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If you are having issues with a HFT the LAST thing you need is a solid roller. How are you going to get enough valve spring on it? I say 200 on the seat is the sweet spot, and 180 is the bare assed minimum. If Lunati says less, they are lying or stupid.

5/16 pushrods are marginal for a SFT and way too flimsy for any solid roller, unless you can get .116 wall stuff, and even then it ain’t a SBC. The lifter side rocker geometry on SBM is atrocious at best.

My suggestion to the OP is to take a breath or two, slow down and figure out why this cam went flat and fix that. You already have roller rockers...why not a good solid flat tappet grind? 130 on the seat and 320ish over the nose and if it’s not some Comp MM style lobe it should be drop dead reliable.

As NM pointed out above do not keep adding zinc to the oil. Zinc is required, but more zinc isn’t good. When you mix crap like that, you make very Tribologist in the country flip their collective lids. Any oil worth a crap is designed as a complete package. When the end user adds crap to it, you change the balance of the additive package of the oil.

My suggestion is to use a break in oil next time. A real, dedicated break in oil, and add nothing to it, unless you are a certified tribologist and know exactly what you are doing.

Most cam failures happen on initial fire up. The engine gets cranked on too much, and by too much I mean it should fire up just like it will when it’s tuned correctly. There should be fuel in the carb, the distributor should be set at a MINIMUM of 40 total so when the engine is at break in RPM you have that much total on it. Retarded timing generates heat, and heat kills parts.

You must verify everything before cracking it off...full battery. Known good ignition. Known working carb. Get it running and get the RPM up to 2200-2500 and then vary the RPM a bit to keep the oil splash on the cam and keep the lifters rotating.

Which reminds me of another issue. Lifters that are too tight in the bores and the lifter doesn’t rotate. This is a lobe killer. With a light oil on the lifter it should slide down the lifter bore on its own weight. If it won’t, stop and fix it. Blocks that have been thermally clean and shot blasted almost always have lifter bore issues as the top of the bore gets peened over and the lifter will slide into the bore but not rotate.

It’s time for a slow, methodical autopsy on this and find the reason for the failure. A solid roller isn't the cure for everything cam failure related.