Paint it, Clear it or Let It Rip?
the only clear i've had any success with is VHT 1200 flame proof and applied following their directions to a T. it's held up and not yellowed much and seems to have a similar wear/lifespan as any other engine paint.
i would not leave it raw
duplicolor engine enamel is pretty good for the price and it's widely available. it also sprays pretty nice.