I think you need to read Jim Hands article a little more close. I believe he used several different cams in his 455 engine in a 4100# car with a 3.55 ratio. Quite different than a 400 engine...and still we do not know head codes.

Cams are related based on other factors and are based on which heads and car they were installed in. Cams can be rated for HP and torque only with other known parameters such as head CC, carb, exhaust, rocker ratio and compression.

For instance, a 400 GTO with the same heads and cam as a 400 Firebird the same year would show 360 HP in a GTO because the GTO was heavier. The 068 in a GTO was rated at 360 HP and in a Firebird 335. HP numbers also depend on the carburetor and exhaust manifolds.

What head codes are you running? That could be an issue. As well, the carb linkage could be binding up, not tuned or you may have a vacuum leak. What are you seeing for vacuum at the port?

IMO, you will NOT see 360 HP with a blend of 70/30 in a 400. If you had the CR to attain 360 true flywheel HP, the 3.08 rear would be a detriment as Firebirds in the HO or RA realm were advertised at 335-340 (under rated) yet were optioned with 3.55, 3.90 and 4.33 rears. If you had true 360 HP, you would be hard pressed to see the benefit as 3.08 would not allow the engine to dig in early and hit your HP/RPM band as the cam/head/carb/exhaust package would allow.