NO serial numbers?

trimta said:

I have a 5.7 mercruiser 350 vortex motor with a 4bbl carb, Can anyone out there tell me how I can tell what year & model this motor is. The owner told me that it may be a 1990, he bought this as a create motor short block & built on it from there, with the vortex heads & ect. The only numbers I found were the engine casting #'s 10243880 and the eng. size 5.7 cast in mexico.

Chevy Tech shows cylinder block casting #10243880 as a 1995-1996 5.7L Gen 1 crate engine.
They also show that it will be fitted with the OEM 10172839 Full Dished pistons.
Another site suggests: 1996-2000 SBC 350 2 or 4 bolt main and ZZ4, roller cam, one piece rear main seal
Super Chevy site suggests: avoid iron Vortec cylinder head casting number 10239906, which has a modified exhaust seat and loses 20 percent of its flow at 0.120-inch lift.
Another site suggests: 10243880...350...95-00...2 or 4 bolt mains...Vortec ,Gen.I,roller cam,one piece

You may want to do your own search, as I cannot verify the accuracy of this info!

I did notice the port where the fuel pump would be was sealed at time of casting. This motor runs off a electric fuel pump.
Yes, this occurred during the time that Automotive SBC engines no longer used carburetors.
The Marine versions went to the electric fuel pumps.... which must also have the N/O Low Oil Pressure switch in the loop!

I looked for the serial # tag & couldn't find it. There is a sticker on the oil pan, but to hard to read. Thats all I have. Anybody out there help me? THANK YOU!
What is it that you plan to do once you have these specs?

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trimta said:

Thank you guys for the info., This motor was placed in a 1985 22' formula, the guy I purchased it from replaced the 1985 motor with this 5.7 350 short block. He added the vortex heads W/aluminium 4-bbl. manifold.
FYI.... if the Engine is Raw Water Cooled, an aluminum intake manifold must have the bronze lined coolant passages, or it will begin to fail in short order.
In other words, DO NOT use the Automotive version "aluminum intake" if this Engine is raw water cooled.

The intake has the 8 bolt to the heads so I know it does have the vortex heads. Reason I need to get the right year is the only thing he added new to this motor was the heads & intake. All other parts came off that 1985 motor
Yes.... that could be a concern.
The GM full dished piston "volume" must be correct for the 64cc or 65 cc chambers of the Vortec cylinder heads.
If this is not a good match, the engine may produce an incorrect static compression ratio.

This is why I mentioned GM Full Dished pistons earlier. For those of us with Engine building experience, these types of things are of importance!

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trimta said:

As far as I can see because the intake is bolted down there is a bronze ring in the base of the intake in the thermostat seat, is it safe to say this aluminum manifold is for marine application?
Here is an Edelbrock intake manifold for SBC Marine use.
Note the bronze lined areas.




Also how would I check for the proper "volume" for the full dished pistons you mentioned?
As for the piston profile, you would need to actually look at the piston decks.

As for the cylinder heads, you should be able to determine the chamber volume by the casting number.

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trimta said:

Ok, thats the same manifold I have, Thank you for all your help.
Yes, if you have the bronze lined coolant runners, you can safely use it on a Raw Water Cooled Engine.

Soon as the weather lifts a little I'm going to lift the cover & get on top of that Engine to see if I can find those casting #s on those heads.
The Vortec cylinder head casting numbers will be underneath the valve covers.




THANKS AGAIN!
You are very welcome!

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