In my opinion, an short stroke high RPM engine is usually much more fun to drive than an long stroke grunty one.
3.78" Bore is very small for an 2 valve 5.8 liter+, it does not matter if you get "better" combustion chamber, because the valve probably is so shrouded by the cylinder wall that you get poor filling and "looses" combustion efficiency by that. So then you probably need to put in smaller valves to unshroud them. And that 300cfm is probably not flowed on a 3.78" bore, I would guess. But I may be wrong.
But it depends on if you want an 300HP truck engine or an 300+HP fun engine.
I would take the fun engine, a shorter stroke engine that survives some RPM and abuse much more easily than an long stroke grunty engine that runs out of rpm.
I dont think the heat and resistance is such a big deal, unless you are going to run a lot of track, rod angle this and that, the most important is the guy who put the engine together, like Warren Johnson says " The rod only holds the piston" but of course, there is more to it than that..
Piston squirters are good for piston cooling, an 100HP VW engine from the 80s has that, then I would think an 3-4-500+ HP V8 SHOULD have it, it`s almost only just american V8s that dont have it for some reason. Any engine that is going to run continually at high speed/load likes piston coolers. Before people often cut a groove in the rods to get piston cooling, and lubrication.
I dont think there is anything wrong with a 4" stroke, but team it up with an bigger bore than 3.78 and it would be better. Cubes work, that I have experienced.. I have an 4.25 stroke engine.. But is it made for endurance racing, probably not so much..
If you can I would just go for what you think would work and try it, on a side note, most european engines are long stroke - small bore, but they are small engines that "need" the stroke. They often have short rods to, sometimes because of not much room for long. If you are used to US V8s, many european engines seems not so smart put together, from an performance view....
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