427 Side-oiler - approx. horsepower?

[Gunner]

I can't see cam alone adding ca. 130 horsepower. Cams only make the most of the other parts, and Shelby was already making an awful lot from those bits. The only engines I've seen with ~550HP have significant additions beginning with substantial improvements in displacement and breathing on top of an optimized cam. The original cam is only mild by present-day standards, not a lot of room for improvements. (Certainly not the kind of improvement that would be seen over an era street cam.)

I'm not saying you aren't being truthful, but I'd have to see documentation before accepting such a claim. It's just too easy to overstate results *and* the reasons for increases. A dyno sheet? Fine. But all too often, the claimant is forgetting about porting, port-matching, oversized valves, roller rockers, a little stroking...

[Anthony]

Originally Posted by Gunner

I can't see cam alone adding ca. 130 horsepower. Cams only make the most of the other parts, and Shelby was already making an awful lot from those bits. The only engines I've seen with ~550HP have significant additions beginning with substantial improvements in displacement and breathing on top of an optimized cam.

I built a period correct 427 comp emgine. Bored 0.017", stock stroke, 429 ci (stock displacement was actually 426). Original style (Dove) hi-riser heads, mildly ported, original (NOS) intake, original holley 780 vac-sec carb, however a reduced CR of 10.5 to 1. I installed a solid roller cam though, .670 lift.

Never dynoed the engine itself, only a chassis dyno, got 454 hp and still climbing, and max torque 488 at the wheels. A Roush 427R, on the same chassis dyno, put out 415 hp ( and still climbing) and 435 torque ( advertised at 550 hp, 535 TQ at flywheel).

Here's a picture of the engine.




Here's my chassis dyno.




Here's the best (tuned but not altered) Roush 427R chassis dyno.