in general what are the stock magnum springs good for?

I have a stock LA id love to swap mag heads on, but i also have a 270/470 comp cam id love to install in the future.

There needs to be a complete tech right up on lift, and flow of the stock heads as well as whats needed for the conversion.

Mopar Action has a great write on on Mag heads Vs chevy.

cheap magnum spring thread about gm 3100 springs

if you read through this, you'll find most of the pertinent info. with your current mag spring IH, you're probably right on the edge of allowable if you swapped to the GM springs (you'd be looking at probably .045" clearance to coil bind when calculating it out). stock mag springs are ~240lb/in with less than 80 lb seat pressure, the GM ones are ~330-365 lb/in with about 90-110lb seat pressure with what you'd probably probably see for an installed height, which I'm guessing would be ~1.61" or so.

Also considering the bad small block pushrod geometry he should have a bit more than the .045 to coil bind.

The dealer charged me $125 for my last set of 16 springs and 16 retainers. I don't remember the individual prices but that is quite a bit less than the $10 a piece, that would be over $160 just in springs plus you would still need retainers.

u think id need retainers

Hughes has springs that will work, under $6 each. A set of retainers is $62. Thats $154 for the set and the springs don't coil bind until ".620 of lift, much more most people will ever need.