Words and images by Richard Holdener.
Last time, we took a look at the new 540-inch big-block Chevy combination from BluePrint Engines (BPE). In addition to offering plenty of displacement, the big-block stroker was designed specifically for use with power-adders, meaning boost or nitrous (or both). We started things off by uncrating the 540 and immediately subjecting it to a dyno session. After a few break-in cycles, the 540 was run in anger in naturally aspirated trim to the tune of 649 hp at 6,100 rpm and 629 lb-ft of torque at 4,500 rpm. Satisfied it was now ready for the first of many power-adders, we installed a Zex Perimeter Plate nitrous system. Run with 250hp jetting, the 540 big-block responded with 937 hp and 891 lb-ft of torque. It is amazing how effective the combination of this large-displacement crate-engine and nitrous was, but we knew the nitrous kit was just the beginning. Having run nitrous through the big-block, it was now time for some boost.
For those who missed the first installment, here is a rundown on the BPE 540 (nicknamed The Mad Adder) we were working with. The 540 arrived to us having already seen dyno verification (a printout of the dyno run was included). Basically, this bad boy was ready to rock and roll once removed from the crate. To ensure plenty of strength for power-adders, the 540 featured a number of upgrades. Of course, their own heavy-duty four-bolt block was an excellent starting point, to which they added a 4340 forged steel crank, forged H-beam rods, and matching forged aluminum pistons. The rotating assembly was topped with a set of free-flowing, as-cast, aluminum BBC rectangular port heads that featured 119cc combustion chambers (PN PS8013). The result was a boost-friendly compression ratio of 8.5:1. To ensure power production under boost, the 540 stroker also featured a healthy, solid roller cam profile that offered 0.652/0.652-inch lift, a 255/262-degree duration split, and 114-degree LSA.
As we indicated in the first part, the 540 big-block was supplied as a long-block, meaning the customer would be required to add the induction system and distributor. For the nitrous test, we added a Weiand single-plane intake, Holley 950-cfm Ultra XP carb, and MSD distributor along with the nitrous kit, but all of this was removed to make room for the first of many badass boost builders. To further illustrate how effective the lower-compression 540 was, we decided to add boost from an 8-71 supercharger. Nothing looks cooler than a massive blower sticking out of the hood, especially a polished 8-71 equipped with dual-quads. The 8-71 kit, including the polished Blower Shop 8-71, was supplied by the good folks over at Speedmaster. Their blower kit included a dedicated intake manifold designed to accept the big-boy blower. The kit also featured blower studs, drive pulleys, and gaskets, along with the Gilmer belt, tensioner assembly, and adapter to mate the drive pulley to the damper included on the BPE crate engine. Additional components included a dual-quad adapter, blower snout, and spring-loaded blow-off valve.
There were a couple of additional components required to get the 8-71 installed and ready to run, including a pair of 950 XP Holley carbs controlled by a dual-quad throttle linkage (also from Holley). Once installed, we set up the blower with a pulley combination designed to produce a minimum amount of boost. It’s always better to start low and build boost rather than set the combination on kill right off the bat. Run with a 50-tooth blower and a 50-tooth crank pulley (1:1 ratio), the blower was spun at the same rpm as the engine. This produced a peak boost pressure of 4.3 psi and allowed the BPE 540 to produce 792 hp and 720 lb-ft of torque. Stepping up to a 55-tooth crank pulley (keeping the 50-tooth blower pulley) resulted in a jump in peak boost to 6.1 psi. The increase in boost pressure pushed the power peaks to 845 hp and 770 lb-ft of torque. The next pulley swap combined a 65-tooth crank pulley and a 55-tooth blower pulley, which resulted in a peak boost pressure of 7.8 psi. This pushed peak power up to 881 hp and peak torque to 804 lb-ft. The final test used a 48-tooth blower pulley while retaining the 65-tooth crank pulley. This was as fast as we could spin the 8-71 with the supplied pulleys. The result was an amazing 939 hp and 866 lb-ft of torque at 11.1 psi. With more pulleys we could have added more boost, but that’s another story for another day.
1. Designed from the get-go for boost, the BPE 540 was delivered in long-block form. The 540 stroker featured a static compression ratio of 8.5:1, free-flow aluminum heads, and a healthy solid roller cam. The BPE long-block was ready for whatever power-adder you decide to throw at it.
2. Popping the valve covers revealed a spring package designed for use with the roller cam, 1.7:1 roller rockers, and even a dedicated stud girdle system.
3. To establish our baseline, we first ran the 540 in naturally aspirated trim. Equipped with a Team G intake, Holley 950-cfm Ultra XP carb, and MSD distributor, the stroker produced 649 hp at 6,100 rpm and 629 lb-ft of torque at 4,500 rpm.
4. Off came the Weiand intake and on went the dedicated 8-71 blower manifold from Speedmaster. Supplied as part of a complete kit, the intake featured provisions for the thermostat housing, a spring-loaded blow-off valve, and aluminum blower studs (do not over tighten!).
5. The biggest chunk of aluminum was, of course, the polished 8-71 from The Blower Shop. Capable of supporting over 1,000 hp on the right combination, the 8-71 looked right at home on the BPE 540.
6. The blower kit from Speedmaster included a blower snout, tensioner, and tensioner pulley.
7. Boost was adjusted by pairing blower and crank pulleys of varying tooth counts. Either increasing the tooth count of the crank pulley or decreasing the tooth count of the blower pulley can achieve an increase in boost pressure. The highest boost level was achieved with the largest (65-tooth) crank pulley and smallest (48-tooth) blower pulley combination.
8. Speedmaster supplied the necessary cog belt to drive the blower. Make sure not to over-tighten the blower belt. They don’t need nearly as much tension as typical serpentine belts.
9. Speedmaster included this dual-quad carb adapter and gasket to mount a pair of 4150 carburetors on the 8-71.
10. Holley stepped up with a pair of 950 XP carbs and dual-quad linkage for our blower test.
11. Ever present during testing was this MSD billet distributor and a 6AL ignition amplifier (not shown). The blower size and position necessitated a small-cap distributor.
12. The BPE 540 was run first at low boost then we stepped up the blower speed until finally reaching a peak of 11.1 psi. Run at this boost level, The Mad Adder BPE 540 produced 939 hp and 866 lb-ft of torque. Best of all, it did this non-intercooled. This would be a fun combination for the street or the track and just shows how much performance a few pounds of pressure can add to the equation.
13. Run in naturally aspirated trim, The Mad Adder 540 thumped out an impressive 649 hp and 629 lb-ft of torque. The baseline test was run with a Weiand single-plane intake, Holley 950-cfm Ultra XP carb, and MSD distributor. After installation of the 8-71 blower kit from Speedmaster, the peak numbers jumped to 939 hp and 866 lb-ft of torque at a peak boost level of 11.1 psi. Nothing screams look at me like a BBC stroker sporting a polished 8-71 blower!
14. We loved how well the BPE 540 responded to the 8-71 blower, but the best thing about the blown big-block was how easy it was to add power. Simply swapping the blower and crank pulleys increased the speed of the supercharger. Increased speed brought increased boost, which in turn brought more power. Running 4.3 psi, the BPE 540 produced 792 hp, while 6.1 psi brought 845 hp. Stepping up to 7.8 psi allowed the 540 to produce 881 hp, and the final test at 11.1 psi produced 939 hp. Best of all, the pulley swaps took only a minute or so and required no changes to timing or carb jetting.