I have a guy that says he has a 69 DZ 302 but the only number he can find on the block is 3970010, is this a 302 casting number?? If so what else can I look for to ensure this is a 302, the guy only wants $500 so if this is a real one I am jumping all over it. Please Help!!!!! Thanks!

Yes, but dont get too excited. Chevrolet also made millions of 350 engines from that casting. You will need to find out what is stamped on the pad in front of the passenger side cylinder head.

What should be stamped on the pad if its a real 302??

It will be similar to V####DZ.

Make sure to check the casting date on the back of the block as well. That casting was used from 1969 through 1980.

Check the date the block was cast also. It can be found at the top rear of the block on the passenger side. Should end with a 9, although with a 0010 block I believe that could also be 1979. If you post a pic of the pad stamping it can be checked for originality by those that know on this board.
Hope it's original!!
Doug

Hello, If it is a real Z block the pad will be stamped VO112DZ V means plant, 01 means month, 12 means day, DZ means engine suffix (302) this is a sample stamp I made up for you to go by!, watch out because they is alot of restamps out there!!! I hope this helps you Good luck!! Jimi

If it is a complete engine look at the crank flange for the single notch.

Thanks a lot guys I appreciate it I'll let you all know what I find out. It is just the block $500 is a good price isnt it????

Not if it is cracked, rusty, 30 over, 2 bolt mains or high miles.

You could find a beater with a running 350 for $500.

Just talked to the guy he said the block is .02 over and has been line bored, is this DZ block worth $500??????

I would be wondering why it was line bored-spun main?

As pointed out there is nothing special about an '010' block-millions were made, a very few were built as 302 engines. A bare block has no special value and this one has had plenty of use. These days you have to question any engine stamping as it is easy to do. Even if it was a 302 by the time you acquire all of the other 302 specific parts you will have spent plenty. I regularly see 69 302 engines for sale. If I needed one I would look for as complete an engine as I could find.

If it sounds like I once bought a bare DZ block with a spun main it is because I did. Took a lot of favors and some talented people to straighten it out.

Check the date the block was cast also. It can be found at the top rear of the block on the passenger side. Should end with a 9, although with a 0010 block I believe that could also be 1979. If you post a pic of the pad stamping it can be checked for originality by those that know on this board.
Hope it's original!!
Doug
a 79 block would have the smaller ID pad on the passenger side

Just talked to the guy he said the block is .02 over and has been line bored, is this DZ block worth $500??????
yes, nearly all blocks have had this kind of machine work if they were going to be used for a rebuild

I'd be wary of a block that's been align-bored; align-HONING is quite common, but align-BORING is normally only done if a main has been spun or a main cap has been replaced.
:beers:

a 79 block would have the smaller ID pad on the passenger side

If it's a small pad 1-3/4" front pad and a seventies casting, it will also have the date casted into the side of the block and not along the rear flange like the earlier wide 4" pad blocks did. Pretty easy to spot both types. If it's a DZ block it might be worth 500.00 to someone requiring that date code, but is just another 010 block if you don't actually need one for a Z restoration. Be sure it's what you want before you go & drop 500.00 on it, and be sure it's a decent block as mentioned in the threads above.

Many of the earlier blocks will have an 010 / 020 number cast into the block behind the timing cover. This denotes a high nickel / high tin content in the casting and they are considered stronger blocks than many cast later in the series. If it is an early block, and it hasn't been align bored or decked more than once, grab it. Make sure you check the deck height and measure the bores and caps before you go jumping on it, and check to see if it's ever been sleeved.

first why do you want a 302 are you putting it in a 69 z it should be a date matching block because that will be where it will matter the most and it will have to be a 4bolt block so if it don't have the original dz stamp on it then think of it as being a 350 that could have been in any car or truck
if you just want to have a 302 then in your car then all you have to do is put together the the right parts
w and that's not an easy or cheep

That thread died six months ago....