Need help decoding block
 

Looking to ID the engine we pulled out of one of my Grandads GM trucks.
was a 69 flat bed dually truck

casting # ML 24800

Re: Need help decoding block
 

3970010 https://www.mortec.com/castnum.htm

Not sure how to decode ML24800, but some do.

Re: Need help decoding block
 

thnx

Re: Need help decoding block
 

so.. from that

3970010....327.....69....2...Trucks and industrial
small or large journal?

Re: Need help decoding block
 

3970010 is the most common SBC from the very late 60's to 1979, and 99.9% are 350's

Re: Need help decoding block
 

This link below has ML .


ML 1967 327 air cond. 275 4 F X
ML 1968 327 s h/p 325 4 Chevy II

Link:http://www.gregwapling.com/hotrod/mo...rs-hr-tbs.html

Most of the time the first letter is Plant.
From this link:https://nastyz28.com/sbchevy/sblock.html

Code Engine Plant Code Engine Plant
F= Flint (Motor) S= Saginaw Service
H= Hydramatic T= Tonawanda
K= St. Catherines, Ontario(McKinnon Industries Canada) V= Flint (Engine)

M= GM of Mexico









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Re: Need help decoding block
 

Warren is correct almost all 10 blocks are 350 ci

To inspect further you will need to pull the oil pan and see what crank number you have to fully id weather 350 or truck 327

Its a large journal block

Re: Need help decoding block
 

pulling pan.. :-D

Re: Need help decoding block
 

Made in mexico block is surely a goodwrench motor from the 70's

Re: Need help decoding block
 

Check for the original paint on the block, but best bet is an older (probably 80’s vintage?) GM Targetmaster replacement block/engine. That is a generic casting number that will only you basic idea of engine. It was used for early 327’s and 350’s starting in 69(?) on up to the late 70’s in passenger cars. It also the reason the head pad has a weird stamped number. Normally they would read as a series of letters and number like listed in the nastyz28 site. To the left of the number would be partial VIN for the vehicle it was installed in if a factory installed engine. The alpha-numerical sequence where yours starts with an “m” would tell you the engine foundry/assembly plant, what plant it was installed into a vehicle at. That most definitely is not an original engine from the factory. Probably a crate or GM dealer, non-warranty replacement.

Side note though, if you find and engine you have an issue decoding, email the casting and head pad stamping numbers to the GM Heritage Center. It will take a few weeks, but they will email you back to confirm year/make/model, engine specs and where assembled/installed. I have done it for a couple of engines now and they are more than happy to help you out.

Re: Need help decoding block
 

This casting number was common in trucks 69 to 79 was the last year they used this casting number

Re: Need help decoding block
 

It's all about the stamped #, not the embossed casting #. But usually it's the suffix code. This is a prefix code. Does that mean it's a Mexican block?

Re: Need help decoding block
 

Except in this case for the casting (and most GM crate motors now) that have Made In Mexico cast above the normal casting number on the back. In that case its more about the casting out of the gate as that, as far as I have seen, where that cast into the block will tell you the it was never a factory installed block and most likely not a warranty block/engine.

Re: Need help decoding block
 

I guess prefix means replacement block. Now I see the Made In Mexico embossed above the casting number. So in this case we can somehow identify the block by the casting number? Or is it since it is a replacement block it can't be identified as from any particular model?

Re: Need help decoding block
 

Special-K what I found in lots of downtime reading at work this summer, is those Made In Mexico blocks with the stamping in the head pad that begins with an “M” are untraceable as far as what they went in. They have no partial VIN nor the engine plant / vehicle assembly plant stampings. It is more of a serial number than anything with no VIN. Again that is just what I discovered researching engine stamping/castings. I’ll try and shoot the GM Heritage Center an email just to pick their brains.

Re: Need help decoding block
 

Good info so far. Thanks

Re: Need help decoding block
 

The 010 block first year is 1969. It is always a large journal crankshaft, so 327 and 302 (Z28) in 69 and 350 69-80. Pre-68 327s were small journal cranks and 68 327s/302s used a different block casting. 010 blocks can be either 2 or 4 bolt mains. Pretty sure none of the 69 302 or 327 blocks were cast in Mexico.

More than likely a 350 Targetmaster over the counter engine.