Doing a 5.3 Texas speed head swap 231/ 237 cam. measured for new pushrods with an adjustable pushrods checker and a digital caliper came up with 7.37 on average. I have comp R roller lifters and my stock replacement harden pushrods measured 7.41 think I'll be OK reusing the same pushrods? I see were people are preloading the comp R lifters .02-.03

 

Soooooo I snugged the head down and put my piston to TDC, put the stock length (measure 7.41) push rods in,set to zero lash, then torqued to 22ftpds it took just shy of one full turn(.3-.47 preload). i then turned the motor over 3 times. pulled the head and measured the clay i had on the piston. i got .206 on the intake and .240 on the exhaust. My head gasket off the car measured .60 but its compressed thickness is .51 so .206-.009=.197 intake .240-.009=.231 exhaust does this sound right?

 

That's alot more than I had, but our setups differ I'm sure. How did you measure the clay?

 

As described here is a few pictures

 

Those numbers appear to be much too large.

You can't use a lifter to do this, you need a solid lifter and you must be at zero lash. Put on a set of check springs so you can use an adjustable pushrod to achieve zero lash. I think your lifter plunger was compressing giving the appearance of much greater PTV than you really have.

 

I knew something was off you're right I forgot to switch out my springs for the checker spring to prevent the hydraulic lifter from collapsing going to redo it with the checker spring

 

When I did this I bought a pair of solid lifters to do it as well. I tried with checker springs and my hydraulic lifter and got large results like you did. According to Mamo, even with checker springs the hydraulic lifter will collapse slightly.

 

This! Use a solid lifter. Then you know fore sure. Especially when you get to clearances near 0.100"

 

I really appreciate the help I was definitely collapsing the lifter without the checker spring. I also re-measured my pushrod lengths and got a consistent 7.35 My piston to valve clearances did scare me so I called Texas speed who did the heads and they said I would be OK I got .073 intake and .090 exhaust using the clay method. They said anything below .060 in their experience is where you have trouble.

 

I did this test with 7.41 stock pushrods when i need 7.35. Will that increase my ptv when i get correct length pushrods in?