Checking valve to piston clearance on intake at 10*ATDC results in 0" clearance as the valve opens and on exhaust 10*BTDC results in .090" clearance as the valve closes. Looks like new 1.5 intake rockers are in order.
Can someone tell me proper way to map the lobes at .050, .100, .200, .300, .400, .500, .600, .700? Max lift came in at .710" on int. and .668" on exhaust. I use 1.6/1.5 HS rockers currently, soon to be 1.5/1.5, Cam lobe spec .4300/.4300.

This is what I do.
Read the degree wheel at each lobe lift desired (dial indicator, 0.020", 0.050", etc)

I was told years ago by a very good Mopar Sponsored SS NHRA SS racer to check them at 5 degree increments, not at .050, .100,.200, .300 and up to max lift in .100 increments
When I'm checking and setting up the intake lobe centers, I check them at .200, .100 and at .050 before and after max lift I have seen all of them the have exactly same as well as seeing two or three different ILC in one degree differences

Thanks guys. If there's time i will give it a try tomorrow.

I believe the lobe shape can make calculating ILC at 0.050 and 0.300 a couple degrees different. Some lobes are the same, some are not. You can really see a difference at low lobe lifts (0.010") since the entry and exit lash ramps can be different.

I would borrow or try to get my hands on a 1.5 first might not provide much (enough) change.

The HS rockers i have are sold as 1.5, but measure closer to 1.55 as others here have found as well. Their 1.6 is the same, 1.65 from my measures.

Then I really don't think going from 1.55 to 1.50 will get you there. retard the cam a couple of degrees and see what you get.

That will put the exhaust vale closer to the piston and it has .090" clearance as is. Gonna order up new 1.55(1.55) HS intake rockers and go with it.

good luck

Thanks, really appreciate the info.

Changing the intake from 1.6 rockers to 1.5 will likely give you roughly 0.043" at max lift. But at 10 ATC, the lobe is open about 0.190-0.200" so the reduction in valve lift at that point will be roughly 0.019"
Changing the ICL position 2 degrees will change it roughly 0.015". You can actually make this change now, and see how much it helps you.

Also if you are using checking springs this will be totally different with the load of there real spring.

I see. Looks like a cam redegree is in order than. I hate the idea of retarding the cam thou. Cam is ground on a 108, maybe just put it in straight up will give the clearance i need to make it work with a 1.5 (1.55) rocker. How much performance will be lost doing this i wonder.

Something else i notice is, the exhaust vave opens as stated on cam card, but closing spec is way off according to my measures. Should close on 25.5, i think it was actually closing at 75. It opens 70.
The intake open spec is consistant with the card,but the closing point is not. What is the proper way to get the closing points?

Jim, thank you for that example chart ! very informative to me !

if your running a solid roller lift cam with good spring pressures and an automatic tranny I've got away with .060 exhaust valve to pistons and .050 intake valve clearances in a bracket motor that got raced a lot with no issues other than not much exhaust soot under the valves position on the piston tops
You can always cut the valve reliefs in the pistons in the motor with the proper tools, Isky use to offer them, not sure if they still do or not

Cab, what is your method of checking v/p clearance with heads on motor?

light weight checking springs
A friend of mine work for a natural gas CO in SO CA, he gave a dozen or so lightweight springs that came out of their regulators that work excellent
If they show .050 or more on the intake at zero lash and .060 on the exhaust side, I know I have more than enough P to V clearances with the regular springs and valve lash
Depending on the cam lobe size and LSA I see V to P on the exhaust valves I see the least amount of P to V at TDC and on the intake valves from 5 BTDC to 15 ATDC depending on those lobes

Dave, the only real way to know what your P/V is is to use clay on the pistons and use the springs you are going to run and the head gasket you are going to run at the lash you want to run and turn it over.

If you do the soft spring method you will have way more clearance than you think you do. This is because no matter what rocker you have, if it’s built correctly the ratio will be .3-.5 or so higher than the nominal ratio. Has to be because all rockers flex under load.

I’ve seen guys machine the valve pockets because they did the soft spring deal, or change the ICL because they used soft springs when in reality under actual spring loads they had more than enough clearance.

I stopped using soft springs to check P/V in about 1986. It’s just not a good way to check that.