what year is my 350 chevy

[76 harley]

block number is 3970010,,head number on front passenger is a 2 ,,,under valve cover number are 3973487,,g281

 

[Chief-T]

Block is 67-80 and heads are 71-77. This is the same block I have and mine came from a '78 pick-up. You can further pin down the yr by the eng vin.

 

[Telman2]

3970010....302.....69....4...Z-28 Camaro
3970010....327.....69....2...Trucks and industrial
3970010....350...69-80...2 or 4
Very common block!!!

 

[76 harley]

would it be a 4 bolt main

 

[Golly]

Very good chance if it came out of a truck. You have to pull the pan off to find out for sure.
If it's a genuine Z28/302 block , the engine # stamped on the block will tell you, sell it to a restorer and buy your self a complete motor! Those things would fetch good money I reckon.

 

[donsrods]

I have that same block sitting in my shop and it is a four bolt main, but some were two bolt. Only way to know is pull the pan.

Don

 

[blyndgesser]

Very good chance if it came out of a truck. You have to pull the pan off to find out for sure.
If it's a genuine Z28/302 block , the engine # stamped on the block will tell you, sell it to a restorer and buy your self a complete motor! Those things would fetch good money I reckon.

The only Z28 block that is special enough to fetch good money would be a 302. The OP says it's a 350, so I'd say rebuild it if it needs it, and just use it.

 

[Mike]

3970010....302.....69....4...Z-28 Camaro
3970010....327.....69....2...Trucks and industrial
3970010....350...69-80...2 or 4
Very common block!!!

3970010 simply signifies a large journal, 4.000" bore casting and nothing else.

The actual bottom line is a 3970010 block is a 3970010 block is a 3970010 block, but if you really need to know the year the engine was assembled, look at the block deck surface, just in front of the right (passenger side) cylinder head. Unless the block has been decked at some point in it's life, the production code will be stamped there. If the number is gone, then you can get a set of stamps and make that block any year you want, same as the resto guys.

There is no way to know if it is a 4-bolt block or not, short of knocking off the pan, as others have pointed out. Unless you are planning on running a blower with a lot of boost, a 2-bolt block will work just fine for what you are doing.

The head castings are a 75CC chamber head of a 1968 - 1973 vintage. And no, with just the casting number, there is no way to know the valve combination. That head was used a lot with the 1.940/1.500 valves. And that casting even found its way onto the LT1 in 1971, with the 2.020/1.600 valve combination.

The good news is that they are 'heavy' castings, which means they are less crack-prone. The bad news is that unless the engine has been sitting in a time warp, it's likely seen its share of rebuilds and valve jobs. Which means the valves are sunk most of the way to China and the block has likely been bored at least once. So proceed with caution, if this is something you are looking to buy. The heads are old enough they are likely going to need the full enchilada to bring them back to snuff. Seats, guides, valves, etc. And you don't want to spend a bunch of money on a block that has already been bored, particularly if you're planning to build some power with it.