I'm needing some input from some head experts.

I have a set of cnc345 440-1 that are going on a 605. With 1.6 rockers my lift will be .800. So I need to install 2.100 springs to have enough clearance. I've bought Manley +.100 retainers and +.050 keepers. With .062 spring cups my install is 1.980! So I'm looking at the spring seats, and there seems to be plenty of meat there. Indy sez cutting .050 is no problem. My question is...How much meat is really there? Has anyone cut them .100? I see no way to measure the thickness. All input is appreciated!

Thanks...RIP

Last year I had Modern report my cnc 325 cc heads to 355. I had cut the spring seats .060 for the cups.Jeff cut through at the top edge of each seat.He was able to weld it back up.With the stock lenght valves you have all you are going to get.Might try a longer valve or change springs to one that will work with your cam lift at 1.980.

Hope this helps.

Something is odd.
My Indy 440-1 heads were setup by Dwayne Porter (fast68plymouth) with the Manley valves made for them (2.25" intake) and the installed height is 1.95". Standard retainers (Ti) and locks. I wonder why yours is only 1.98" with the retainers/locks you have???

Manley +.100 didn't give me near .100. Can't explain that. A block sonic tester will do heads.

It takes some work to get a Mopar big block valvetrain to work at 0.800 lift.

My advice is to buy one each of several different retainers and locks. Measure each of them and keep the numbers in a notebook. The mfg numbers cannot be trusted, you have to measure them yourself.

You should be able to find valve springs that will handle 0.800 lift at less than 2.100 installed height. Maybe 2.050 or even 2.00 if you look hard enough.

HI,Daytona540 i want to go in the same direction ,I also have 325 440-1....on my 572 if possible,please tell me what was the cost to open them up to 355...and did you go to 2.25 intake...thanks pat(was that done by cnc...?)

Manley valve spring P#221447 should work. Is .800 lift with or without lash? There will be deflection in the rocker also = loss of lift.

If you can't get the height with the retainers and locks,I suggest you use a thin hardened shim and not the .060 cups.

I had the same type problem last year. I found out that there is no standard in the industry on retainer height. I ended up with a set of Howards +.100 retainers, and +.050 Manley locks, and lashcaps. I had 4 different sets of retainers and 3 sets of keepers in my hands by the time it was done. You can try and call several different outfits and tell them what's going on and ask for 1 retainer from each one to see which one will do the job. Dave

I bought a single head last year, the spring retainer is actually higher than the valve stem tip. The head has 8mm stems, anyone ever see an 8mm stem and keepers in an 11/32" retainer? Thanks to wondering about this thread, I think that's what I got.
R.

I would call PAC valve spring CO. at 866-799-9417 and see if they have a set of valve springs, no matter which diameter, 1.625, 1.550, 1.525 or what ever will work for your heads at that installed hieght with the lift and pressures you need I would also look at buying thier matching tool steel 10 degree retainers and 10 degree keepers or the titianum retainers if the springs you select DON'T have inner dampeners

We have also thinned the cups from .060 to .030 without any problems in the past.