Check this out...
http://www.youtube.com/watch?v=KwBSQ1IxsNo&feature=related
http://www.youtube.com/watch?v=gVt_lqaKnrc&feature=related
Actually, the 351 Cleveland has the same bell housing as the 5.0l (302). The 2V or the 2V Aussie heads would be better for Bronco as far as more torque at lower rpm's due to the smaller valves (Aussie 2V heads are quench design which raises the compression ratio also). But, if you're going to rev it up, go with the 4V Cobra Jet or 4V Boss heads. Here's some more information...
In the small capacity displacements, the 289/302 was a great little engine - and it went on to become even greater in the eighties and nineties - but as car size increased in the U.S. Ford decided that they needed larger capacity from the small block to generate more torque to move the heavier cars. Hence they developed the 351W, but even from its inception, Ford appreciated that while the 351W gave the capacity required, it was a marginal engine from the point of view of developing more and more horsepower as the performance wars of the late sixties escalated. So Ford designed the 351C.
The 351C was designed from the top down with the major amount of effort put into designing the best and most efficient cylinder heads that they could to allow the engine to breathe, and so to rev.
The 351C has a canted valve cylinder head, with splayed valves set at slight angles to one another, unlike the 351W which has parallel valve stems. This canted valve arrangement makes the 351C cylinder heads bigger - wider - than those of the 351W, and as a result it has wider rocker covers. As an aid to identification, the 351W exhaust manifold to cylinder head surface is almost vertical as viewed from the ends of the engine, whereas the 351C has an exhaust manifold to cylinder head surface which sits at 45 degrees and is as near parallel to the side of the block. This can be difficult to see if an engine is in place.
Ford U.S. came up with two basic versions of their 351C, the 2V and the 4V. The 2V stands for, as it does most usually, 2 venturis, and describes a two barrelled carburettor. American 2V 351Clevelands came equipped with two barrelled carbs and as such the engine was designed to be the common version of the engine fitted to non performance cars. To this end, Ford U.S. designed a set of heads for the 2V that had smaller inlet and exhaust ports to promote better low down torque. These small port 2V heads required their own inlet and exhaust manifolds to mate up with the heads and they also had smaller valves. Initial rating of the 2V engine was 250hp.
The 4V was the performance version of the 351C, and was so named because it was designed to have a 4 venturi or four barrelled carburettor. To feed the extra fuel through the cylinders, the 4V heads had much larger ports than the 2V, and as result required their own matching inlet and exhaust manifolds, and larger valves. The combination of bigger, more effective 4 barrel carburettor, bigger valves and bigger ports ensured that the fuel mixture could get into and the exhaust gasses get out of the combustion chamber more effectively than in the 2V heads, hence the 4V engine would rev better and as a consequence, produce more power. The 351C 4V was rated, in 1970, at 300hp.
Engineering is often a compromise, and such was the case with the 4V. The valves, and especially the ports were so big that the inlet mixture could slow down in its passage into the combustion chamber. This decrease in velocity, most noticable at low revs, left the 4V versions of the 351C feeling kind of sluggish as the cylinders struggled to fill. The 2V, with its smaller ports and valves, could keep the mixture velocity up which promoted better cylinder filling, and gave the 2V its impression of greater low down power, torque and flexibility. Of course, this is what Ford U.S. wanted, promoting the 2V as the torquey grocery getter engine, and the 4V as the “let it rev and feel the power” engine.
In the U.S. for the very brief period that the musclecar/horsepower craze continued during the 351C’s early life, the 4V spawned a small clutch of developments:- the 1971 Boss 351; the 351CobraJets, or CJs; and four bolt mains caps.
This is where the 2V and 4V descriptive terms become somewhat entwined. The distinct separation that applied in the U.S. between 2V and 4V ensured that a 2V Cleveland had a two barrel carb and inlet manifold, small inlet and exhaust ports and an enlarged chamber volume, while the 4V Cleveland had a four barrel carb, large inlet and exhaust ports and reduced size chamber volume which created a higher compression ratio. Now the Australians introduced a 2V head that took either a two or a four barrel carb inlet manifold, and had a large, but not as large as the U.S. 2V, open chamber size, plus, for further confusion, they introduced a 302C engine that had 2V heads which had a two barrel carb but a chamber volume smaller than anything the U.S. had offered, even on their highest performance Clevelands.
I'm running a 4V dual plane aluminum intake on a set of 2V heads. It really woke up the engine! Hope this helps.
Welcome Visitor! Please take a few seconds and 
