Steve Baur
Former Editor, Modified Mustangs & Fords
December 13, 2010

For those of you who are just stumbling upon Project Repeat Offender, here's a quick recap. We recently hatched the idea of building an in-house Mustang to run in NMRA/Tremec True Street competition, which is a class that Muscle Mustangs & Fast Fords created decades ago and has been a sponsor of ever since. The class is aimed at licensed and insured street cars that can endure a 30-mile cruise, and after a brief cool down period, make three back-to-back passes on the quarter-mile. The top runners in this highly successful event have dipped well into the 8-second mark, so we have our work cut out for us.

In the past several issues, we've gutted our "old-ass-beige" '85 coupe, had Real Speed Racing install an S&W Race Cars roll cage, bolted up a Steeda Hardcore suspension, and mounted a quartet of Aerospace Components' killer brakes. This month, we have assembled our powerplant and put it on the dyno to show our readers what sort of steam it's making.

Back in the Aug. '10 issue of MM&FF, we documented the specifics of the Boss 351 block, and spelled out the FRPP CNC-ported Z304 cylinder heads that we would also be using. After talking with Ford Racing Performance Parts' Jesse Kershaw regarding the induction requirements of the 427, we phoned Edelbrock and ordered one of its Super Victor intake manifolds. You simply can't go wrong with the tried and true performance that Edelbrock delivers, and it seemingly has the market cornered when it comes to big Windsor intake manifolds.

We also tapped Quick Fuel Technologies for one of its trick Race Q 850-cfm carburetors. The Race Q is an all-new fuel mixer from Quick Fuel Technology (QFT) that starts with all-aluminum construction, and includes several components that are optional on many out-of-the-box race carburetors.

For our 427, we will be using a custom hydraulic roller camshaft that is similar in specifications to the one FRPP uses in its crate engines, just a little larger. The FRPP crate engine camshaft offers a split duration 242/248 at 0.050, with valve lifts of 0.576-inch on the intake and 0.600-inch on the exhaust. The custom grind that Comp Cams supplied starts with a split 248/254 duration at 0.050 and ends with a single pattern 0.609-inch valve lift (with a 1.6:1 rocker ratio), on a 110-degree lobe separation angle. It's a healthy hydraulic roller profile that we hoped would raise the power level a bit over the FRPP crate engine.

With the parts list spelled out, the motor was assembled and we had it strapped to the dynamometer at Holbrook Racing Engines in Livonia, Michigan. Whether it's NHRA/IHRA Pro Stock engines or sportsman small-blocks, Holbrook has decades of experience building some of the meanest powerplants ever to sit between two frame rails.

Carbureted engines often respond well to additional spacers between the carb and intake manifold, and Holbrook began our testing with a 1-inch spacer. We sourced a couple different ones from Edelbrock and plan to test a larger one once the engine is in the car.

After the break-in procedure was complete, the first pull netted a stout 589hp at just 6,000 rpm. Torque peaked at 552 lb-ft at 4,800 rpm. The air/fuel was a bit fat, so a small jet change was made and then the engine was pulled to 7,000 rpm. Horsepower peaked at 597 at 6,600 rpm, and torque increased slightly to 556 lb-ft.

A few more tweaks and we saw horsepower top out at 609, while torque rose to 561 lb-ft. Up to this point, the engine was run with a water temperature of no more than about 120 degrees. We wanted to see what the engine would do when it was hot, so we had the Holbrook crew make some pulls at about 160 degrees, which is probably more indicative of what we'll see after a 30-mile cruise, and the engine baking under the hood for 30-45 minutes. We've got a badass Flex-A-Lite cooling system going in the car, so we'll have to see what we can do with the coolant temperature in the staging lanes.

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At the higher water temperature, horsepower peaked at 589, while torque came in at 538 lb-ft. This is still quite a bit more than the 550 we had hoped for, so we're doing pretty good at this point. Horsepower junkies that we are, there's probably going to be a power adder on this engine at some point, but Repeat Offender should go low-10s, high-9s on motor alone.

Chris Holbrook told us that there was definitely some power left in the engine, and noted that some additional cylinder head work and port matching could yield another 20-35 horsepower. I if we wanted to see even more, a solid roller camshaft would be the next step.

Perhaps those are some good tech articles for the future. Next month, we plan to make a few front suspension and steering changes, and hopefully drop the engine and transmission in for mock up. Stay tuned.

Note
Ford Racing Performance Parts' Jesse Kershaw also provided us with a set of the company's newly minted Z304 cylinder heads (PN M-6049-Z304PA) that feature a hefty CNC milling all around. With the 2.08-inch-intake/1.60-exhaust valves moving the mixtures through the 427, the FRPP crate engines that use these heads are knocking out a healthy 535 hp with a relatively mild hydraulic roller camshaft.

With the non-CNC head and 2.02-inch valve, the compression ratio is 10.4:1. With the 2.08-inch valve used in the CNC heads, it's 10.5:1 because they take up an additional cc or so in the combustion chamber.

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