"We'd be happy with 480 hp on motor, any more we'd consider it a gift from the racing gods," is what we thought as we travelled up Interstate 15 with our Rapp Racing small-block securely strapped in the back of our diesel. Considering the list of off-the-shelf parts, mild hydraulic-roller cam, unported heads, and 91 octane pump gas; 475-485 hp at around 6,000 rpm was our guess for this latest stroker recipe—enough to put our lightweight early Nova project car within striking distance to our quarter-mile goal of 10.00. With nitrous oxide, we'll surely be in the single digit zone.
Besides breaking it in and gauging the power output, putting it on the engine dyno allowed us to test a couple different carburetors; a pair of Black Diamond Q-Series carburetors from Quick Fuel Technology, a 750-cfm (PN BDQ-750) and 950-cfm (PN BDQ-950) version. The idea was the larger carb would work better on spray and with a loose enough converter, could also work on the street (if we wanted to pay for the extra fuel). Of course, many gearhead thoughts racked our brain on the way to Westech Performance group in Mira Loma, CA, but mainly, we anxiously looked forward to hearing the roar of power through the pipes once the NOS Big Shot plate was activated.
The combination is a Mark Rapp-built 385ci small-block with 6-inch Scat rods, 10.65:1 compression from Mahle PowerPak pistons, a hydraulic roller from COMP Cams with 230/236 at 0.050, Summit Racing 200cc aluminum heads, RHS single plane intake, Moroso oiling system, Hooker 1-3/4 headers, Quick Fuel Technology carb, and a Pertronix ignition. For somewhere between $8,000 and $10,000 in parts, depending on your exact combination, you can order these components from Summit Racing. For our build, we set out to see what kind of power can be had with this off-the-shelf combo, and we think most would be surprised, we certainly were.
Before the dyno testing at Westech Performance Group, we actually ran the engine on this nicely built run stand at Rapp Racing in Huntington Beach, California. The snappy revs sounded very promising, and probably the best part … no leaks!
At Westech, Steve Brule’ and Troy Goldie unloaded our 385ci and hooked it to the 902 SuperFlow dyno.
We learned since we’re running a roller cam, the break-in procedure is not as delicately specific as flat-tappet cam is.
We like to run a FilterMag on our oil filters, especially on a new engine. he high-strength magnet holds finite bits of metal that would otherwise be circulating in your oil system. The filter is Moroso's Race Oil Filter (PN MOR-22460). It has a 27-micron filter capability, anti-drainback valve, and a high burst strength.
Cool details like this Lokar Performance locking dipstick (PN ED-5001) makes this engine look sweet and the black anodize matches the theme.
After Brulé set the dyno to modulate the revs for a few minutes, the 385ci was ready. The first pull of the morning, at a conservative 31-degrees of timing, netted 474 hp and 475 lb-ft of torque at 5,100 rpm, very nice numbers for the initial pull. We still had timing, jetting, new oil, and a bigger carb to try before the day was through.
Westech’s SuperFlow 902 is set up with a powerful Aeromotive fuel system that can handle big horsepower. This pump setup is more than enough to handle our power output, even with the nitrous at full spray.
A few more pulls closer to 6,000 rpm and our little stroker was pumping 491 hp and 489 lb-ft on 91 octane; the timing and jetting was still untouched.
Changing the timing from 31 to 35-degrees pushed our dyno numbers over the 500 mark. At this point, we were ecstatic since we weren’t done tweaking it. The TCI Rattler and TCI Timing pointer made setting timing a breeze.
Once the engine had a couple pulls under its belt, Steve changed the oil and replaced it with fresh high-zinc 10W-30 from Lucas Oil Products. This change alone gave us close to five more horsepower and torque.
The Black Diamond Q-Series Quick Fuel carburetor ran pretty good out of the box, but Brule felt it was a bit too rich and could use a downsize in jetting.