does anyone know what the maxumum lift the stock valve springs can take?

 

This may help:

Vin 8 and 7, Valve Spring Dimensions
Free Length 1st step 2.03 in
Damper Spring 1.86 in
Installed Height Intake 1.7187 in
Exhaust 1.5937 in
Seated Pressuure 76-84 lbf at 1.7 in
Compression Pressure 194-206 lbf at 1.25 in

I'de say they are good for .470"-.480" lift.

 

In most cases they'll actually take about .500" becuase they use a rather small diameter wire (ususally more than the stock head itself will take before retainer-to-guide interference happens). Unfortunately, that also means they don't have enough tension to control a performance cam that would lift them anywhere near that high.

 

thanks for all the help, i thought it was somewhere around .480-.5. that will be more than enough for my new cam. its the TPIS flat tappet cam.

@.05 lift 221/230 and .454/.454 lift. it should be a good match for my stock headed motor. that along with my new runners and ported base should make this thing haul aZZ. iam hoping for mid to high 13s, i think she should get there.

 

have you ever heard of anyone haveing problems wiyh a cam that big with the stock springs? by the way their from a 85 L98 there still preaty new so i dont need to replace them if i dont have to. i was also looking at a crane Z cam it has 218/230 and .459/486 lift (both cams have 112lsa) both will give very similar resualts, but i think that the lift on the Z cam maybe too much.

 

most i have head ppl running on stock heads is .480 and i think some one has stated they are using the Lt4 hotcam on stock heads/springs with the 1.5 rockers...which is .492 lift.

i wouldnt recommend that

 

what about the Z cam i talked about in the post above. iam thinking that i should just go with the TPIS cam and keep it safe.

 

They'll physically take the lift, but valve float can occur at frighteningly low RPMs. Stock springs were barely adequate for the stock cam up to 5000 RPMs.

A set of Comp 981 springs are true drop-in replacements for stock and will control a mild performance cam MUCH better than stock springs will. A set of cheap "Z-28" springs off the internet will work, too, for less money.

 

sweet, thanks for the help. i might get those springs.

 

Don't forget the valve seals. Check them for clearance.