Considering a cam change to more lift, that will warrant a spring height change, that will warrant a +050 lock, that will put the retainer pretty close to the T&D rocker setup I am running. Been there done that and don't like it. Usually aluminum in the oil filter from the retainers clearancing themselves is the result.

Anyways, my heads are set up with .060 PAC spring locators right now to get me to 1.950.

Naturally, PAC doesn't offer anything thinner, so I am machining something off at the seat to get there I am afraid.

What I am considering is taking some off the spring locators and some off the seats. Maybe .020 off the locators that should require .030 off the seats.

Anyone done something like that? Safe?

I have .030 spring cups for my PAC triples. So somebody out there may have them in your size? I also used +.100 retainers and +.050 locks to end up at 2.070 on the intakes, heads uncut.

Were the seats cut for the locators? If so then you might be at the limit. If not then you can probably safely remove .060.

I think machining the locators would be risky and they'd have a tendency to crack and chip.

Can't you find a stiffer spring with the same installed height that will handle that new lift? A triple spring maybe?

My -1's run Pac 1224 (1.625 dia.) springs at 1.950" with Pac locators that are .060 thick? I did skim cut some of the pockets to gain clearance. It has paired T&D 1.7 rockers. No clearance issues to the retainers. The heads were used when I bought them 13 years ago. Made over 1000 passes since.
Doug

I have .030 spring cups for my PAC triples. So somebody out there may have them in your size? I also used +.100 retainers and +.050 locks to end up at 2.070 on the intakes, heads uncut.

It took some time trying different parts but I was able to get right at 2.100 installed height on my Indy EZ heads. I had to mix and match retainers and locks. I discovered that different brands measured things differently and that you couldn't trust the mfg specs.

It's not the spring pressure the 424 R should be plenty enough. Its 656lbs/in. It's the installed height to get my coil bind where I need it if I go in the upper .700s lift. I did some checking here tonight and a few of them are actually closer to 1.940, which puts me at .086 from coil bind. These springs have 1.14 coil bind. I would like lift somewhere in the upper .700s if I can get it. Talked to Tim at Bullet the other day and he said .768 (honestly I would like a little more) which would put me at .032 CB so I have to find some spring height somewhere unless I change everything.



DW have you ever measured how close the retainers are to the rockers? I run bushed T&D, maybe different? With my R405 retainers and +050 locks I can get 2 pieces of thick paper between them that measure .020 total. Feels like it might be .025 or so? I don't think I could fit a 1.625 spring on it. The DR425R is 1.525 and the R405 retainer is 1.450. Its a nice setup if I can get some more installed height.



I have cups. And naturally they are .060 lol.

I run a dual spring and I always like the ID locators that fit the inner to keep everything centered. If I ran cups on these springs the inner would be centered only by the spring itself. Don't like that.

I need to call PSI tomorrow and see what locators they know of that will work with these springs. All I seem to see are the PAC S104. Its 1.55 .770 .635.



Oh great! So I might order something expecting it to work and it won't.

On a side note, why is everything with locks and retainers in increments of .050? Seems to me .025 would be better so guys like me don't end up in installed height lala land.

When I was sorting this stuff out I ordered a bunch of single retainers rather than full sets. I built a spreadsheet that kept track of all of the information. I'll attach a copy.

Andy, what is the last column(tool) referencing?

Here is a picture of the retainer measuring tool that I made. I found that retainers from different mfgs had different installed heights. There isn't a spec for retainers so I made a tool with a 10 degree taper that allows me to measure the different retainers.

We have standardized the spring retainer “cone style” to improve specifying the fitment
into a matching PAC Racing retainer.