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  #16 (permalink)  
Old 01-13-2012, 04:11 PM
chevy302builder18's Avatar
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Quote:
Originally Posted by DoubleVision
This is the retro fit cam, however, they also have this same cam for OEM roller cam blocks which is what he`s running.
http://www.summitracing.com/parts/CCA-12-420-8/
His combo consists of RHS Vortec heads. With this cam and combo, it has absolutely killer out of the hole torque with 3.42 gears and gets good fuel economy.
well this looks part way what im gonna be running, 406, large port vortecs, 10 to 1 CR. Only difference is displacement and the runner size thanks for sharing. I havent looked at this in a mean while, and now its already got me thinking bout this same retrofit cam. Looks like id have a killer torque spec too huh?

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  #17 (permalink)  
Old 01-14-2012, 12:15 PM
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Quote:
Originally Posted by chevy302builder18
well this looks part way what im gonna be running, 406, large port vortecs, 10 to 1 CR. Only difference is displacement and the runner size thanks for sharing. I havent looked at this in a mean while, and now its already got me thinking bout this same retrofit cam. Looks like id have a killer torque spec too huh?
I don't know where the DCR would be w/that cam in your engine w/10:1 CR. I think it'll prolly be OK w/premium but I'd be checking to see that it's OK for pump gas. I'd also not want to try to go much smaller on the duration @ 0.050" lift.
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Old 01-14-2012, 02:30 PM
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Quote:
Originally Posted by cobalt327
I don't know where the DCR would be w/that cam in your engine w/10:1 CR. I think it'll prolly be OK w/premium but I'd be checking to see that it's OK for pump gas. I'd also not want to try to go much smaller on the duration @ 0.050" lift.
CompCams 12-420-8 closes the intake at 33.5 degrees ABDC @0.050" tappet lift. KB's DCR calculator puts the DCR at 8.90:1 with 3.750" stroke and 5.700" rod. Using a 6.00" rod puts it at 8.88:1. I suppose you could run premium pump gas if you ran a very tight squish and smoothed everything out in the chamber and piston crown, but as for myself, I would rather use a little more cam and tame down the squeeze a little. With 10.00:1 SCR and a 5.700" rod, a cam that closes the intake at 42 degrees ABDC @0.050" tappet lift would yield a DCR of 8.48:1 and that's probably what I'd do because a DCR of around 8.5 seems just about right to me. I never did like to build anything right up against the wall with no wiggle room. Something like this is what I'd be lookin' at....See the intake close at the bottom of the card....
http://www.cranecams.com/product/car...detail&p=24188
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Old 01-15-2012, 03:51 AM
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I wasn't sure on the DCR but I'm 100% w/you on not building an engine w/CR right on the edge- there's possibly a few percent gain in power per point of CR, but a bit too much CR can cost huge power if the total timing has to be retarded from best power timing. Or can cost huge $$$ if detonation is allowed to occur under load. Plus who knows what the future holds as far as available gasoline octane goes.

Much better IMO to build in some leeway in the CR for a bad tank of fuel, a parts failure that runs the coolant temp up, etc.
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Old 01-17-2012, 01:45 AM
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id probably wanna run a lil bit bigger Gasket, if the qeunch is good, and the cam you listed, is a super charger cam i didnt think i could use one in a natural aspirated, but i geuss anything can be done with the right stuff. Hmm if i were to step up a lil i might run the 10:1.1 SCR and a lil bigger at .050 it just might be what im looking for? I was also looking at Howards Max Torque retro fit cam kit(i think its a kit),
110325-10
and lunatis bare bones cam set, Dont know the camshaft itself, just the kit (im gonna take a good look at it specificly)
10020LK
im a big newb at camshafts, i dont like and wont like for a while, cause all of em have a catch. and im not really a huge fan of checking em out
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