Block casting numbers

Right then. I'm about to rebuild a 3-main 1800 but the engine has been "worked over" before. Out of curiosity, can anyone tell me if the casting numbers on the block have any relevance to the eventual engine designation? Mine is marked (amongst other things) "12H750" I am under the impression that this was a part number for the block itself and had nothing to do with the eventual engine designation/numbering other than it probably ended up an 18G or GA.

Mike,It's not engraved in stone, but I believe your engine block is for a 1963 to 1967 "B". OEM part #48G318. Supposedly the last casting number in that series was, 12H906. Engine numbers as 18G/18GA/&/18GB. From 68 to 71, the casting numbers end at 12H2389. OEM part # 48G538. Engines 18GF/18GH/and 18GK. From 72 to 74 1/2, casting numbers end at 12H2923. OEM part #48G644. Engines 18V584/18V585/18V672/18V673. I hope this little bit of info. helps. /ubbthreads/images/graemlins/tongue.gif PJ "EDIT" Mike I'm sorry as I gave you the part numbers for the heads for those engines. Will try to get the block numbers for you. PJ

Thanks, seems all I can find is head casting numbers too! It is not perhaps a big deal but I get curious, ya know?

Mike, You said your engine is a three main 1800. I'm not real sure, but I think 5 main 1800s came out in 65. If that's the case, then your engine is probably a 63 or 64. Don't you just love a good mystery?? /ubbthreads/images/graemlins/yesnod.gif PJ

I've mentioned this in another forum but also a chance to mention it here. The block on my 79 and 80 MGBs look very similar but there are also some differences such as the distance between the spark plugs and the head. The hubby thinks this is very odd since one was build in Feb 79 and the other in Feb 80 and more so because they were at the end of production. Maybe that's the answer--at that time they were just tossing anything into them /ubbthreads/images/graemlins/smile.gif

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The block on my 79 and 80 MGBs look very similar but there are also some differences such as the distance between the spark plugs and the head.

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Hehehe... an all my cars, the distance between the plugs and the head is the same....



...Zero.



...But maybe that's because the plugs actually thread into the head and are torqued to slightly more than hand-tight. /ubbthreads/images/graemlins/jester.gif

Tis true Kenny but I didn't say it just right did I? The hubby noticed it last week when the trouble started with the distributor. He just picked up a cresent wrench (I know, the wrong tool) and removed the #1 spark plug on the 79 to see if it was firing. Later in the day he said "think I'll check one of the plugs on the 80 to see if the weber is adjusted right". He picked up the same cresent wrench and there is no way possible the plug can be removed with it because it is to close to the end of the block and more recessed. That's when we began looking at the other differences and the 79 head is slightly longer with a very minor shape and the distance between the plugs is different. Did I do any better explaining /ubbthreads/images/graemlins/smile.gif

OE= Original Equipment as it came from the factory

OEM= Original Equipment manufacturer - replacement parts for the original equipment, and could be the same company or a seperate company using the same molds or plans and is approved by the Car company that sources the parts.