I have that XR298 sitting out on the shelf if you're interested. It has a little dyno time on it but should be ready to slide in and go. Mine was ground on 108 centers and I think we ran it installed on 106.

I ran it with 1.60 rocker arms and it made great power in my 505 and had a healthy lope at idle. Might be a tad bit more radical sounding in a 451 but that will depend on your exhaust system. That cam was making right around 680 hp in my 505 with the MP 452 heads. With my EZ heads that cam would've gone about 750 hp in my 505.