Was planning on bolting the head on my 261 today. Lined the head gasket up to the block and noticed that a few water jacket holes aren't the same diameter. Got the gasket in a kit from Best Gasket, the gasket number is 639. Seems to me the small hole diameter would restrict water flow and cause erosion of the gasket. I attached some pictures that should show what I'm talking about.
On another note, were these engines supposed to have alignment dowels for the head?
Any thoughts? Have some spare time here with the virus pandemic, good chance to get some stuff done.
Some gaskets are designed that way to allow the coolant to spray from the block into into the cylinder head at a higher velocity for better cooling of the head. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Thanks for the answers fellas. What's everyones thoughts on using gasket sealant on these head gaskets? Seems like some people use sealant and some don't.
1953 Chevrolet 3100 261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done In the DITY Gallery Video of the 261 running
1964 GMC 1000 305 Big Block V6, sm420, the next cab off restoration
The only head gaskets I use sealer on are the .023" thick steel shim type we used on high performance Chevy V8 engines, the ones made of a single piece of embossed sheet metal. Those gaskets benefit from a brush-on non hardening sealer like Permatex Super 300. The sealer is there to prevent seep coolant leaks, not to assist in sealing compression or combustion gases. I don't think I've ever seen that type of gasket made for a stovebolt six. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I use the copper spray on all of my head gasket installs. I can’t really say if it helps or not. I had an old time mechanic teach me to use the stuff when I was a teenager (many many moons ago now) and so I always have. One thing I can say is that I have never had a head gasket failure and I have quite a few of these motors under my belt, stock and modified.
