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I have a 66 Chevelle that I purchased from someone who purchased it from someone who, well you get the idea. My question is this. I know that somewhere along the line the original motor was replaced with what I believe is a 350, but not really sure. I bought some supplies for a 1972 chevrolet 350 such as plugs, wires and the like, but the plug wire do not fit the distributor cap so I'm now wondering what I do have for a motor. Can someone give me an idea without pulling the heads and motor of how to identify what I have in the ole girl?
Really would appreciate it Also location on block will be helpful.

Can you post pictures of the engine? I am going to say that by your statement about the plug wires - it has an HEI distributor instead of a points type. The boots for the cap are different. Can you get a good look at the casting number on the block?

I was told that if I removed the alternator that I would possibly find a tag with numbers on it, but nothing was found. I did find out when my son in law looked at it that someone had taken out the points and replaced it with an early sytle HDI type setup so that explained the cap. I was able to get plug wire that will fit a 69 Nova but I'm still wanting to know the type and size engine and so forth.

You need to get a good look at the casting number on the driver's side of the block. It will be behind the driver's side cylinder head down on the flange that the transmission bolts up to. I have used small hand mirrors before to get a good look.

Thanks everyone. Will try and get a mirror down behind.