ok so i am wondering what the stock heads ptv clearance is with a cam that has .610 lift. I am running prc stg 2.5 heads and .610 lift and am curious as to how close i am. motor is a 5.3l stock bottom end, stock pistons.

thanks

 

I think you're pretty close to the limits with that cam/rocker combo.

 

grr kinda what i was thinking after reading a bunch of kinda close to my setup threads.

so how close is close with this setup. and yes i know i should have checked but i just put in new rockers with larger ratio so the ptv would have changed anyways.

maybe someone out there is running something similar can chime in.

aklowrider, did you check your ptv clearance, your cam has a little less left than mine and are running the same rockers.

Thx

 

No, I didn't. My heads have not been milled, and I'm using a relatively low (.551) lift cam. After the 1.8 rockers, my valve lift is at .583, Roger Vinci advised me not to worry until around .600 lift to start checking, unless heads have been milled. That also seemed to be the general consensus when I did my own researching on the boards. Also, since I'm using a Maggie, my duration is not too wild.

 

damn so now i wish i could check but the heads are already on and i dont have any light valve springs to check with the other method.

 

You can have all the lift you want, if the piston is down low it wont matter. Duration has more of an effect on PTV than lift. It's advisable to physically check PTV with all cam swaps regardless

 

yes i understand it is wise to do it. i changed rocker ratios and now am curious so i am asking to see if anyone out there has a similar setup that has checked there's

 

thats what i was gonna say. i would bet that cam would clear with the low duration.

 

I have no issues with my setup... My heads are milled .30 and i run a .040 head gasket, and my lift is .600+... Luckily Ed Curtis designed my cam with all of that in mind, so i figure he knows what he is doing...