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#2
06-30-2007, 12:20 PM
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Re: L78 tune up
Back in'66 I think GM was calling for .020 intake and .024 exhaust. By '70 they were calling for .024 and .028. Looser gives more bottom end torque. I run .022 intake and .024 exhaust with the stock cam. Our 427 ran almost 200K miles that way and our L78 about 30K since we bought it. Seems to work for us.
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Chevelleless after 46 years......but we did find a low mileage, six speed, silver 2005 Corvette. It will just have to do for now. 
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#3
06-30-2007, 05:47 PM
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Re: L78 tune up
What cam was put in it when it was rebuilt? The cam card will tell what lash the manufacturer intended...our Crane/GM cam calls for 24/28, but someone told me the cam card on the same cam *now* calls for like 24/26?
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#5
06-30-2007, 09:38 PM
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Re: L78 tune up
Still stock, as in rebuilt to stock specs, or as in it's an untouched short block from back in the day with original guts? If so, 24/28 is where you'll wanna be...a little tighter is "ok", but *do not* go any looser...
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#8
07-01-2007, 03:32 AM
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Re: L78 tune up
Thereabouts...if you get too tight, the thing won't wanna rev and you're putting too much stress on the valvetrain...but conversely, too loose and you'll hammer your lifters to pieces. From .022-.028 is probably the safe zone assuming it's an older stock cam...I've seen a newer replacement cam with 16/16 figure, and then of course some of the newer tight lash cams take that a step further.
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#9
07-01-2007, 05:50 AM
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Re: L78 tune up
[ QUOTE ]
From .022-.028 is probably the safe zone assuming it's an older stock cam... [/ QUOTE ] Is that setting them hot or cold?
__________________
Craig S. "I saw Elvis At 1000 Feet" John Force.
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