the reply, that's a good point. I guess when I didn't see anything prior to 1982 on the site I got concerned.

I had considered going with a 350 block but wondered if the 305 would lag behind to much. My plan is to replace the port side next year anyway. I figured if one engine failed then the other was not far behind.

Do you think my 305 parts will fit on a 350... risers, water pump, EST distributor, flywheel housing etc. Are the block dimensions the same? I guess I'm trying to save $$ where I can. My engines are RWC so I'm planning on going with FWC this time. This is going to be a great winter project!
 
DJR,

Thanks for the info I'll have to take a look for them. I was told by the previous owner that both engines had been rebuilt prior to him purchasing it but he told me a lot of things that proved later to be "false".
 
Do you think my 305 parts will fit on a 350... risers, water pump, EST distributor, flywheel housing etc. Are the block dimensions the same? I guess I'm trying to save $$ where I can. My engines are RWC so I'm planning on going with FWC this time.

Ayuh,.... They're SBCs,... Exactly the same, Externally,....
 
Ayuh,.... '86 is the transition year on the rear main seals,...

'96 is the year Vortec heads came out,....
 
Those blocks were used on 302 thru 350ci 1969 thru 1979. I have the same block on my 1966 Californian twin 350's. Mine obviously a re-power from sometime ago.
 
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