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Aftermarket Parts - Are Premium Parts Worth The Price?

We Test A Pile Of Speed Parts To Discover

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'This was dyno thrash week, and we went through the Summit catalog like kids at Christmastime. The conversation went something like this: "This will be great-test that tunnel-ram against a single four-barrel manifold . . . See that new Edelbrock dual-quad setup? Test that too . . . Hey, Holley's got three different 750 mechanical secondary carburetors. Which one will make the most power and which one costs the most? Run 'em all and find out . . ." It was like combining stream of consciousness with dyno testing. Before I knew it, I was staring at a 6-foot-tall pile of parts in my shop that took two truckloads to haul to Westech for a marathon dyno session.

We also enlisted Car Craft's brand-new JMS-built 383 small-block Chevy for the beatings, which would consume 35 gallons of pump gas and three long days of 6,500-plus-rpm blasts. At the end, we had Westech's Steve Brul asking, "You're not coming back again for awhile . . . are you?"

After cleaning the last bit of synthetic oil out from under our fingernails and pondering whether we qualified for the Guinness World Record for the most small-block Chevy intake manifold swaps in a single 48-hour period, we did manage to compile a rather sizeable database for the parts we tested. We discovered all kinds of surprising stuff. We learned that Wilson tapered carburetor spacers rock; that 7,000 rpm can tweak a set of valvesprings in one pull; that tailpipes cost power but not where you think; that Weiand makes a very strong dual-plane Air Strike intake manifold; that an Edelbrock nostalgic dual-quad setup looks pretty cool on any small-block; and finally that Dart's CNC 227 heads matched with a big cam can make wicked horsepower. All told, the thrash was a total success. And you're the big winner, because now you have all the information you need on these parts to decide if they're worth emptying your savings account in the name of horsepower.

The Power Source
All the tests in this section were performed on the same 383ci small-block Chevy machined and assembled by JMS Racing Engines. Since this small-block was destined for a very hard life on the dyno, it made sense to plug in a rock-solid rotating assembly that could take the abuse, which led us to a complete bottom end from Lunati. One small shift from the norm was to start with a one-piece rear main seal block of '88-and-later vintage. To give it a fighting chance to survive, JMS added steel four-bolt main caps to the center three main bearings, requiring a careful boring operation to make the bearing housings all round. We opted for the standard 3.75-inch-stroke steel Lunati crank with a one-piece rear main seal, along with Lunati's forged Pro Mod rods and a set of flat-top, forged Wiseco Pro Tru pistons with two 5.4cc valve reliefs.

Stroker packages, especially the 383 Chevy, often need a little clearancing around the bottom of the cylinders, and this block was no exception. Once the block was cleaned and the forged pistons assembled on the Lunati rods, it all slipped together with the 11/416-inch rings and bearings supplied with the rotator package. We selected a pair of Dart Pro 1 Platinum 215 heads as the starting point for our small-block test mule combined with a Comp Cams Xtreme Energy XR280 mechanical roller cam (cam specs can be found in the Dart cylinder head test sidebar). Compression came in just a hair under 11.0:1, but even with the smaller cam detonation was never a problem. We also planned on testing a larger set of Dart CNC 227 heads combined with a bigger XR292 cam, so Comp supplied 0.080-inch-thick-wall pushrods along with some lash caps we needed to ensure the rocker arms would clear the larger-diameter valvesprings. After that bit of custom engineering, the engine came together very quickly, including a three-piece front timing cover and a Hamburger oil pan from Summit Racing to button everything up with Fel-Pro gaskets and ARP bolts.

Parts List
Lunati 4340 stroker rotator assm. EA62 Summit Racing $3,470.39
Steel main caps SB350C12 JMS 225.00
Hamburger's oil pan 1088 Summit Racing 239.88
Comp Cams XR280 roller cam 12-771-8 Summit Racing 255.95
Comp Cams lifters, Endurex roller 888-16 Summit Racing 516.99
Comp Cams timing set 3100KT Summit Racing 176.69
Comp Cams pushrods, 0.080 wall 7972-16 Summit Racing 135.95
Comp Cams three-piece cover 210 Summit Racing 229.95
Comp Cams Magnum rockers, 1.5 1305-16 Summit Racing 275.95
Comp Cams billet-timing set 7100 Summit Racing 101.69
Dart 215 Pro 1 Platinum heads, pr. 11611123P Summit Racing 1,439.90
ARP head bolts 134-3601 Summit Racing 59.95
ARP 7¼16 rocker studs 134-7103 Summit Racing 35.95
ARP Perma-Loc 300-8243 Summit Racing 53.95
ARP intake manifold bolt kit 134-2001 Summit Racing 19.95
ARP distributor stud kit 130-1702 Summit Racing 3.88
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