Reply to "Cylinder Heads"

You can use the Mind Train headers on either cylinder head because the exhaust manifold flanges of the Australian 2V head are large enough to provide a seal around the larger 4V headers. So that's not an issue. If your Pantera is equipped with an engine having dished pistons (1973 - 1974 Q code) installing a set of Australian 302C heads is a slick way to achieve 10:1 compression without having to replace pistons. That is an important consideration.

The intake ports of both heads are tuned more or less to fall within the power range you've described (2500 to 5000 rpm). The 2V heads are tuned for 1000 to 5000 rpm. The 4V heads are tuned for 2000 to 6000 rpm. The power range you've described is therefor in the top end of the 2V head's power band, and in the bottom portion of the 4V heads power band.

Power potential is one of the two differences between the heads. The 2V heads cannot take advantage of camshafts which lift the valves more than 0.500". Un-ported the 2V heads flow 195 cfm at 0.500" lift, and that's as much as they flow, period. Un-ported 4V heads flow 245 cfm at 0.500" lift, but air flow continues to increase as the valve opens further, 275 cfm at 0.600" lift.

Power characteristic is the other difference between the two heads. The Cleveland 4V cylinder head design was chosen by Ford because of its suitability for endurance racing, it provides an unprecedented wide and flat torque curve and a power band characterized by a strong mid-range rush. Power at lower rpm with the 4V cylinder head is peppy, smooth and linear. As long as it is not "over-cammed" the low rpm power and throttle response of a 4V motor is every bit as strong as the low rpm power of a 2V motor. A 4V motor can "light-up" the rear tires at low rpm with little effort. A 4V motor builds "steam" with engine speed and then hits a strong mid-range rush which is like the afterburners of a jet engine kicking-in! From that point on a 4V motor pulls harder and harder as the engine speed climbs (as long as the carburetor is big enough). This is an ideal power characteristic for a high performance street car, a sports car, or a GT car. Over the decades I've read reports praising the engines in high end sports & GT cars such as Ferrari, Lamborghini, Mercedes and Aston Martin for having similar power characteristics.

Some street performance and sports car enthusiasts prefer the low rpm biased power characteristic of the smaller cross-section 2V ports. The mid-range rush of an engine employing 2V cylinder heads is not as pronounced as an engine with 4V heads therefore the power characteristic of a 2V motor seems somewhat more sedate. Those who prefer the power characteristic of a motor with 2V heads feel it is more "refined" while the 4V motor is "brutish". A motor with 2V heads also lacks the endless high rpm pull of a motor with 4V heads. The 2V cylinder heads are better choices for low rpm torque applications such as towing and hauling vehicles, off-road and rock crawling vehicles and heavy vehicles in general. But I might argue such power delivery is "too typically American V8" and not as desirable for a sports car like the Pantera.

A 2V engine with its smaller valves and lower rpm tuning is a little more forgiving than a 4V engine. The 4V engine is a high performance engine, it is equipped with racing cylinder heads. The important thing with the 4V engine is to avoid "over-camming" it, set the static compression at 10:1, and make sure the carburetor and ignition are tuned well. Failure to do these things lead to unhappiness with the 4V engine.

I could live with an engine equipped with either cylinder head. As I get older I question sometimes whether or not I'd be happier with the somewhat more sedate 2V power characteristic. But then again I think I'd miss the way the 4V motor accelerates. I do not have a desire or need for a motor producing more horsepower than what can be achieved with the 2V cylinder heads, but I prefer the power characteristic of a motor equipped with 4V cylinder heads ... I've lived with it most of my life. The Pantera is an ideal vehicle for an engine with such a power characteristic, I find far easier to use the power "safely" in the Pantera than I ever did in my Mustangs.