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Building 400hp Into A 5.0L Small-Block Engine - Down-Low 5.0
How To Make (Almost) 400 HP For (Almost) $1,000.
The 5.0L was originally rated at 225 hp and 300 lb-ft of torque. Though adequate back in the day, it is hardly what you'd consider a powerhouse compared to the 4.6 Three-Valve or other modern engines. To reach our goal of 400 hp, we needed to address the fundamental restriction to power production-induction flow. First on the list was a set of cylinder heads. We considered simply upgrading the existing heads with hand porting, milling, and a valve job, but soon dismissed this idea after weighing the cost versus potential power gains offered by the stock heads.
We were looking at a machining bill of nearly $350 to rework the stock heads, so we decided to purchase a set of new aluminum heads from Pro Comp. Pro Comp offered its Ford heads with both 190cc and 210cc (as-cast) intake ports. It even offers a version with the smog passages drilled and ready to accept the smog pump hardware. Since the cost of the heads was the same, we decided to go big and opted for the 210 heads. They might come in handy if we improve the motor at a later date or slip a new 347 stroker kit under the shiny aluminum heads.
The Pro Comp aluminum heads also featured 70cc exhaust ports and a 2.02/1.60 valve combination. The big news is, of course, the aluminum construction (less weight than our iron factory heads) and the significant increase in port flow-not to mention the new valves, seals, and a fresh valve job. Where the stock E7TE heads struggled to reach 160 cfm, the Pro Comp heads flowed over 260 cfm on the intake and 177 cfm on the exhaust side. These flow numbers offered by Pro Comp can be increased significantly through CNC porting for another $400-$550. Best of all, the 210cc as-cast aluminum heads can be had (with a little haggling) for less than $600 on Ebay. (We got ours for $540.)
The one potential downside to running the Pro Comp heads is the need for adjustable rocker arms and different pushrods, which further increased our budget. A set of new (hardened, but not chromemoly) pushrods set us back just $29. It was an unnecessary expense to step up to the chromemoly pushrods, but hardened pushrods were mandatory for use with the guideplates supplied with the Pro Comp heads.
For induction chores, we also went to Pro Comp, which offers one of the very best carbureted intakes available for the 5.0L, the Parker Funnel Web. The single-plane Funnel Web offers plenty of flow and power potential, and was available for as little as $125 through Ebay stores. Having tested these Parker Funnel Webs many times, we knew they worked well on modified 5.0L motors and would certainly help us reach our goal of 400 hp. Given the price, they represented one heck of a performance bargain.
After heads and intake, it was time for the camshaft. Obviously the stock 5.0L cam was not going to let our motor make anywhere near 400 hp, despite the improvements to the induction system. With cost still a major issue, we let our fingers do the walking over the magic keyboard and found some Track Max hydraulic roller cams offered by Trick Flow Specialties through Summit Racing for $164. The Track Max cam offers a 0.499/0.510 lift split, a 221/225 duration split, and a 112-degree lobe separation angle. We wanted to step up to the larger 224/232 Track max cam, but were concerned about piston-to-valve clearance with the factory pistons. In our quest to save money (it was, after all, a hydraulic roller), we simply reused the factory roller lifters.
After the compression and oil pressure test, the wrecking-yard wonder was disassembled down to the bare short-block. We installed the new hydraulic roller cam using Lucas Oil assembly lube. Although we had no way of knowing the mileage on the used motor, the timing chain appeared to be in good shape and had minimal slop. Normally we'd change this, but we elected to save the $25-$50 cost of the replacement. We coated and installed the old lifters, then installed the newly machined Pro Comp aluminum heads.