Hi,
Does anybody know if I can cut the spring seats down about .100"-.125" of an inch on both the exhaust side and intake side in order to lessen my spring pressure? I checked the cross section pics in the archive but still not sure about that water jacket on the exhaust side. Intake side looks like I can do it. My heads are 587's cast in 73. Thanks

Weaker springs would be cheaper. How strong are your springs that you need to weaken them? If they are stock singles then you don't want to weaken them or you'll end up with bad valve float and kiss the pistons with the valves.

I'm using comp cams single beehive springs, I need to lose about 20-30 pounds. I was hoping somebody would know how much I could cut without hurting the heads. Thanks

just get a set of the comp 901-16 springs

drop on with stock seals with out R&R the heads

single with a damper

what spring rate are your springs?

Cutting ths seats down that much would greatly increase the chance getting to thin and breaking into the water. It really won't help your problem anyway because you should still use the recommended installed height.

Thanks for the help guys. Here is what I have-- right now I'm at 1.600 intalled height at 180lbs. I need to be about .100 taller to get about 150lbs. I assumed all this was just going to work, ya know, if a frog had wings... getting ready to call Comp and see what they say since they are the ones who helped me pick the parts, I'll keep you posted, keep all the replies coming, I need all the help I can get. If I get this worked out this week I'll have an engine to build this weekend.

That is only .020 less than 1/8 inch. That is alot of cut. I would remeasure. Standard recommended installed height is 1.68/1.70 so .100 would put you right in at the 1.70 installed height. IMO you have either mismeasured, or the valve are sitting too high on the seats, or you have shimmed the spring seats but even a standard valve will sit at close to the 1.68 mark. you shouldn't need any cutting to get the 1.70 measurment. Depending on the cam lift remember to check the retainer clearance between the guide/seal and the retainer at full valve lift.
PS: I have standard length valves installed at 1.8 but used a dished retainer to achieve the extra. There really isn't much extra meat in the spring seats.

What about running off-set keepers?

I installed stelite hard valve seats on the exhaust side so I can't cut down any more on the exhaust seats. Just got off the phone with Comp and they suggested the 616-16 +.50 keepers. So my machinist and I are leaning to using the 616-16 and cutting .050 off the spring seat. That will get us close. If you look at the cross cut sections on the engine archive it looks like we can cut on the intake spring seats but the exhaust seats look a little dicey. What do you think?

it would come down to how much material there is(in the seats) to work with but I think I'd try to get there with parts(you might check hughes's retainers) plus less machine shop labor bill EDIT if you do hit water or too close to it I have a pair of 587's you can have for free if you come up here to Nebraska & pick them up or $50 for my time if I wrap them & take them to the bus depot & send them collect.

Thanks for your help and the 587 offer. I think we are going with parts and a little off the spring seat. I was hoping somebody out there had precise experience with shaving a little off the spring seat. Let me ponder the 587 for 50, but don't wait on me if somebody else needs them.

I have a deal for you that you cant refuse. you have mail

what beehive springs are you using specifically? could you switch to PN 26986? at 1.6" IH you don't have a lot of room before coil bind with any spring....

another spring that MAY be a perfect spring for you are stock GM 3100-3400-3500 60 degree pushrod V6 springs. they're a beehive, have the same top dia as an LS1 spring and I think the comps, are ~360 lb/in rate, are ~1.94" free length, 1.065" coil bind height, and have a seat pressure of ~110 lb@1.6" IH

here's the data sheet from rockauto, and the cheap magnum spring thread from the "best of"