These are the AL heads I want Because My 4v heads with the dot and quality parts makes a mushy bottom end. https://www.trickflow.com/parts/tfs-5161t003-c01
Here's a good example of why you want to change out the stock OE valves. Not
my motor, just saw it on the 351C.net site.
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Been there, done that. You don't want to take a chance.
FYI you can get a new set of Severe Duty Stainless Racing Valves from SI Valves for $160. They will have a shipment of 300 sets coming in around mid to late December 2019. Also as many have said valves from a BBC will fit the Cleveland 4V heads.
Be careful with cheap on-line BBC valves; OEMs had 3/8" valve stems while aftermarket are 11/32" and will fit a 351-C. I suppose one could have stock Ford iron guides bored out to 3/8" and gain considerable weight- which will limit rpms. Stem lengths also vary, making pushrod length a variable as well with such a combination. To use an adjustable valvetrain, the engine needs hardened pushrod guides so at least 3" of one end of all 16 pushrods will need to be hardened. Stock 351-C pushrods are not and will wear in two, while spreading steel scrapings throughout your engine. There are no cheap shortcuts in building a 351-C.
Check your "ss" valves for magnetism; some places weld ss heads to plain steel stems so some parts of such a valve will be magnetic. What we're advocating is NOT having a weld (and potential failure at speed) to deal with, not whether there's stainless in there or not. And there are some odd mixes of stainless steel that are no good for severe service like in an engine valve. A few will actually rust and are weakly magnetic. Far east backyard shops also make up their own "grades" of stainless and other metals that the SAE have never seen before. Name brands with years-long good reputations are best.
Hi Jack...good advice as usual. I checked my valves that are out for a head rebuild (71 4V) and very interesting, the intakes are VERY magnetic, yet the exhausts (with rusty tips) are still magnetic but barely. I would love to know what they are, but the heads have been rebuild and there are things I don't like, so anything but the actual head casting is likely going to be replaced.
Way back in the mid-60s, GM, Ford and others used a nickel alloy for the hotter-running exhaust valves, welding them to a mild steel stem for penny-saving. My '65 Corvair had such exhausts that were thus magnetic only on the stems. Back then engines seldom turned even 6000 rpms so most owners didn't notice the weld was a potential weak spot. Except on hard working air cooled VWs or 400 Ford motor homes climbing a long hill in summer towing a trailer....