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. 

This Cleveland build question still comes up a lot, even after 51 years being out of production. Most builds still look to be mild, and many things are not needed for a mild build.

I define mild is not shifting beyond the typical dual intakes capability, which is about 5000rpm. If you can live with that, then those OEM and normal dual planes are fine, as is the stock oiling system and most of the OEM level parts. But as said often, the valves are all suspect to come apart at high rpm and old age. 

So always have the heads reworked, confirm the valves and seats are not original. Replace those as needed, plus the guides. If you want or need more rpm, 6k or more, don't do it without upgrading the oiling system. The Cleveland, all 385 engines(400,351M and 351C), they have massive cam oil galleries, with huge holes resulting from the lifter bores intersecting those galleys. That's great for very high rpm racing where the whole engine will be upgraded to handle those constant rpm conditions.

But for normal applications, and some time at a track, high rpm will kill the bearings at some point if you allow the excessive oil flow to the heads(it starves the bottom end of oil). That requires limiting the oil flow to the heads, which comes from the lifters, and that extra oil coming from the cam oil galleys.

The ideal way to fix that is to install lifter guide bushings, made with .060" holes in them for proper oil flow(not too much). That's a serious machining operation and many shops will be unfamiliar with that, and not cheap. The old school method is perfectly fine for most people, the oil restrictors that used to be common to do for any Cleveland back in the 70's etc. But you have to find a shop which knows what that is and how to do it. The restrictors are installed in a couple of critical places, a couple of main bearings etc. It also includes special machining care of the crank journals and the bearings. All of that should not be expensive, but many shops will not be familiar with it, so beware as you hunt for a shop.

Doing the oiling system upgrades will make the engine reliable to shift at 6k or so, and then the intake should not be any plain dual plane. The RPM Air Gap is an excellent intake to run at 6000rpm, the others are not at all. Example, toss a Performer intake, that's for stock replacement use, not for shifting higher.

Do not install a high volume oil pump, that is only for serious high rpm racing, with a much larger oil pan capacity. Those oil pumps do not solve the oil starvation issue of the main and rod bearings. Skip a high volume pump, just use a high quality Melling etc, have it taken apart and carefully inspected. Last I saw, Melling sold such a pump which was "blueprinted" by them, at a reasonable price, say $75 instead of $50.

The 2V heads are great for rpm up to 6k or so, they are great for almost any build. But the 4V heads will shine above 4000 rpm, and be mediocre below 3k. The 4V heads are a waste if the engine never sees 5k, the 2V heads will be better overall in such a mild build. Give the 4V heads respect by running a 6k or more head/intake/cam system, with the oiling system upgrade. They will reward you if you do that, using a roller cam for sure.

A milder engine doesn't need the most expensive cam etc, but as said before, the flat tappet cams are not surviving break-in very often these days. A basic flat tappet cam of any type, plus lifters and pushrods, may cost under $500 easily. Roller lifters plus cam and pushrods, will be easily above $1100. For that kind of money, if the rpm is needed, make it a custom roller cam, that will be worth the tiny cost of custom over Off The Shelf(OTS cam).

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 https://www.lifterboretools.com" rel="nofollow - 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,

https://forum.grantorinosport.org/ford-351c-and-335-series-engine-information_topic18192.html" rel="nofollow -

https://forum.grantorinosport.org/ford-351c-and-335-series-engine-information_topic18192.html" rel="nofollow - https://forum.grantorinosport.org/ford-351c-and-335-series-engine-information_topic18192.html

Parts selection at this time is very difficult, tons of parts are poor quality due to recent worldwide source issues. Flat tappet cams are a major problem right now because of it, and the lifters are also likely to be low quality.

So for the foreseeable future, all parts should be chosen with great care, by very wary. All businesses have been scrambling for new sources for their products, since the Covid worldwide lock downs. That is the cause of most QC issues, and it isn't fixed yet. A couple of years from now there will be plenty of stocked parts that were made years earlier, so this problem will take years to correct.

Try to buy parts which are from long time great brands, hopefully those will have less QC issues.