built predator motor revisions

Hey guys I built a non hemi predator 212 last year it has a black mamba sr cam, billet lifters, cm pushrods, 26 lb springs, billet rod +.40, hemi flat top piston, rtc 6 head sanded down around .40 and ported by me (kinda overdid it), 24 mm carb and arc flywheel with built in advance. The motor runs great a little weaker on the low end but lots of top end. The revisions I wanted to do is try some stronger springs maybe 37 lbs to fix valve float, maybe sand the head some more for more compression, and get some better bolts for the side cover because my home depot bolts are coming loose from running it hard and leaking oil. What are your guys opinions on the springs ( what size , retainers?) , and what bolts should I get? Thanks


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No hardware store shims !!! And if you add shims you should have oil seals with out the rubber as a guide to keep them from walking . I find it hard to imagine that a mamba is floating a valve with 26# but we are talking thousandths shims . Watch for bind
I read on 4 cycle that the 26 lb white stipe spring like mine are a little short in the rtc 6 heads and that they are not a full 26 lbs with out shims. They recommended to some one else to use 1/8 or 1/16 machine washers. After taking off the head and valve springs and going to lowes I see that I am going to need actual valve shims because of the weird size with a big id and a little bigger od. Thanks guys
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I got six 10.9 grade bolts for the side cover and may use some split washers too. I'm waiting on my valves shims and gaskets from nr to put it back together. Thanks for the reply