Motor is a stock 90 Mercruiser 350 sbc with 083 heads. Motor has 150 some hours on it. Cam in there now is 200/204 398/403 110 flat tappet. Looking to putting in roller 214/220 and mid 460 lift. I am upgrading to the roller because I have all the roller stuff in the garage. Just wondering if the stock springs will handle 465 lift. I figure in car miles these springs dont have over 20K.

 

No. They are garbage.

 

Stock springs can easily handle .500" lift (even thought stock heads won't take that much before you slam the retainers into the guides) BUT BUT BUT..... in all cases they don't have sufficient seat pressure or spring rate to handle even a mild performance cam (they are marginal even with a stock cam).

Now, you don't need to spend megabucks to upgrade. For mild stock-ish roller cams I've had excellent results with dirt-cheap Comp 981 springs. They're really springs for mild to modest performance flat tappet cams but they also work well for mild rollers becuase they have significantly more seat pressure and spring rates over stock. I like them for applications such as you are considering becuase they are DROP-IN replacements for stock. NO machining required whatsoever. Remove your stock springs, install the 981s with all the stock hardware again and you're good to go. Comp rates them for up to .480" lift so your .465" lift cam will be no problem.

 

should spend the 70 bcuks or so and get fresh springs... stock heads i've read have clearance problems at .470-.480 lift but double check that to be sure with a micrometer.