Discussion in 'Small Block Tech' started by 72 skylark custom, Jan 11, 2020.
Where would the casting numbers be on a buick 350 to check with the vin number?
It’s hard to see the vin number but it’s stamped on the front of the block drivers side.
Okay thank you i will look this morning
I dont think i found it... i cant see any numbers on that side of the engine, here a pic of what im looking at
It’s tough to tell from the picture, but is part of the number visible right above the timing cover?
My '71 block is stamped vertically (front driver side, block inverted on engine stand in picture).
Are you trying to find out if it’s a numbers matching engine? Or do you just want info about the engine? To find out the HP rating and compression ratio look fir the two digit code between cylinders 1 and 3 on the block deck ledge.
It'll be right here:
Numbers matching engine part
This is because i was told the car is numbers matching, but on the cylinder heads i see a 73 on each head lol
Could it be behind the timing cover lime right where the gasket is?
Nope. It should be on the drivers side on the smooth part of the block.
72 engines had 73 on the heads
Okay once the motor gets pulled in the next week ill get the paint cleaned off and hopefully it will be a little easier to see.
why did they do this does anyone know, because that would seem very misleading
There were improvements made to the castings over the years so part way through 72 they started using the later style heads. Most of the changes made were to reduce cracking issues that the early heads had.
Thats very interesting. I had no idea they did that. Thats pretty cool
Extra coolant passages were added. They are in the Center of the heads. If the later heads are used on the early blocks then coolant will leak into the crank case. The later blocks have extra deck surface to support the gasket at the extra coolant port location. It’s a dead end port.
Thats something i never wouldve thought of, when i pull the engine out before the car goes away. Ill pull the heads and look at those passages to see them, i wonder why the earlier heads were susceptible to cracking? Just from the lack of cooling passages?
Yes that’s why they were cracking. Interestingly though the cracking although very common rarely actually caused a failure. I learned this from Greg Gessler the porting guy. He would check them for cracks (magniflux) before he spent $$$$ on them. He said he brazed or welded them up, I can’t remember which.
Then I started looking at the heads over the years and I’ve seen a lot of 68-72 heads that are cracked.
Thats pretty cool. Im suprised the cracking wouldnt cause some sort of failure like you said. It must just be where the crack is and how bad it is