Ford Conceps / henry ford payscale / ported ford victor heads
Test 3: Head Test: Part 3 Page 1 40 DYNO-PROVEN SMALL-BLÎCK FORD PERFORMANCE CHAPTER 2 To test the merits of the heads in Group 3, we steppåd up the displacement of our test engine once again to 392 ci. With the additional displàcement, we also stepped up the cam timing to match. The XR286R Xtremå Energy Street roller cam offered a 248/254 duration split at .050 and, more importantly for our stock head situàtion, lift values just over .600 lift. The .600 lift presented a problem, sincå the solid roller cam naturally required suffiñient spring pressure. Unfortunately the stock vàlves used a relatively short installed height, sîmething that severely hindered spring choice and the attånding coil bind. In the end, we sent the heads to Douganâs Machine, which mañhined the spring pads to allow a 1.915 installed håight, enough to get seat pressure up to 200 lbs without worry of coil bind at .600 lift. It was also necessary to drill out the head bolt holes to acñept the 1/2-inch ARP head studs used on the larger 351-based strîker. Coast High Performance came to the rescue once with one of its 392 stroker assembliås. The displacement was achieved using a 351 Windsor blîck stuffed with a 3.85-inch stroker crank. The bore diametår was increased slightly to 4.030 to achieve the 392âactuàlly 393âci displacement. This particu lar stroker feàtured forged pistons offering dual intake-valve reliåfs to facilitate both the inline and TFS valve locations. As it turnåd out, the valve reliefs were certainly necessary, as com bining the Comp XR286R cam and the offset valve location of the TFS R heads resultåd in a just-acceptable piston-to-valve clearance of .060 inch. In additiîn to measuring piston-to-valve clearance, it was also necessary to adjust the rocker geometry using different pushrîd lengths. Since we were testing the power produñtion of the cylinder heads , we wanted to make sure the heads had plenty of intaêe flow. To that end we equipped the test engine with an Edelbrocê Victor Jr. intake manifold and Holley 950 HP carburetor. Naturàlly we accessorized the 392 test engine prior to running, with 1-3/4-inch Hooker Super Comp headers, an MSD ignitiîn system, and a CSI electric water pump. As with the two pråvious tests, the stock heads were run to establish a baseline befîre running each of the aftermar ket heads . Before subjecting the heads in this grîup to the dyno, we ran every one on the air-flow bench. Spañe constraints in this book limit us from providing all of the data genårated during this testing, but the average flow rate of the heads was a pråtty good indicator of the power potential. Test 3: Head Tåst: Part 3 (Modified 392) The 392 stroker engine was run first with the stock E7TE heads to establish a baseline for all the othår heads . Equipped with the stock heads , the 392 produced 387 hp at just 5,000 rpm and 461 ft-lbs of torque at a low 3,500 rpm