Well my motor decided for me, that it was time for the new cam. I was coming home the other day and it started ticking. I pulled the valve cover off and I have a bad lifter.

So, I have a few questions..........:bow:

What installed height and seat pressure should I shoot for on my springs?
Do I just go by the paperwork I got with them? I also have +.050 retainers, thats why I am wondering how critical this is. I would think coil bind would be the main issue of concern.

Should I break the cam in on the OE springs and swap them out afterwards?
Both OE and the cranes are single with a damper.

I have 3/8" pushrods but 5/16" guideplates can I get by with opening up the slot with a cutoff wheel?
With the guideplate in the vice of course, not on the motor. I will buy new ones if I absolutely have to.

Do I install the cam straight up? My cam has 2* advance ground into the design. Its 230 @ .050 with .544 lift LSA/ICL=109/107
It's a stock 72 402 with shim head gaskets. I calculated compression to be about 9.07. It's got 3.55 gears and a 4 speed.

I want to replace the valve seals while I'm there. Any suggestions??
They don't have to last forever since the motor is 36 years old already, but they need to seal. Should I just go with OE type seals?


The motor runs good and I want it to last a couple years untill I collect enough parts to build a different one. Thanks in advance for the help! This site has helped me tremendously since my Dad passed away, along with all his knowledge about this stuff.

guideplates are about the cheapest thing in an engine. they're also case-hardened and you won't like what you end up with after the cut-off wheel deal. Why can't you re-use your existing pushrods

>> What installed height and seat pressure should I shoot for on my springs?

set the springs up at the installed height and pressure spec'd, hopefully this is what the cam calls for. Did you buy the right springs for the cam?

>> Should I break the cam in on the OE springs and swap them out afterwards? Not unless you're sure the old springs can take the lift of the new cam. if they coil bind your new cam is toast.

Go with OE type seals, others may require machining of the top of the valve guide, not something you'll be wanting to tackle if you're thinking it's OK to hack up the guideplates with a cutoff wheel.

Do not cut the guide plates - replace them to match your new hardened pushrods. The rate of hardness between todays pushrod/guideplate combos is different than years gone buy.
Make sure you check valve seal clearance up against wide open on you cam - with .544 I think your getting close to trimming the top of the guides for extra clearance.

guideplates are about the cheapest thing in an engine. they're also case-hardened and you won't like what you end up with after the cut-off wheel deal. Why can't you re-use your existing pushrods

Did you buy the right springs for the cam?

Go with OE type seals, others may require machining of the top of the valve guide, not something you'll be wanting to tackle if you're thinking it's OK to hack up the guideplates with a cutoff wheel.

I'm not dumb, I'm just broke.;) I do have access to a mill for the seals but the heads are not coming off. I bought 3/8" pushrods after searching posts and finding that 5/16" pushrods won't handle much above stock mods. Is this true? I kinda had a brainfart and didn't think about the guideplates. I guess mufflers will have to wait.

I had summit choose the spring for me when I bought the cam. The springs lunati recommends are exactly the same except for the spring rate. Lunati's are 342 lbs/in and the crane's I got are 354 lbs/in. I think the stiffer spring rate will help with the valve float issues, I have read about with the recommended lunati springs. I have a VS height mic so I will be checking clearances before I install.

Is .060" minimum coil bind clearance, and is .060" enough for retainer to guide clearance?

Lastly, Do I install the cam straight up? My cam has 2* advance ground into the design. Its 230 @ .050 with .544 lift LSA/ICL=109/107
It's a stock 72 402 with shim head gaskets. I calculated compression to be about 9.07. It's got 3.55 gears and a 4 speed. Do I need to advance it more, less, or leave it alone?


I will add guideplates and OE umbrella seals to the shopping list, unless the 5/16" pushods are fine to re-use? Are comp cams guideplates OK for heat treated, heavy wall pushrods.