Originally Posted by panic
The Pierce sidevalve 366" (3.500" × 4.750") L8 is (AFAIK) legal for XXO, which has a 375" displacement limit (or sleeve the 385" engine down?).
I suspect that, in addition to the obvious age and wear problems (where to get spares? although pistons in that size are very common), the cranks are fragile due to length, 9 main bearings, and should be examined closely for cracks. A current design harmonic damper is strongly recommended.
If you decide to modify the engine, pretty much the same things that apply to the Chrysler 265, Ply-Do 230, Pontiac 239, etc. SV L6 engines (reground cam, bigger intake valves, careful seat preparation and block relieving, stronger valve springs, minimal quench distance) are sources of information. The intake and exhaust designs will be fairly similar to Buick OHV L8 engines as to grouping, firing order, etc.
The exhaust ports are individual, with some adjacent (but not siamese): 1, 2 adjacent to 3, 4 adjacent to 5, 6 adjacent to 7, 8
The intake looks like 4 siamese ports: 1-2 3-4 5-6 7-8
Cam lobe placement: Ex In Ex Ex In Ex Ex In Ex Ex In Ex Ex In Ex

Great pictures: http://www.claytonrestorations.com/posts/bwg_gallery/1932-pierce-arrow-engine/#


Panic, your cam lobe placement looks screwed up 10 exhaust on an L8? and 5 Intake??

1953 Chevrolet 3100
261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done
In the DITY Gallery
Video of the 261 running

1964 GMC 1000
305 Big Block V6, sm420, the next cab off restoration