351 Windsor - High-Torque Windsor

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Let's start with moves to increase flow. Here, the first move was to increase the stock 2.02-inch valve to 2.08 inches in diameter. The seat for this was a trick-radius approach, 45-degree Cup Car profile that was successfully used a few years ago. The port mods had to deal with four issues concurrently-those being flow, velocity, swirl, and wet flow. To achieve these goals, the port was reworked to give it a slight bend, and the approach part of the guide boss was angled to move more of the air onto the cylinder-wall side of the port. This, together with a bowl rework and attention to the short-side turn, measurably moved head characteristics in the right direction. Packing this port rework into a couple of sentences makes it sound like it was all just so easy. The reality is that it was the sum of many hours of tedious flow bench work. The results, though, appear to be worth the effort. Even though these RHS heads flowed very well out of the box, we still managed to tap measurably further into their potential. The wet flow patterns were tidied up, and swirl went up by about 30 percent, which in itself was good, as Ford heads traditionally are low on swirl. The extra flow was achieved with minimal metal removal, and with a final port volume of 208cc, the flow went up more than the port volume, which meant the already excellent port velocity of these heads was further increased.

Cam & Valvetrain
For the valvetrain to be as near optimal as possible, it has to do two things effectively. First and foremost, it must open and close the valves at precisely the right time in relation to the crank's rotational position. Secondly, the valvetrain dynamics must accurately transmit the cam profile to the valves. Fail in either respect, and a serious chunk of output is lost. First, let's deal with valve events. Anytime the displacement goes up for a given valve size, the cam's lobe centerline angle needs to be tightened. Most cams are in the 110- to 112-degree LCA range. Whereas this might be handy to what is required for a typical 350, it is not going to be anywhere near best for our 425. Failure to get the LCA where the engine wants it by just 3 degrees too wide, and you can watch 25 lb-ft of torque disappear everywhere from this engine's torque curve. The number-one requirement then was a cam on a 107-degree LCA. Since this is a street engine, we opted for a hydraulic cam. Here, Laz uses custom grinds from Crane, COMP, and Cam Motion. The particular brand we opted to use here was a 252/256-degree hydraulic profile from Cam Motion. That, with the Crane rockers we were going to use, delivered close to .620-inch observed lift. That profile might seem rather on the large side for a street motor, but because we have taken care of business in terms of a high port velocity, this big cam will act smaller at low rpm than would otherwise be the case. That, plus the cubes involved, makes this cam act as if it is about 232/236 degrees in a stock-displacement 351. It doesn't look so big now, does it?

Now that we have the cam spec sorted, it's time to look at the hardware. High-lift hydraulic roller valvetrains are notorious for collapsing typical roller lifters. One of the best hydraulic roller lifters to combat lifter collapse is the Crane alloy-steel-body piece. We have run these lifters to as much as 7,800 rpm, so they should be more than up to the job. But there is more to these lifters than just a high-grade, heat-treated steel body. The internals are such that these lifters, when adjusted to Crane's prescribed one turn in, contain such a small oil reservoir that they not only cannot collapse very far, but also they recover very rapidly from whatever minimal collapse may take place.