Though offered with full CNC porting, we selected a set of as-cast heads from Pro Comp for this low-budget build. The aluminum Pro Comp heads featured 320cc intake ports, a 2.25/1.88 stainless valve combination and flow numbers that easily eclipsed anything offered by the factory, especially our cast-iron, peanut-port heads. Wanting to maximize the power of our head selection, we set aside some of our budget for additional head work.
In addition to surfacing the heads to bring the chambers down to 116cc to help improve the static compression ratio, we also enlisted the aide of Bryce Mulvey of Dr. J's Performance to fine-tune the as-cast heads with a performance valve job and minor bowl blending. Our relatively mild cam timing could not take full advantage of the high-lift airflow offered by a set of fully-ported CNC heads, but the mild head work offered by Dr. J's would yield big low-lift dividends on the as-cast heads. Check out the before and after airflow numbers, taking note of the low and mid-lift flow gains. Given the max lift of 0.540 offered by our Summit Racing cam, we wanted to concentrate all our flow effort below 0.550 lift. That is exactly what the valve job and minor porting performed by Mulvey accomplished. The Pro Comp heads were torqued in place using a set of Pro Comp BBC head studs.
The finishing touches on our BBC build included a set of 1.7 ratio aluminum roller rockers and single-plane Screamer intake manifold from Pro Comp, though we also tested a Weiand Team G (which added roughly $105 to the total bill). The intake was fed by what we thought was a Holley 750 double-pumper carb purchased off eBay. To our surprise, the part number revealed a larger 850 Holley (PN 4781S). With so many carburetors listed for sale on eBay, readers could easily duplicate the cost.
For a distributor, we ran a stock HEI pirated from the wrecking yard with the motor. For a total cost of $19 (with wires), we made sure we got a distributor with both cap and rotor in good condition and ready to run. It took a little mixing and matching on our part, but there were plenty of HEIs in the wrecking yard available for us to piece together a usable combination. We also snagged a set of stamped steel valve covers for the paltry sum of $5.
All that was left was to install a set of spark plugs, Lucas oil and break-in additive and Hooker 2.25-inch dyno headers (not included in the total). The motor was run on the dyno with a Meziere electric water pump.
Before letting the hammer fly, we subjected the 454 to a pair of computer-controlled break-in procedures to seat the new rings and ensure the cam and lifters were properly acquainted. After this, the rat was run in anger to the tune of 565hp and 532 lb-ft of torque. Not only had we reached our goal of exceeding 500 hp, but managed to do so by a healthy margin. It appeared the new rings were money well spent. Despite its humble beginnings, the wrecking yard 454 offered a respectable torque curve, bettering 500 lb-ft from 3,500 rpm to 5,900 rpm.
Now it was time for the juice. To help us reach our secondary goal of 700 hp, we installed a low-buck NOS Sniper nitrous system on the 454. The NOS Sniper kit included everything we needed to add as much as 150 hp to the 454.
To ensure our cast pistons survived the test, we replaced the 91-octane pump gas with 114-octane race fuel and retarded the ignition timing six degrees before hitting the button. Some minor tuning with the bottle and fuel pressure allowed us to dial in the air/fuel mixture to a safe 11.8:1. After the minor tuning session, we were rewarded with peak power numbers of 736 hp and 691 lb-ft of torque.
We had officially reached our goal of producing 700 hp and did so with a total expenditure of just $2,403. The total cost could be reduced further had we secured a running short-block that did not require new rings, but all in all, we'd say a 700hp BBC for less that $2,500 makes good financial cents.