Now, don't misunderstand, Keith Black hypers are good pistons, I just personally don't like that big gap required for their top ring. Keith Black Performance Pistons. For theirs, they recommend a much wider top ring gap. I have cast 10:25 to 1 flat tops now. When rod tries to pull the piston back down, it chunks off the top ring land. I use Speed Pro (Federal Mogul owned) hypereutectic pistons which use a normal top ring gap. 115 Posts . 319 Posts . If you don't use the wider top ring gap, they ring ends can butt at the top of the cylinder (hottest part) and stick. I trust his knowledge just wanting to see if anyone esle has had the same problem. I'm in the market for pistons. KB pistons make more HP by reflecting heat energy back into the combustion process and, as a result, the top ring runs hotter and requires additional end clearance. Since 1922, United Engine and Machine have been building a reputation for their pistons of the utmost quality. What are your thoughts on Speed Pro vs KB hypereutectic pistons for street performance use, say around 450 to 475 hp range. I hear bad things about Keith Black Hypereutectic Pistons. Bought a set of KB pistons(9.2 to 1) for my build and curious if anyone knows what the 2 extra rings that came with the set are for. Some people say they are fine if you install the rings properly. These pistons mostly contain high silicon aluminum alloy. You can now use the stock 4.0 rods with the Keith Black "ICON" forged pistons, because of their wrist pin location. This makes them not only light weight but extremely durable. Had oil consumptions problems on pretty new 408sbc. Or can anybody suggest a brand. Thus, they carry and manufacture Keith Black pistons. Discussion Starter • #1 • Apr 27, 2007. The pistons are Keith Black hypereutectic 10.5:1 cr. Top. Keith Black makes a high end hyper piston. I think it truly depends on experience. Ive had some people say speed pros arent the best. I've never seen a problem with them. If you had a good one you praise, a bad one you bash. They have several different stroker build options/combos listed, from mild to wild. The Keith Black pistons unique thermal conductivity, ring location and varied end use requires special attention be paid to top ring end gap. Made from hypereutectic 390 aluminum alloy, Keith Black Signature Series pistons are CNC-machined for accuracy and are heat-treated with 16 to 18 percent silicon. Keith Black also offers KB Signature Series performance pistons for Ford, Chrysler and GM muscle car applications. Are Keith Black Hypereutectic Silv-O-Lite pistons any good etc.? HP fan Member Posts: 91 … My machine shop guy said this is a common problem with these pistons, and KB blaims it on tight ring gaps. Do you think either brand others a distinct advantage or disadvantage, in terms of reliabilty and performance. Keith Black Silvolite and Federal Mogul/Speed Pro are the main players in the hypereutectic piston market, and we have used both brands in … I stumbled across a very informative 4.0 stroker page from some Jeep guys, and you no longer have to use the 258 rods. Discussion Starter • #1 • Nov 6, 2004.