THE BIG-BLOCK EFI TEST
Prestige Motorsports tests two different Holley EFI setups on a new 632ci big-block build
Prestige Motorsports tests two different
Holley EFI setups on a new 632ci big-block build
Prestige Motorsports has established itself in the last few years as a major player when it comes to horsepower production. The engine builders in Concord, North Carolina, regularly ship engines all over the world, and they are constantly testing and refining new engine recipes in order to stay on top in the horsepower wars.
Prestige already has several big-block Chevrolet packages for everything from 489 to 598 cubic inches and as much as 725 horsepower. But more is always better, so we stopped by to check out the assembly of their newest 632-cubic-inch bruiser.
The goal of this build is an engine that produces locomotive levels of torque throughout the rev range with the ability to do it all day long. It’s based on a World Products Merlin IV cast-iron block with 4.600-inch bores. That, combined with a forged Eagle 4.750-inch stroke crank, makes for 632 total inches for a street machine engine.
We’ll detail the complete build here, but what’s cool is that the mad scientists at Prestige do more engine testing than practically any other engine builders we know. So while this engine was on the dyno, they wanted to test out different EFI setups to see how they would work on this combination.
Prestige has a longtime working relationship with Holley when it comes to their engine management and fuel-injection systems, so both EFI setups will be run off of the same Holley HP EFI engine control unit for consistency in testing. In both tests, Prestige will also use a Holley
single-plane, port-injected intake with a Dominator-sized flange and Holley 66-lb/hr injectors.
For the test, we’ll be running one of Holley’s 2,000-cfm, four-barrel billet throttle bodies on a Dominator flange and testing it against an Edelbrock cast-aluminum elbow with a Holley 105mm single-blade throttle body.
The big 632-inch engine will demand tons of air to make maximum power, so it will be interesting to see if the LS-style 105mm throttle body can keep up with the race-spec 2K Dominator throttle body.
So check out the build and stick around for the testing. This should be fun! CHP
01 | The plan for Prestige’s 632ci big-block is a build that produces enough torque to make a diesel locomotive blush. Plus, of course, when you have a brand-new, 750-horsepower engine on the dyno, it’s the perfect time to do a little EFI testing, right?
02 | The foundation for this build is a World Products Merlin IV cast-iron block. This is the 10.200-inch tall-deck version, which will allow extra stroke and the cylinder walls can handle a bore up to 4.600-inches in diameter—which is exactly what we are using.
03 | The camshaft is a solid roller from Comp Cams. It is ground with 270/280-degrees of duration at 0.050-inch lift on 110-degrees of lobe separation. With the 1.7:1 ratio rockers, gross valve lift will be 0.715-inch for the intakes and 0.717-inch for the exhausts.