With the 1.6 I built that is in BRGRacer's car I installed MMS shim under bucket lifters, and the full supertech valvetrain (valves, springs, retainers). I weighed all the stock pieces and then all the replaced pieces. It dropped an entire pound off the valvetrain. Doesn't sound like a lot but ask anyone who has driven that car how much it loves to rev and how fast it will. At 8krpm is absolutely sings. I'd love it if integral would go even further and make hollow cams for the miata. That could easily drop another 2+ pounds and free up a ton of wasted power.

And the reduced valvetrain mass requires less spring rate, which means less lobe resistance, and so on. Did you get the specs on the springs? We used the 1.6 EProduction valve train in the Motorola cup, just made some caps to sit on the valve stem tops and then set lash as usual shims under the bucket. Our spring rate was about ~15% less than stock.

We checked and reset lash after every race. That was usually a four hour endurance race plus another 2 hours of track and maybe more if we did any testing.

But for most boosted cars there's better places to spend the dough if you've already got HLAs.

Kind of OT, but should valve keepers/locks be replaced on a rebuild? Do they normally wear?

They should not wear at all. If they do you will find a dropped valve in your motor.

If the oil changes and flushed still dont make your HLA noise go away, you go out and buy new ones. Take the cams off, plop them in, and put everything back together. Still much easier than shims.

People don't put in SUB lifters because the maintenance is easier.... This thread is full of noob fail.

the integral stage 2/1 cams are baby cams so i would assume your fine. as for 8-9k with hla's, i dont know about all that

Yeah, I'm looking to keep my car comfortable driving on the street. I probably don't need anything over 7500rpm since my Greddy will probably crap out around there at 15psi, if not sooner. With proper cooling and all new HLAs, I'm sure they'll hold up fine for my purposes. If not, I can always install solid later and hate myself anytime they start to tick.

I do not know how many people have the shim unders here, but it was a very good modification for me. I never have to mess with it, and it made a considerable amount of power on my normally aspirated motor. I would definitely recommend it to any one who is doing any kind of top end work.

For all those concerned about lifter noise, I never had that knocking noise from my shim unders compared to what HLAs gave me.