WTB/WTT 65-69 NOS Cylinder Unit

[cnicol]

I purchased a set of 65-9 NOS piston cylinder units and found one was a '64... oops!

So, I'm looking to buy one NOS 65-9 piston/cylinder unit P/N 3869276. If possible, I'd like to trade or sell my NOS '64 piston/cylinder unit P/N 3847243 for the '65-9 unit I need.

[azdave]

From what I've heard, that's not uncommon as the dealers supposedly sold them that way and considered them a proper set as long as the opposing pistons were of similar mass. I also bought a full set of six a few years back and one of mine is a 64 type too. I plan to use mine with a spacer ring (section of a stainless hose clamp) around the top as I've seen mentioned in old tech topics.

What do the expert engine rebuilders say about that these days?

[cnicol]

I sold parts at a Chevy dealer in the early 70s and we always sold the correct cylinders for the application.

At that time some 65-9 cylinders had the correct, wide cast-iron head gasket sealing surface and some were 64 narrow-style with a factory installed, very tight, machined ring around the top of the cylinder. In combination with the machined sleeve, the 64 cylinder had the correct, wide gasket-sealing surface.

I think this was done to consolidate production to a single '64 style casting. Sold without ring for '64s and with the tight, machined ring for '65-9 with their wider head gaskets. I have some of both here in my shop.

I heard of guys using tin-can material and large radiator hose clamp bands to center 64 barrels in the larger 65-9 heads but I've never tried that myself and would not recommend it except for "emergencies".