New cam versus rockers
02-26-2002, 10:31 PM
#1
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Location: Brookfield, WI, USA
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New cam versus rockers
Current have an '85 with AFR190 heads, AS&M runners, ported plenum, ported edelbrock intake, no headers, cold air.
The cam is small;
valvetiming OPEN CLOSE
at .006 INT 20 BTDC 60 ABDC
EXH 72 BBDC 16 ATDC
duration at 0.50 212 218
lobe lift 0.2960 0.2960
lobe separation 114
This a a flat hydraulic tapet cam. Purchased this small cam for two reasons; need to pass stringent pollution testing on a dyno
and didn't want my kid to kill himself. Well, he now can handle the power, and wants more. With the current 1.52 rockers, that
gives a lift of 0.449. If we went to 1.60 rockers, give a lift of 0.474. With 1.70 rockers, thats a 0.503 lift. The obvious advantage
of the rocker approach is less cost, less work, and no need to go with roller lifters for a reasonably high lift. What's the down side?
Am I better off going with a bigger cam, and if so, at what point do you need to use roller lifters? Are there any problems switching
over to roller lifters on an '85? Does anyone know approximate horsepower difference with the alternative? Any advise is appreciated.
The cam is small;
valvetiming OPEN CLOSE
at .006 INT 20 BTDC 60 ABDC
EXH 72 BBDC 16 ATDC
duration at 0.50 212 218
lobe lift 0.2960 0.2960
lobe separation 114
This a a flat hydraulic tapet cam. Purchased this small cam for two reasons; need to pass stringent pollution testing on a dyno
and didn't want my kid to kill himself. Well, he now can handle the power, and wants more. With the current 1.52 rockers, that
gives a lift of 0.449. If we went to 1.60 rockers, give a lift of 0.474. With 1.70 rockers, thats a 0.503 lift. The obvious advantage
of the rocker approach is less cost, less work, and no need to go with roller lifters for a reasonably high lift. What's the down side?
Am I better off going with a bigger cam, and if so, at what point do you need to use roller lifters? Are there any problems switching
over to roller lifters on an '85? Does anyone know approximate horsepower difference with the alternative? Any advise is appreciated.
02-26-2002, 11:08 PM
#2
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Re: New cam versus rockers (C5Don)
I would do the RR right now, a cam will require tuning and the installation.