What do I do with this Engine

At a minimum stock valves need to be replaced with single groove one piece units. Have the heads gone through, replace guides and seats if necessary. Have all that quoted first as it might be cheaper to use a set of alloy heads. Which heads you use will determine which intake you use. Unless this is a concours build, I typically shy away from reusing stock intakes, there are better options out there that are affordable and aluminum. You can make a decent street engine with 2v or 4v heads, but if either need a ton of work, they're not really worth it over a set of aluminum units.

I'd go with a hydro roller cam. Yes they cost more then a tappet cam, but the failure rate of those as of late are something you really want to avoid. Some guys will say lifter bore bushings are necessary, I say they're only required if the bore to lifter clearance isn't correct. Which cam you go with will determine your rocker requirement. If stock rockers won't work, and your heads still have the pedestals, there are bolt on kits that will work for most street builds. Make sure to use the correct lifters, and that they don't expose the oil galley at max lift.

Keep the overbore to a minimum, a lot of machinist like to jump right to a .030 overbore, but with thinner cylinder walls that's to be avoided if it isn't necessary. You'll want a flat top piston, and Hypereutectic pistons are fine for a street build. Rods need to have their nuts swapped for arp units, or swap to arp studs and nuts and then have them resized. If you're keeping the stock crank, have it checked dimensionally, ground if needed, and polished. The balancer needs to have the rubber rebuilt or replaced, and I typically upgrade the flexplate to something that's sfi rated. The bottom end should be balanced after swapping off the pistons, it will likely come in lighter.

I prefer to upgrade the oil pan to something with more capacity, but a street engine wouldn't exactly require it. Get a new oil pump and have it gone through, deburred, and the clearances all checked. Standard volume is fine, as is standard pressure if you're below 6500 rpm. Replace the cam bearings and use the ones from tim meyer so you won't have to deal with restrictors. Shoot for a main bearing clearance of around .002", Rod bearing around .0025", and you should be able to use a 5w30 without issues.

That's all the thoughts I have for now. Sorry that they're not very organized. 

in todays aftermarket parts atmosphere an old school hydraulic flat tappet cam is pretty much a No-Go. cam core metallurgy & heat treat are highly suspect and grinders are not providing the correct lobe taper, lifter metallurgy, heat treat & machining of the foot radius is near impossible to find a satisfactory product. some still swear by Hy-Lift Johnson as the only brand that will pass QC but i really have no idea? there are some outfits that will retouch a set of lifters to true the foot, highly recommended if you choose to try a hydro-flat cam. but guess what? you'll find the same horrendous quality issues on the roller cam side as well! chinesium abounds. yes there are some vendors that supply a quality product and i suppose weighing their asking $ is worth it considering the alternative. regardless of specifics any cam & all the lifters need to be inspected properly & thoroughly by someone qualified. that may even be you if you're knowledgeable or educate yourself and buy some tools? making sure there are 16 lifters in the box does not constitute a proper inspection. brand / style / design of a roller lifter in a Cleveland block can be an issue in / of itself. some roller lifters have their oil hole located so that it aligns with the oil galley in the Cleveland block, these lifters can cause the oil pan to be pumped dry before you can get out of the driveway. there's a simple fix to prevent that and allow any brand / part number roller lifter to work in a Cleveland block but it adds yet more $ to the cost of success. bronze lifter bore bushings with a restricted oil orifice is a 1 step fix for the 351C 'oiling problem'. Dennis Wydendorf sells a kit www.lifterboretools.com that can install the bushings at home or you can have your shop do the deed. there are short & long bushes, the long bushes add a level of insurance against the roller lifter exposing the oil band at max lift. 

i'll cut it off here & leave you with this, Building a Cleveland? Read This,