think you would be way better off with the EVO head from EC CARBS . head is on sale right now for $299 and you need to buy the springs,retainers,keepers separate and that will be another $50. this head will out flow that go power head all day and might be one of best casted heads on the market before you get into the billet heads..
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with a .045 fiber style/steel fire ring you would be at 11.42 and a .032 copper 12.08
what every you do, don't try milling you head with a block of sandpaper...etc only the correct way with milling machine...etc. head needs to be flat or your done...lol make sure you buy a stud kit. stock heads bolts can sometimes stretch after time and after reusing them. if you decide to o-ring the head with the steel wire? then use the .032 copper head gasket with it annealed and with a very..very light coat of toyota sealer (103)
I'm going to just go with the .045 fiber/steel ring gasket. the engine will get torn down after 6 full racings. mainly to check the head/springs valves..etc and then get a new head gasket. only running gas and we only can get 110 octane so my friend will need to mix a small amount of ethanol free 91 to being the octane down so it burns more efficient with only 11.42 compression. my engine i run 13.1 + with 110 and runs like a dream...lol
HERE IS MORE INFO ON THE EVO HEAD look at the bottom page for compression.
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here is what a .045 fiber steel gasket looks like. when using this type of gasket i spray a light coat on both sides with a copper spray.
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back to springs and the EVO head. the head is setup for .850 spring height. so be careful what springs you buy and install. just so much that goes into this motor to make real power and it can be real easy F-things up very quick. .310 dyno cam you were talking about with a 28mm mikuni carb. i would start with a 21 pilot and a 330 main and go up from there on main jet sizes. really don't like this tilly block with a 3inch bore with the kind of racing we do. block is at its max and is ready come unglued. i use a different block 10x times stronger top secret ...lol none of the top performance engine companys won't touch it because nothing will bolt up to it without mod's done to it (machine work) easy for me.
BIG BORE small block 290cc maybe i will get it done someday... lol top head bolts are way out.
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