Is there an upgrade valve spring for these heads that use the stock retainers and locks and require no machining"
All the posts I can find on the subject are "maybe" "should" or "try"If someone actually has made this upgrade the brand and part number would be appreciated.
Thanks and have a Happy New Year

I have built a mess of them there magnums and never come across any upgrade spring using the stock retainers. The closest thing I have found for a cheap simple upgrade is the GM 3100 springs and retainers, they give just a little more pressure with a little lighter retainer for a nice overall upgrade that will work with mild cam upgrades. I have also shimmed the stock springs for very mild upgrades or just when I want to turn a stock cam higher RPM because I got rid of the beer barrel intake for something more performance oriented, they tend to be happy turning another 500 RPM with any better intake.

Google............
LA confidential mopar
That article is about an enginemasters 318 magnum build. Lists part numbers, etc, etc.
Might help ya out with ideas
I bought the motor, ran superbly.......to 6500 rpm

http://www.hughesengines.com/Index/produ...mp;partid=30450

kit includes springs..retainer and locks...say no machining needed .550 lift coil bind @ .620.

Not sure about top of guide clearance.