Jim Smart
January 10, 2011
Contributers: Benton Jackson Photos By: Benton Jackson

MCE Big-Block Build Tech 598ci Big-Block Engine Build, Part 3 When Marvin McAfee of MCE Engines penciled out his 598ci T-Rex vision, his goal for this brute Ford big-block was between 800-900 horsepower, with a comparable amount of torque using a single four-barrel carburetor. To stand any chance of getting there, he needed Ford Racing Performance Parts' new M-6010-A460 race block with its thick wall construction, four-bolt mains, siamesed 4.600-inch bores, and steel main caps.

McAfee would also need a cylinder head, camshaft, and induction package that would deliver the kind of power that he had in mind for an engine of this size. Of course, a lot has changed even in just three years, when it comes to heads and induction. Savvy engine builders are getting in excess of 1,000 hp from the A460 Ford block from a variety of new cylinder heads and induction systems that have come into the marketplace since this project was first hatched. We could look at all of them, however we were commited to Ford Racing's M-6049-C460 sportsman cylinder head.

The C460 356-T6 aluminum cylinder head is a high-port job designed for professional racing-it's not a street head. Valve angles are 7 1/2 degrees intake and 8 degrees exhaust, void of side angles. Chamber size is 65 cc's with the 2.450/1.900-inch suggested Manley Performance stainless or titanium steel valves. Port and chamber sizing and shape are based on the Ford Racing Yates cylinder head. Sold only as bare castings, the C460 heads retail for about $875 each.

Just as with every cylinder head, custom porting can make them into really hot performers. Jon Kaase Racing Engines of Winder, Georgia, does a custom-ported Ford Racing C460 head that flows 500-plus-cfm on the intake at 0.800-inch lift, and 350-plus-cfm at 0.800-inch lift on the exhaust. Ready to bolt on with Pro Stock port work, a competition valve job, Manley Performance titanium steel valves, PSI valvesprings, and titanium retainers, these giant heads retail for $6,800. This is a little more than our budget for this build will allow, but it shows you the potential of these heads when a big-block Ford expert like Kaase gets a hold of them.

For our test, we'll show you what can be done with these heads basically right out of the Ford Racing box with precision valvetrain components from Jesel, Comp Cams, and Manley Performance.

PowerHeads of Wildomar, California, cleaned these castings up with a port match for improved flow. However, no specialized port work was performed. Installed valvespring height is 1.900-inches. Seat pressure (valves closed) should be 228 pounds at 1.900-inches. Open pressure should be 702 pounds at 1.200-inches, with spring coil-bind at 1.090-inches. As assembled by PowerHeads, our C460 cylinder heads flowed 380 cfm at 0.700-inch lift on the intake side, and 225 cfm at the same lift on the exhaust. Low- and mid-lift numbers were also quite impressive.

Our Ford Racing/MCE Engines big-block buildup hasn't been the easiest engine project to undertake due to its limited production nature. We have a block and heads you don't encounter every day, which makes it tricky to find compatible components. Because the C460 isn't a mainstream off-the-shelf cylinder head, finding just the right headers exhausted most of our resources. When we contacted Custom Performance Racing in Gardena, California, it was glad to accommodate us and knew exactly what we needed to make the most of our T-Rex 598. McAfee wanted a custom equal-length step header with 2 1/8-inch primary tubes that opened into 2 1/4-inch pipes and dumped into 4 1/2-inch collectors. We had to go with a 4-inch collector because necessary raw materials (4 1/2-inch pipe) weren't in stock at the time. The upside of going with 4-inch collectors is improved backpressure along with velocity for good scavenging depending upon valve overlap. Custom Performance Racing was able to fabricate a set of long-tube, equal-length step headers just in time for our T-Rex 598 dyno session.

