Guest butlersZ Posted October 12, 2003 Share Posted October 12, 2003 Hey guys, This might seem like a really dumb question but what is meant by the different degrees of SBC heads (15, 18, 23 degree) ? I've heard different comments on them power wise. Is it the valve to cylinder angle or something? Quote Link to comment Share on other sites More sharing options...
Guest heinera Posted October 12, 2003 Share Posted October 12, 2003 those #'s refer to the angle of the valves in relation to the piston centerline. The 18 degree generally flow more than the 23, and the 15 more than that. But they are race pieces that require different intakes, and special lifters, rocker arms, and headers. Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted October 12, 2003 Share Posted October 12, 2003 lets look at the differances quickly your standard 23 degree cylinder heads , even better ones available, normally an intake flow numbers in the 270 -310 CFM range, Stock Chevrolet heads rarely surpassed 240 cfm, most of the 23 degree heads the stock components like rocker arms, push rods,etc. and you probably get away with the costs including the cylinder heads and rocker arms and push rods of under $1700-$1900 heres the 210 AFR flow numbers in the 12-18 degree heads normally cannot use any of the stock components, require special push rods, special rocker arms, and of course the different cylinder heads themselves,many if not most require offset roller lifter cams, special machine work,special headers,special pistons,and they are designed to work best only at high rpmd(above 5000rpm) and high valve lifts(above .600 lift) port size can run 235-290cc,cost of the complete setup , including the heads,cam,rockers,pushrods,intake,and special machine work seldom come in under $4500 and frequently much higher, but you do get the increased air flow that allows a 358-410 cid displacement to make 650hp- plus in a correctly set up engine, short answer, there great if you have very deep pockets, but they are not to be thought of as a standard or cheap upgrade http://www.brodix.com/onlinecatalog/page31-32/12X12-286CHARTSM.gif Quote Link to comment Share on other sites More sharing options...
Guest BigWhyteDude Posted October 13, 2003 Share Posted October 13, 2003 hey grumpy what kind of engineer were you? i have alot of respect for you for your insightful post here and the fact that you HAVE to be good in math to be an engineer. which i am not Quote Link to comment Share on other sites More sharing options...
Guest autocroos76 Posted October 13, 2003 Share Posted October 13, 2003 You can get the best of both worlds using Brodix-18 heads, they use standard 23 degree valvetrain. Only problem is that they are angle plug heads. This is a problem with a motor I'm building for my Corvette, the side exit headers must use straight plugs. On my 406 sbc I have Trick Flow 23 degree heads. Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted October 13, 2003 Share Posted October 13, 2003 hey grumpy what kind of engineer were you? TAKE YOUR PICK, they all fit OLD TIRED MECHANICAL ELECTRICAL MARRIED RETIRED GRUMPY MOSTLY UNDERFUNDED GROUCHY HAS BROKEN ANKLE EXPERIANCED HAS TWO KIDS 21 & 30 Quote Link to comment Share on other sites More sharing options...
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