302 cam ?'s
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302 cam ?'s
Ok, I've got a cam question for all you camshaft guru's. I'm building a mild 302 and want to figure out the best cam. It's a low mileage 72 shortbed truck, so the engine is only 8.2:1 compression. I'm installing some 1968 4barrel heads with a 53.2cc combustion chamber (factory is 58) so I think the compression will be around 8.8:1. I am using a Weiand dual plane intake and headers with 2.25" duals/ flowmasters. The heads have the factory press in studs, but if i have to I could have them machined for screw in studs. So what do you think? Duration? Lift? Basically I want the biggest thing that these engine specs will work well with.
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From: Ottawa, Ontario
Something wrong with your numbers. If the motor has stock pistons and it's a '72 302-2v the 58cc heads will give a 9.5:1 CR, and the 53cc heads will result in 10:1 CR. The cam you pick will be determined by the powerband you want, but generally with that much compression you can get away with longer duration... a 280 duration cam with at least 0.500" lift would be a good starting point I would think.
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Originally Posted by Conanski
Something wrong with your numbers. If the motor has stock pistons and it's a '72 302-2v the 58cc heads will give a 9.5:1 CR, and the 53cc heads will result in 10:1 CR. The cam you pick will be determined by the powerband you want, but generally with that much compression you can get away with longer duration... a 280 duration cam with at least 0.500" lift would be a good starting point I would think.
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Originally Posted by HemiEater
what do the pistons look like....and how far down the cylinders are they at TDC. Got any pics.....?
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just a little note not all books will give the same info.....compression HP etc.
what's the date code and casting number on the block....? it's up by the starter on the block
what's the date code and casting number on the block....? it's up by the starter on the block
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Originally Posted by HemiEater
just a little note not all books will give the same info.....compression HP etc.
what's the date code and casting number on the block....? it's up by the starter on the block
what's the date code and casting number on the block....? it's up by the starter on the block
In the mean time, it's such a mild build, I'm considering just keeping the stock cam and adding a set of 1.7 ratio rockers for a little more lift.
Any opinions on 1.7 ratio rockers? How much lift they will add?
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Originally Posted by HemiEater
well lets say you have .450 lift at the valve with 1.6 rockers.... we need to get the lobe lift so .450/1.60 = .28125
now X that by 1.7 so .28125 X 1.7= .478125 valve lift
now X that by 1.7 so .28125 X 1.7= .478125 valve lift
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Originally Posted by HemiEater
just a little note not all books will give the same info.....compression HP etc.
what's the date code and casting number on the block....? it's up by the starter on the block
what's the date code and casting number on the block....? it's up by the starter on the block
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Yeah, I've been looking in my book and at other sources and I can't find that as a block casting, only a head casting. I guess I'm gonna have to pull the starter down and brush that area clean with some degreaser.
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From: south louisiana
72 302 will have an 8 to 1 comp ratio. He's dead on with that. And the XE series comp cams do not work well with pressed in rocker studs, Comp recommends against this combo. The 54 cc heads will perk the ratio up to about what he's figured. If you want a cam that'll work with what you've got, go with the Comp 268H, it'll work with the studs, springs and comp ratio.