Reply to "Solid Flat Tappet Street Cam"

Here's your cam specs as I would detail them:

Advertised duration at unspecified tappet lift = 292°/292°
Duration at 0.050 inch tappet lift = 240°/240°
Gross valve lift at 1.73:1 rocker arm ratio = 0.552/0.552
Net valve lift at 0.021/0.021 lash = 0.535/0.535
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ICL = 106° ATDC --------(An earlier ICL synchronizes air flow capability more closely with air flow demand and makes more power.)
LSA = 108° --------------(A wider LSA reduces overlap, produces a wider and flatter torque curve; improves controllability.)
Seated Overlap = 76° ---(Limiting overlap to 60° or less improves vacuum, idle, low rpm torque and drivability.)
Seated EVO = 76° BBDC (An earlier EVO compensates for a muffled exhaust, improves idle, extends high rpm power, and reduces pumping losses.)
Seated IVO = 40° BTDC (Limiting the IVO to 30° or less improves vacuum, idle, low rpm torque and drivability.)
Seated IVC = 72° ABDC (A later IVC lowers the DCR, requires a higher SCR; can lead to reversion at idle.)

Based on valve lift this is a 415 bhp cam, peaking at about 6200 rpm (4V cylinder heads). In order for the engine to have good over-rev, the exhaust will need to be low back-pressure. The low back-pressure exhaust would help the low rpm performance too.

In terms of drivability the things that work against you are the 76° of overlap and the intake valve opening too early (IVO = 40° BTDC). I'm surprised you had 12.8 inches at idle. Some guys would like the rough idle. Its a cam designed to appeal to drag racers (and parking lot cruisers), with a rough idle, steep torque curve, and narrow power band. There's no way to adjust the timing and "fix" this cam. It is what it is.

The 4V Cleveland heads are tuned to make peak horsepower at 6500 rpm. The way you "retain" low rpm power with 4V heads is to keep the overlap and intake duration conservative, keep the DCR around 7.6:1 to 8.0:1, use a carburetor with annular boosters and a dual plane intake manifold with a full height plenum divider. You don't need a big cam to make power with the 351C-4V. In fact Ford intentionally designed the 4V heads so that the induction system defined the power band and made the horsepower ... thus allowing good performance even though a "street friendly" cam is installed. The 351C 4V makes more horsepower and has more high rpm performance with 50° of overlap than most engines have with 76° of overlap. This is the drum I beat continuously.