Are they overblown or what? How many of you have actually experienced it? I've had several vehicles with them and never a failure. Stock Lightning with 85,000 on it when I sold it - flat tappet, and I built a 400 about 10 years ago with a Comp 268 High Energy (loved it) never a problem, put about 10,000 miles on it and sold the truck, it's still running around as far as I know. My current 400 has 4,000 miles on a flat tappet and upon teardown it looks great. All lifters and lobes look like new.

I'm pondering camshaft choices for my build. I *want* to go roller for the durability standpoint, but am nervous about drilling and tapping the lifter valley, and running the spider system as I plan to run the truck hard. Linkbar lifters are nice, but will wreck my budget.

I actually like the comp XE flat tappet choices better than what is available in rollers (very few choices)

I should have about 9.5 to 1 Static compression, wondering how much duration I need to keep a liveable Dynamic compression ratio on premium pump gas.

I'm thinking about a cam in the low .500's lift, 268-270ish duration at .006" and exhaust biased a little.

Thoughts?

I hear horror stories on forums about flat tappet failure, but the only ones I know outside the forums it's pretty obvious why their cams failed = operator error.

How much lift will the stock heads take also? With the proper springs of course.

.566" from a comp 270 too much?

 

Most cam failures can be traced back to improper installation, wrong oil or both. Lots of people still have no idea what has happened to our oil over the last few years. People just throw a big cam in with a stock valvetrain and expect it to work without checking everything, problems get worse when you add in machine work. There have been some cases of just plain bad cams and lifters from time to time. Comp had a bad run not too long ago.

 

That's the part that worries me. I've heard cases of that happening to guys on forums, but my only experience in real life is with guys that shouldn't be touching motors in the first place, and are very lucky that's all that went wrong was the cam.

Then there is my dad who has gone through 3 motors in a chevy farm truck. He's a smart man, but it's his fault too. He hasn't run the proper oil despite what I've told him, and doesn't even change it often enough.

 

^THIS.
Most cam installers do not check for end play. That can come back to bite you. Another area of failure is not using any assembly lube and then expect just the oil to protect the cam or lifters. You just can't do that any more. The government mandated that the zinc and phosphorus content in oil be severely lowered to protect the catalytic converters. There are even a lot of 15W-40 diesel oil that have had their additives lowered. Isn't it funny how a lot of high-priced "flat-tappet" oil is the same stuff we could get off the shelf (on sale, maybe) for $1/quart just 10 years ago?
As far as the bad cams and lifters, that's more common than you think. A lot of camshaft billets or even complete camshafts are being made in China. You think they really care about hardening the lobes properly? Just yesterday I bought some flat tappet lifters for my 4.0 Jeep. They were a name brand that everybody has heard of and should trust....but the lifters were made in Mexico.
My wife and I had the conversation just yesterday about how she wants me to keep our vehicles on the road forever. Unfortunately, the quality of replacement parts is getting so bad or the parts get obsoleted so fast that trying to keep an older vehicle on the road is getting next to impossible.

 

I know it's going to keep me up at night and I don't want to have to worry about it. I'm going roller. I talked to comp about their nitriding services for flat tappets, it runs about $100 dollars. That puts them right up there in price with a roller. I'm not happy with Comp's choices for roller though. I'll be getting with Buddy Rawls for a custom hydraulic roller.

 

I don't blame you a bit. I'm building a 393 next spring and I'll be using a '95 F4TE block that is equipped for all the necessary roller equipment.

 

After waiting, waiting and waiting to get my budget padded enough for the roller and lifters I'm sick of waiting.

I'm gonna run a Comp XE262H Flat tappet, their lifters, Vavloline VR-1 racing oil / break-in additive added and report back. Really wanted to go roller, but I can either get a roller cam and lifters, or flat tappet and all the rest of the parts needed to finish the engine. It's just too damn expensive. I'll report back when she's runnin'