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Old 09-27-2010, 07:40 PM
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Cam choice?

I was wondering what you fellas thought about what cam to use for my 72 K20?

355
KB 12cc dish pistons(193)
.015 in the hole
882 heads(I know, its what I have to work with)
Victor head gasket with .026 thickness and 4.1 diameter
Hei
Edelbrock Performer
Q-jet
Hedman long tube headers
4 speed
4.10 with 285/75-16

I was looking at the smallest of the Voodoo line or the summit 1102 because I am not sure the Voodoo is worth the extra money for the current set up. Any other suggestions? Thanks in advance.
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Old 09-27-2010, 09:37 PM
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You can take a look at this link for calcs on compression ratio.

http://www.kb-silvolite.com/calc.php?action=comp

It is useful in determining what the cam has to work with. Your set up is about 8.5:1 static CR if using 76 cc for the 882's is that what they are? have you measured/cc'd them?

Look for specs on the cam namely the intake closing point, plug these into the calculator using the 5.7 rod length of the 350. You may want to consider going with the earlier closing cam to help build up some cylinder pressure as you are down there on compression.

the voodo, is that the 60100? its at 207/213 dur @ 0.050 and .437/.454 lift on a 112 LSA advertised at 250/256 dur

The 1102 is at 204/214 @ 0.050 and .420/.442 on a 112 LSA adv 262/272 dur

IMHO either cam would not be a mistake in this case at 8.5 DCR and running the setup you have.

The voodo is listed at a wider rpm range from 1000-5000, the 1102 is 1200 -4800. The voodo may require closer attention to the valve springs, those cams have an aggressive ramp rate, but it would be my choice if cost was not an issue.

2 more of my cents
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Old 09-27-2010, 10:56 PM
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I get 8.52:1 SCR, so you're right on the money Custom10.
Schatzy, I don't recommend flat tappet camshafts any more due to the high number of failures in the past few years. But I think you are right on the money with the cam timing you're looking at for the SCR of the motor. I would be very careful though, in the choice of cam and lifters from one manufacturer. There are still some of those "white box" lifters floating around in the marketplace. I'm not saying that Summit or anyone else would intentionally supply you with offshore lifters, but I would be very careful to source the lifters along with the cam in one package direct from a known cam grinder. This is just my opinion based on inferior lifters showing up in the marketplace. Also, take some of the grinder's claims of power range with a grain of salt. Any cam you stuff in the motor only has a 3500 rpm range of power. Some of these guys will try to tell you that the cam makes power from idle to 5500.

Here, for instance, is a cam and lifter set from Crane that comes as a package from the factory if you order direct from the factory and not from a middleman supplier who can change lifters and not tell you. Again, I'm not accusing anyone of anything. I'm just saying that additional profit is a powerful incentive.
See the 100032 cam and kit here....This is what I would use in your motor....
http://cranecams.com/pdf/_catalogs/m...010-54-107.pdf
You'll want to afford yourself every advantage that you can in order to insure long life from the flat tappet cam and lifters, so please read through this list and take advantage of these suggestions....
http://www.crankshaftcoalition.com/w...ips_and_tricks
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Old 09-28-2010, 07:00 AM
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Thanks for the replies. I know its only going to have 8.5 compression that is why I am staying conservative on the cam. I thought about going with a roller since I have a cam and lifter set on the shelf but the cam is way to big, so I have considered going with a smaller roller but the heads have the "Z28" style springs and this is just going to be a motor to throw in the truck for now because the 383 that I had someone build has a nasty vibration from 2000 rpm on. I plan on changing to an automatic when the funds and time allows and probably change to a different engine combo then.
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