Marc Christ
Brand Manager, Modified Mustangs & Fords
November 26, 2013

Nearly a year ago, we came up with the idea to compare a Ford Racing Performance Parts 363ci engine to an equally cubed tall-deck (351W) engine.

To refresh your memory, Ford Racing Performance Parts sent us one of its 363ci short-blocks as a base. The short-block features a Boss 8.2-inch-deck block, forged pistons, and forged Scat I-beam rods and crankshaft.

"Once the 347hp level dictated we went to the Boss blocks, we were leaving horsepower on the table by not over boring to 4.125 inches," says Jesse Kershaw of Ford Racing. "It picked up cubic inches and made a significant horsepower increase by unshrouding the valves without costing the end consumer anything."

To imitate the FRPP 363 crate engine as much as possible, we opted for the FRPP Z304 as-cast cylinder heads. In the valvetrain department, we turned to Comp Cams, which supplied us with a custom-grind camshaft featuring 0.580/0.585-inch lift, 236/242 duration at 0.050-inch, and 107-degree lobe separation. Comp also supplied pushrods, the timing set, valve covers, and break-in oil. FRPP sent us the correct rocker arms.

We called our friends at Summit Racing Equipment for much of the remaining engine components, such as an oil pump, oil pan kit, timing cover, and spark plug wires. We opted for an electric water pump from Meziere and a billet distributor from Crane.

We hauled all of our goodies to Auto Performance Engines (APE) in Auburndale, Florida. Owner and engine guru Kevin Willis laid his hands on our parts, transforming them into a living, breathing engine. Our task was to mount it to the engine dyno and spin it up to see how much power it could make. One problem, however—we were shy headers and a carburetor. To solve this issue, our friends at Kook's Custom Headers sent us a pair of 17⁄8-inch primary, stainless steel dyno headers with 3-inch collectors. All we needed was a carb.

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Armed With Carbs

Like the FRPP 363ci crate engine, our short-deck engine has a compression ratio of 10.2:1, which is designed to run on 93-octane pump gas. To optimize power output, we opted for an Edelbrock Super Victor single-plane intake manifold and a handful of Holley Ultra HP carburetors.

There are some who say a carburetor is inferior to electronic fuel injection (EFI). This may be true in some aspects, but there's no arguing against the simplicity of the carburetor. Tuning is done manually, and unlike EFI, few parameters are needed when a carb is deciding how much fuel to send to the engine.

Though carburetors themselves may be aging, carburetor technology is not. Holley Performance Products has recently released an all-new line of Ultra HP carburetors. With a barrage of new and improved technology, the Ultra HP line is Holley's premier street/strip line. These are available in natural finish with either black or red metering blocks and base plate, or in all-new Hard Core Gray, and ranging from 600 to 950 cfm. Other features of the Ultra HP include billet-aluminum metering blocks and base plate, a new bowl design with 20 percent more fuel capacity, and an updated main body design—all of which work together to make the Ultra HP more efficient, easy to use, lighter, and better looking.

We chose 650-cfm, 750-cfm, 850-cfm, and True 950-cfm versions, all in Hard Core Gray. Unsure which carb would work best on our 363, we tried all four. Surprisingly, they all worked well right out of the box with no tuning.

What we liked most about the new Ultra HP line is its lightweight construction. When you pull one out of the box, you can tell it's lighter than other carbs—38 percent lighter, actually. You don't have to be a carburetor expert to understand that the Ultra HP is an all-around better carburetor than its predecessors.

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Tall Boy

Since the short-deck engine yielded good results (508 hp and 455 lb-ft), we were hopeful for the tall-deck 363. It has a 3.50-inch stroke compared to the stroker's 3.40-inch stroke, and 6-inch rods, all from Scat. We used the FRPP Boss 351 block (M-6010-BOSS35195; $2,199), which has a 9.5-inch deck height compared to 8.2-inch on the Boss 302 block.

Again, we turned to Comp Cams for the valvetrain, and a custom camshaft specifically for our tall-deck competitor. It features 0.600/0.600-inch lift, 239/243 duration at 0.050, and a 109-degree lobe separation. This is a little larger than the short-deck engine, but Comp says it's ideal for the longer stroke.

30 The short-deck engine shined throughout the entire rpm range. It made 508 hp and 455 lb-ft of torque. The tall-deck competitor made 480 hp and 436 lb-ft of torque—a 28hp and 19-lb-ft difference, even with a slightly larger camshaft.

In the end, the tall deck just didn't match up, producing 480 hp and 436 lb-ft of torque. "The unshrouding of the valves certainly made a difference," said Willis. "Still, there were variables out of our control, making us question the results."

Still, the short-deck engine was the clear winner—proof that dynamite does come in small packages.