A couple years ago, we fixed an engine someone else built, that had issues. Here is a link to the original post.
It had a 236/244 Isky cam in it, but the customer didn't like the idle, and other aspects of that cam. He pulled the engine out, and brought it back to get a smaller cam installed. He told me he wanted a smooth idle, lots of vacuum, torque, and didn't want to rev it over 5000 RPM! He also wanted to dyno it. I installed the BOP one piece oil pan gasket he brought in, also. His car has a Tremic 5 speed, and a 3.23 rear.
Here is the combo.
Mid 70's 455 block and crank
1968 #16 heads[9.2:1 compression]
KP Hypereutectic pistons with a 30.5 cc step dish
5140 Tomahawk rods
Stock iron Q-jet intake with Q-jet carb of unknown origin, rebuilt
Scorpion aluminum roller rockers
Lunati VooDoo HFT cam, 227°/233° @ .050", 268°/276° adv., ground on a 110° LSA[off the shelf part]
RA exhaust manifolds with 2 1/4" outlets
MSD distributor, 36° total timing[made best power here]
First pull yielded only 370 HP, and 486 FT. LBS. Suspicious, I check to see if we were getting full throttle. Turns out we weren't at all. The secondaries, were only opening maybe halfway. I readjusted the linkage, and we got full throttle. A/F numbers were really lean also. We made a pull, and the power came up quite a bit. A/F ratio was still lean, so we made some adjustment, and it got better. A/F was still in the 14's to low 15's in some spots, but since this engine is going to be run at an altitude twice what it is here, we left it there, since it will fatten up in the higher elevation. We probably could have got another 10 HP or so if we dialed in the carb, but then he would have to readjust it when he got it back, so we left it where it was. Here is what it did. Not bad for a small cam, and low compression. No signs of detonation on 91 octane pump gas. Normally, I wouldn't put a cam this small in a 455, but customer wanted smooth, and torquey, so he gets it!
Basically from 2700-4000 RPM, it made right around 500 ft. lbs. or more, and from 4500-5200 RPM it made right around 400 HP or more, but carried the power out even further than I had expected for such a small cam[still made 380 HP at 5700 RPM, only 22 down from peak].
Also, at 1800 RPM, it made the same torque as a stock 400 made from 3200-3600 RPM, depending on the configuration! Ought to be a nice cruiser engine. BSFC numbers were mainly in the .4's, with most being .42-.44 range.