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#2
05-21-2009, 06:03 PM
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Re: 143 Blueprint Cam Install
Valve springs are originals but were checked .Timing is at 36 total,jetting is 70 primary and stock secondarys on a 4557 carb.The engine has 15,000 miles not rebuilt .My next move will be to set it at TDC and check the mark on the balancer to see if it has moved .I get no spark knock with pump premium and 11:1 comp .
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"Knowledge is good" Emil Fabor 67 L/78 Camaro SS/RS H-H,1W,2LGSR,3SL,4K,5BY. (Sold) 70 L/78 Nova M-21,Black Cherry,Sandalwood Int. 09 Pontiac G8 GT Premium,Sport,Roof. Liquid Red. 
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#3
05-21-2009, 06:30 PM
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Re: 143 Blueprint Cam Install
If you plan on running this car, get rid of those stock valve springs. They either (A) broke and dropped a valve, or (B) couldn't keep up with the cam allowing the valve to free fall shut at high rpm. This eventually pounded the keepers through the retainer allowing a dropped valve again. These are the main reasons that there aren't too many original L78s and L72 out there. We didn't seem to have any problem with the L88 springs in the old days.
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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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#4
05-21-2009, 07:28 PM
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Re: 143 Blueprint Cam Install
That was true to a point.
For 1970 model production,Chevrolet used a more dureable BB valve spring that avoided dropped valves @ higher RPM. During 1968-9,they started to see an increase in BB warranty claims filed do to unreliable valve springs,so they used the stronger #3970627 to replace the weaker #3859911 spring. L-88's were exclusive to the #3916164 spring.
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#5
05-21-2009, 09:24 PM
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Re: 143 Blueprint Cam Install
What springs do you guy's recommend ?I baby this thing but would like to twist it up if needed .
__________________
"Knowledge is good" Emil Fabor 67 L/78 Camaro SS/RS H-H,1W,2LGSR,3SL,4K,5BY. (Sold) 70 L/78 Nova M-21,Black Cherry,Sandalwood Int. 09 Pontiac G8 GT Premium,Sport,Roof. Liquid Red.
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#6
05-21-2009, 10:20 PM
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Re: 143 Blueprint Cam Install
[ QUOTE ]
What springs do you guy's recommend ?I baby this thing but would like to twist it up if needed . [/ QUOTE ] Any modern made spring should be fine...they won't have to be anything special for a "stock" cam, so just call Comp/Isky/Bullet/whomever and they'll be able to fix you up. IIRC, in our L72s we're running the springs that came with the Gm/Crane blueprint cam on one engine, and a set of Comps in another...
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