THE BIG-BLOCK EFI TEST

Chevy High Performance - - Contents - TEXT & PHO­TOS: Jeff Hun­ey­cutt

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.

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