Reply to "Solid Flat Tappet Street Cam"

No comments eh? No interest in solid flat tappet cams?

Was the last one too hot for you guys? I once penned a Boss 351 replica cam … a milder camshaft than the last one.

For reference the factory Boss 351 solid tappet cam had the following specs:

Duration at 0.020 inch tappet lift (advertised) = 290°/290°
Duration at 0.050 inch tappet lift = 230°/230°
Gross valve lift at 1.73:1 rocker arm ratio = 0.502/0.502
Net valve lift at 0.025/0.025 lash = 0.477/0.477
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ICL = 111° ATDC --------(An earlier ICL synchronizes air flow capability more closely with air flow demand and makes more power.)
LSA = 116° --------------(A wider LSA reduces overlap, produces a wider and flatter torque curve; improves controllability.)
Seated Overlap = 58° ---(Limiting overlap to 60° or less improves vacuum, idle, low rpm torque and drivability.)
Seated EVO = 86° BBDC (An earlier EVO compensates for a muffled exhaust, improves idle, extends high rpm power, and reduces pumping losses.)
Seated IVO = 34° BTDC (Limiting the IVO to 30° or less improves vacuum, idle, low rpm torque and drivability.)
Seated IVC = 76° ABDC (A later IVC lowers the DCR, requires a higher SCR; can lead to reversion at idle.)

Horsepower was 370 peaking at 5800 rpm. The cam I penned provided 35 more horsepower (405 bhp peaking at 6100 rpm) AND improved drivability at the same time due to the modern lobes. Here’s the spec:

Duration at 0.020 inch tappet lift (advertised) = 278°/278°
Duration at 0.050 inch tappet lift = 230°/230°
Gross valve lift at 1.73:1 rocker arm ratio = 0.552/0.552
Net valve lift at 0.033/0.033 lash = 0.519/0.519
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ICL = 108° ATDC --------(An earlier ICL synchronizes air flow capability more closely with air flow demand and makes more power.)
LSA = 114° --------------(A wider LSA reduces overlap, produces a wider and flatter torque curve; improves controllability.)
Seated Overlap = 50° ---(Limiting overlap to 60° or less improves vacuum, idle, low rpm torque and drivability.)
Seated EVO = 79° BBDC (An earlier EVO compensates for a muffled exhaust, improves idle, extends high rpm power, and reduces pumping losses.)
Seated IVO = 31° BTDC (Limiting the IVO to 30° or less improves vacuum, idle, low rpm torque and drivability.)
Seated IVC = 67° ABDC (A later IVC lowers the DCR, requires a higher SCR; can lead to reversion at idle.)

The lobes have 48° major intensity, which is very sedate by today's standards, this should provide for good longevity. 230° duration at 0.050 with a solid tappet cam is comparable to 222° duration at 0.050 with a hydraulic tappet cam. This cam would provide an engine with a very street-able power band, one that an old fart like me would enjoy; 405 bhp is enough for me.

-G