Rebuilding The 360 Short-Block Engine - Necessary Improvements

Was It Worth It?
After the engine was reassembled and put back in the car, it was time for some dyno thrashing. We spent the day at Norris Motorsports in Ocoee, Florida, on Mike's Dynojet chassis dyno. With some simple tuning, we had to settle for 292 hp. There is definitely more horsepower in the engine, and I think our cam choice may have something to do with these numbers. Not that the Lunati cam is the issue. On the contrary, our choice of a 235 duration at .050 is the factor; another time where the advise of the cam manufacturer should have been asked. On the plus side, when we upgrade to a better set of heads, this cam will be more at home. With our J heads sporting a 1.88-inch intake valve, there is definitely a bottleneck hampering the flow. We surmised this by the peak horsepower coming in at around 5,000 rpm. Our first pass gave us baseline numbers of 242.3 hp at 5,000 rpm, and the torque numbers were 284.1 lb-ft at 3,000. With some simple tuning, we increased those numbers to 251 hp at 5,000 rpm and 291 lb-ft of torque at 3,600. That's an increase of 9 hp and 7 lb-ft of torque. Minimal maybe, but when you factor in that the factory rated this engine at 255 hp at the flywheel, we increased the numbers at the rearend to mimic the factory flywheel numbers. If you factor in the parasitic loses through the tranny, the Gear Vendors unit, and the rearend, we did improve our little 360. We wanted to hit the spray while on the dyno, but I forgot to bring the guide that let me know what jets to install for each horsepower shot of nitrous. So, in the interest of not installing the wrong jets and melting down a piston, (or having a loud "ka-boom" come from under the hood), we left the 75hp jets in and gave it the old winder-up-and-try-it blast. This time, the junkyard engine responded with 292 hp at 4,900 rpm, and 367 lb-ft of torque at 3,300. Sure, the numbers may be a little soft, but keep in mind that the bottom-end of this engine is 30+ years old, and a beating is a beating. It handled it nicely. Next, maybe we should try a good set of heads, and let this seasoned veteran breathe a little better. Sounds like a plan to us.

Dyno Run 001
2,500 - 5,500 rpm
Barometric Pressure 30.19 inches
Intake Temperature 86.6 degrees
Jetting: 76/79
No carb spacer
Timing 34-degrees total

Dyno Run 007
3,000 - 5,500 rpm
Barometric Pressure 30.23
Intake Temperature 91.2 degrees
Jetting: 72/72
1-inch tapered four-hole spacer
75hp nitrous
Timing: 34-degrees