#'s Matching 340 build
Ouch! Yes, agreed that exhaust manifolds are a huge obstacle to overcome, even with chemical porting and extrusion honing. And the cam would have to be a custom affair to overcome those manifolds. Pistons may be a little more doable than at first glance. While they are not my favorite due to the oil ring drainback slots and boat anchor weight, if one could come up with a set of low compression TRW 360 forgings... The .300 inch thick crown can afford to give plenty of material to make it fit, and also add some dish for valve relief. But, sometimes just because you can do it doesn’t necessarily mean that’s the way it should be done. But I wouldn’t be able to resist trying!