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ChadS
12-15-2004 06:59:02
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Re: Mr Buzzman72,,, in reply to Buzzman72, 12-15-2004 05:39:06
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Buzzman! Thanks again! The head I have is a straight valve head, Im not sure what it came off of. I was looking on oldihc.org, and found some very good info about the truck engines. Yeah, the pistons wont work from the tractor engines vs the trucks, I was thinking of a different desgin for the pistons for the truck head, and using heavier, tractor pistons, Im thinking it might help with torque. Here is what I came up with so far on the C-263 with a truck head. the tractor version, has higher domed pistons, but a really bad cyl head design, very restricted in the ports, due to the tilt valve head, and the compression chamber, due to the cyl head compression chamber casting change, they increased the depth of the chamber, to accomidate firecrater pistons. This caused the port design to be narrowed and more restricted in the ports. the compression chamber is deeper, so the room inthe ports were severly made smaller. The ports in the truck head, well its self explanitiory, way more flow vs a tractor head. you could not port, and polish a tractor head, to match the flow potential of the truck heads in stock form!! They even use the same diameter valve specs from the two heads,, Ive even used a truck valve in a tractor head, so I know they are the same, just different retainer clips,, but way stronger tension springs VS the tractors. Some times,, newer, is not exactly better in this case. Now, onto pistons,, Im goingto make a set of high compression, flat tops, and Im gonna make valve indentions in the tops. Using a 460 gas piston 3-9/16 bore onthe long stroke crank, and recut them to fit the chamber at .010 clearence below the block deck, im looking at 10 to 1 using the truck head. I dont think I wanna go much over 10 to 1,, its hard enough to feed it with a shebler updraft carb, 1.5 throat in the carb. but,, should be a good low rpm torque engine under 3000 rpm. Been thinking of using the 2bbl down draft intake i have for it,, but uh,, rules say not to,,, hahaha! I was figuring,, at 10 to 1,, 263 ci,, it would make 84 hp at 540, 1815 engine rpm, but the torque dont kick in until 2500 rpm, so it is not a hp engine,, its a torque engine, the faster it revs, the more it makes. limits are limits though, and im not gonna over rev it. at 3500 rpm,, it would make 155 hp,, but,, thats 3500 rpms though,,, not gonna rev it that hard. Im rebuilding the truck head, and was thinking I can mill about .100 off and be fine,, just have to keep an eye on the piston/ valve clearences. ChadS
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