ok just got a 350 block for my 86 trans am gonna turn it into a 383 and would like to know the exact year or what ever good info you can gather for me? Ok down to buisness this is GM right by it was the #38 the ID for this was 3970010 any thoughts? their was on the oil filter housing a 010 020 166 I was told 010for tin and 020 for nickle the 166? a blend?

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it's either a 305, 327, or a 350 - have to get crank numbers and/or count main bearing cap bolts to be sure

it's a 350 4 bolt just wanted to know why both 010 and 020 with a 166 are above the oil filter? I know they are for both metals byt ive heard either 101 or 020 not both with the 166?

Then you checked the crank etc. I assume - cause both the 302 and and the 350 have 4 bolts in that block. I was always confused on the 010, 020, etc stuff myself - always got conflicting replies - I gave up and I figure who cares - like everything else it's gonna blow when it blows - drive it like ya stole it!

no it is def. a 350 block
Im gonna def drive like I stole it for crack
thats why it's gonna be my 383 blowin rubber down the whole stretch

and ya the numbers are confussing but would be nice to know the meterials it;s made out of that's all?

It's made out of cast iron. You'll never know the exact metallurgy of the block by numbers on the block. Just about all 010 castings have the 010 and 020. 010 usually means 1% nickle and 020 usually means 2% tin but that doesn't mean the block was cast with that metal mix so the numbers are meaningless.

There are numbers and casting information all over the block and the majority of them can be deciphered. The 010 block casting number is the easiest as it indicates a 4" bore block. Since it was used for a 302, 327 and 250 engines, the only thing that makes them different is the crank stroke.

The suffix number on the pad in front of the passenger side head can give a lot more information about the original vehicle and the VIN number near the suffix number will match the last part of the VIN on the original vehicle.

Other than the suffix number, the only other information in block castings that means anything are build date codes.

If you want a strong block, throw away that factory casting and buy an aftermarket (non chinese) block.