We did run into fitment issues with our headers, however, as JGM Performance Engineering in Valencia, California, had a scattershield that was not compatible with our custom headers. There just wasn't enough space for the step headers and equal-length tubes to fit around the dyno bellhousing. Jeff Lattimer of JGM went above and beyond the call of duty when he modified the bellhousing to fit the headers. Unfortunately, this cost us a lot of valuable time that could have been spent dyno tuning. You'll want to talk it over with your dyno operator beforehand regarding the headers you'll be using. Many dyno operators keep a number of headers on hand to fit the dynamometer machinery, but some don't.

We went to the dyno expecting 800-850 hp and a comparable amount of torque. Some may consider this conservative, considering engines of this caliber can make 1,000 hp and more than 900 lb-ft of torque without breaking a sweat. McAfee takes a more conservative approach to maintain durability. He wants an engine that will stay together, while delivering planet-rocking power. You can't go rounds or make it to the winner's circle if you're picking your rods up off the ground.

We were pleasantly surprised that we well-exceeded our power number aspirations with this build. Our horsepower and torque numbers prove Ford Racing has one heck of a casting in its C460 race head considering the flow numbers shown above. Depending upon your budget, the ported Jon Kasse C460 head and a change to a larger carburetor would likely take the combination even further. Make no mistake, though-915 hp is enough to propel your modified Ford well into the 8-second range at the dragstrip. Check out how it went down.

Dyno Pull 1

Holley 1,150-cfm Dominator
(PN 0-80673)
Jetting: 0.90/0.90
Ignition Timing: 32 Degrees BTDC at 3,500 rpm
Step pull in 500-rpm increments beginning at 4,000 rpm

RPM HP TQ
4,000 567.1 744.6
4,500 672.7 785.1
5,000 764.1 802.6
5,500 821.4 784.4
6,000 859.7 752.5
6,500 895.4 723.5

In Pull 1, we learned that the 598 was lean and in need of larger jetting. We started with 0.90 jets in the primaries and secondaries. Based on air/fuel ratio and brake specific fuel consumption (BSFC) numbers, McAfee concluded we needed to step up to 0.92 jets in the primaries. Benton Jackson, MCE Engines fuel system specialist, took care of this in short order. Ignition timing is conservative at 32 degrees BTDC to eliminate any chance of detonation and engine damage. McAfee's regimen includes step pulls in order for the engine to stabilize before rpm increases.

Dyno Pull 2

Holley 1,150-cfm Dominator
(PN 0-80673)
Jetting: 0.92/0.90
Ignition Timing: 32 Degrees BTDC at 3,500 rpm
Step pull in 500-rpm increments beginning at 4,000 rpm

RPM HP TQ
4,000 503.9 661.6
4,500 690.4 805.8
5,000 784.1 823.6
5,500 838.3 800.5
6,000 878.9 769.3
6,500 909.8 735.1

On the second pull, we were still too lean. McAfee increased jet size one step at a time again as a measure of fine-tuning. "Quantum leaps in jet sizes only add to the confusion of tuning," McAfee tells us, "at one jet size at a time, you know back to back from one pull to the next whether you're rich or lean without having to backtrack." The 0.92 primary jets did add 14.4 hp and 21.0 lb-ft of torque. McAfee elected to go up a jet size in the secondaries to 0.93 to see what happens next.

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Dyno Pull 3

Holley 1,150-cfm Dominator
(PN 0-80673)
Jetting: 0.92/0.93
Ignition Timing: 32 Degrees BTDC at 3,500 rpm
Step pull in 500-rpm increments beginning at 4,000 rpm

RPM HP TQ
4,000 521.5 684.5
4,500 698.1 814.8
5,000 787.4 827.1
5,500 848.1 809.9
6,000 883.4 773.3
6,500 915.7 739.9

In the wake of our third and final pull due to time constraints, our 598 T-Rex produced 915.7 hp and 827.1 lb-ft of torque. We are thrilled these numbers surpass McAfee's expectations. However, we're convinced that with more dyno time, this engine would be courting the 1,000hp mark. And if you run out of dyno time, you can always continue your testing once the engine is in the car and at the track. Keeping good records will go a long way in documenting the changes and performance or your engine.