View Full Version : max lift on 452 head valve guides?

10-22-2013, 12:53 AM
whats the most lift that you can get away with without machining the valvguides down on 452 big block heads?? stock rocker arms, could i run a 509 purple shaft without machining the valve guides down?

10-23-2013, 01:32 PM
i'm talking about valve lift and causing the valve retainer to hit the valve guide requiring machining of the valve guide by cutting it down for clearance,,,, also does anyone know how much needs to be cut down?? i have a friend that works at an industrial machine shop and he could probably cut them down for free if i know how far down to cut them vs 350 dollars at the auto machine shop to do the same thing....

John Kunkel
10-23-2013, 02:34 PM
This is one of those jobs that doesn't require any exotic tools, you can measure the distance from the top of the guide to the installed retainer with calipers and determine if you have the needed clearance for the measured valve lift.

Trimming the top of the guide, if needed, can be done with a 1/2" drill and the items in the link below:



10-23-2013, 10:34 PM
Minimum retainer to guide clearance is 0.125"

So mock up a valve with a light spring and measure what you have for the lift your expecting to use.

10-27-2013, 06:47 PM
ok so heres my deal, i called 440source and talked to them and they said i should be good up to about a mid .550 lift before i have an issue, next question is what is max cam size that can be ran with stock rocker arms?? i was supposed to be getting a set of prepped heads with the guides cut and adjustable rockers and all but the guy got my money i had to spend on heads and i didn't get the heads, so now i'm at the point of trying to make things work with what i have. i have a lunati .494/ .513 lift, lunati says it should be good with stock rockers and all, but my thing is i really have more motor than what that cam calls for i got mid 10.5+ compression, 3500 stall, 3.91 gears in a dart, so i'm thinking sell the lunati and upgrade to something better suited to my setup, option 2 is to throw the lunati in with stock rockers and run it till i can eventually buy parts here aNd there for a upgraded valvetrain and cam spend a little here and there. does anybody have a set of adjustable rockers they wanna sell for good deal?? lol... also how much would need to be cut off?? or what is the max you can cut off the valve guides safely?? because if i can get it done by my buddy for free i'll go ahead and do it i just need to know to tell him don't cut them any shorter than xxx in height..... need to find a good deal on a cam suited for my application, valve springs and rockers, i have a set of springs for the lunati and another for a big solid roller....

10-31-2014, 07:06 PM
We ran the Mopar '509' cam with stock heavy duty rocker arms, 440-6V/hemi single springs w/dampers and stock style valve seals on stock 452 heads (and a few earlier heads) and this all worked, except when I later took the heads apart I noticed that all the seals had split, especially the intake valve seals. They were still around the valve stems, so not a big problem. I think the Lunati 0.494/0.513 cam would work with the stock parts, but a better choice would be the Comp Nostalgia grinds for the '484' (on a 383/400) and the '509' (on a 440),


10-31-2014, 07:12 PM
Also, we're running Lunati's .533/.552 Voodoo cam on a built 440 with the stock HD rockers arms and push rods (non-adjustable) on 440 Source heads with COMP 925 double springs and this also works fine. The 440 Source single springs w/dampers would also work great with this cam. An adjustable valve train is not required in our experience with the Voodoo cams or the Mopar "purple shafts". The COMP 925 springs require the small PC valve seals (since the clearance is tight from the inner spring). A modern big single spring (1.53-1.55" diameter) w/damper would be a simpler/better choice with aftermarket heads for any of the Lunati, Mopar or COMP hydraulic flat tappet cams, in my opinion,