I have a 350 sbc in my 1989 camaro and im trying to figure out what year the block is and the casting number on the back drivers side starts with 57L6 then like next to it it has three more numbers 56 and i cant make out the third but ive tried searching the first four to get a general idea but nothing comes up in the searches. any ideas or suggestions?
trying to find the year to start looking for possibly a new crank because of a knocking sound in the bottom end

 

Cam wouldn't give you a knocking sound in the bottom end. Its not part of the bottom end.

Bottom end noise could be main crank bearings, or more likely rod bearings. Usually do to inadequacy in the oil and oil supply.

 

lol i was definally thinking crank but for some reason i typed cam sorry bout that ill change it

 

I think you need more numbers. There should be 6 or 7 digit number on the block - then search Google for SBC casting numbers and you'll find many sites with info. For example, my 350 has 3970010 on it.

 

If I remember correctly, on the passenger side front of the block next to the cylinder head are some numbers stamped on a pad that should tell to the actual "birthday" of your engine. Sometimes they get milled off when the engine gets rebuilt tho. Hope this helps.

 

There is no block casting number that I know of that starts with a 5. It's more than likely going to start with a 3. If not, a 1. There's a few that start with a 4, and one that starts with a 6.

Pull the valve covers off and find the head casting numbers, they're easier to find. That'll give you a general idea of what year the block is from if the heads are original.

For example, I have 462624 heads and a 3970010 block. 462624 heads were made from 1976 to 1987. 3970010 blocks were made from 1968 to 1979. That tells me that if the heads are original to the block, it only could have been made sometime between 1976 and 1979. I also have a 3932442 crankshaft, made from 1969 to 1985, but that doesn't narrow it down anymore than the heads and block already do.

Good luck with figuring it out. I was very curious about figuring out what I have. Finally pulled it, pulled the oil pan off, and discovered it's a 4 bolt block. So, I may build a 383 in the near future.

 

Thanks guys i did see the numbers on the passenger side like next to the watter pump but i could only make out like 1243 at the end i think. and i saw a similar post just like mine but it had no answer to my problem.

here is the other post maybe someone can look at this one and get an idea

https://www.thirdgen.org/forums/tech...ers-block.html

btw the heads are not original to the 350 i have because they are vortec and i was told the 350 was taken from a 90's suburban but who knows. im just trying to find a general year in case i have to get a new crank

 

Bad cam bearings will give low oil pressure especially when the oil gets hot. Bad main bearings will give low oil pressure until they get bad enough to seize the crank. Neither should give a knocking sound.

Knocking is usually rod related. Normally rod bearings, loose caps etc. Depending on the sound, it could also be a wrist pin.

Guy at work had a knocking sound in his 4.0L jeep. About 4 weeks later, it spit a rod out the side of his block.

 

Your engine will say 5.7LG for a 350 (5.0LG for a 305...)




Your block casting number is next to the Dist.




Your number pad is on the front passenger side of the block.