Manley 221443 valve springs with K1 cam?

I bought a SR71 top end from Kaase complete with his K1 camshaft and T&D rocker arms. The Manley catalog says 0.730 max valve lift but the K1 is 0.780 to 0.790 lift. I double checked with Kaase and they said that those are the springs that they use with that cam. We put everything together and checked for coil bind and so far it looks like it works so we're going to run it this way but it does bug me a bit. Does Manley have the wrong specs on their springs? Or is Kaase pushing the limits on this part? Anyone have experience running these springs with this cam for a full season of racing?

What IH? 2.0?

AndyF wrote:I bought a SR71 top end from Kaase complete with his K1 camshaft and T&D rocker arms. The Manley catalog says 0.730 max valve lift but the K1 is 0.780 to 0.790 lift. I double checked with Kaase and they said that those are the springs that they use with that cam. We put everything together and checked for coil bind and so far it looks like it works so we're going to run it this way but it does bug me a bit. Does Manley have the wrong specs on their springs? Or is Kaase pushing the limits on this part? Anyone have experience running these springs with this cam for a full season of racing?

The valve spring installed height is probably a little taller than Manley initially specified..

Did you stick a feeler gauge between the coils? How much clearance was there?

Are you readings in the Pic's with .000 Lash?

What is the installed height?

If I was going to upgrade springs I would do it before you run them. Those Manley's are over 500 bucks new. Once run not so much.

Yes I checked with a feeler gauge and there is space between multiple coils so it is probably 0.050 away from coil bind. Just seems odd that the spec is so far off. The installed heights are all in the 1.950 to 1.960 range so they are close to spec. I guess we'll run it as is since that is what Kaase recommends. The readings shown are with lash, ready to run. The T&D rockers are 1.75 ratio so the lift is a little more than what the cam card says.

Probably not a high rpm type of engine even at 521 inches. I haven't run this combo before but I'm expecting the power peak to be around 7000 rpm. I have a Victor intake on it at the moment so I'm thinking that the smaller port size in that intake will kill some rpm.

I found an old post from Kaase where he talked about these valve springs and how they've run them up to 8100 rpm with his K1 camshaft. So I guess they must be okay if he has that kind of experience with them. He said in the post that on paper it doesn't look like they'll work but that in fact they actually do work.