Craig, I'm building a 351W stroker (around 425ci). I have also asked around to see what parts would fit. An Edelbrock Performer will fit...as will a Victor. So you can have the performance benefits of of a single plane manifold and still have it fit under the hood.
As for
oil pans, I asked several kit car manufacturers before I ordered mine to see which would fit. They all said Canton Road Race pans work the best. I think even ERA recommends this on their webpage. Mainly for a small block, you wanna keep the pan depth under 8" or you'll have clearance problems. Other than that you should be OK. Canton makes a good pan. I have the T-sump Road Race pan. 7qts plus filter and
oil cooler....so that would be plenty for a high volume
oil pump.
Hope this helps.
Brent