what is the max lift 041s can take without machining the guide plates and all? i know they can take at least .480 because that is what the stock cam was. i want to put in a roller cam and i want to go a little over .500 lift.

 

i don't believe there is any .480 lift stock cams. if you use a roller with the same, or even less lift you're still going to need larger springs and that'll require machining out the spring seats. also at .480 you shouldn't be running pull out studs. not sure what you mean or why you think you'd ever need to machine out the guide plates.

 

Be careful with these heads they have shallow spring pockets, Machine them to deep and you'll be looking for a new one.

 

the 69 z28 camaros had solid .480 lift cams.

 

very little more.

 

do you think i can get away with .502 exh lift? if not what will i have to do to the heads?

 

.46 or so is my limit for pull out studs. i'd trash the studs and get a screw in set and machine the spring pockets for larger springs. also i'd trash the factroy rotator set up and get aftermarket retainers ,but you would anyway since i'm sure you'll be running larger than stock spring diameter. you'd want to check for clearance issues with the valve guides and maybe machine the guides for positive seals.

 

Yeah I had that old .480" lift solid cam.... after I broke one good-quality 1.25" valve spring and pulled out the 2nd stud, I wised up and got screw-in studs and some 1.45" valve springs machined onto those heads. Porblem solved, permanently.

IMHO there's more to the "limit" of how much lift you can run, than merely the peak lift number (although that's certainly one of the not-to-exceed limits). The "intensity" of the cam, i.e. the steepness of the ramps, which is the measure of how bad it beats on the rest of the valve train, can make a cam to where even with seemingly OK peak lift, it's just too much force on all the other parts, and stuff starts to break.

Here's the page of Comp's catalog with their best street roller cams for carb motors. http://www.compcams.com/catalog/056_057.html Look at the XR264HR. That's a good cam for a smaller street motor with good heads. Note that even though the peak lift is less than .500", they recommend the 1.45" springs, because the cam will abuse the rest of the valve train so much. I'm running that cam in my 305 with ported double-hump heads and 1.6 rockers, with screw-in studs and 987 ( the next step up) valve springs; it's daily-driver reliable that way.

You've asked the same question about a million different ways in all your posts about this, and the answer is always going to come out the same. If you want to run a real aggressive cam, you need to put bigger valve springs and screw-in studs on your heads, even if the spec peak lift # would appear to work. That's all there is to it. Maybe somebody will tell you what you want to hear, but you'll be asking for trouble listening to it.

You just about can't put too much spring on a stock head, because of the way the head is made, they won't ever fit; so put the most spring you possibly can on it, do it right, and never have to worry about it again. Beats driving down the road or track and right at the worst possible time, having some part break, which will surely happen sooner or later with inadequate "just enough to squeek by" parts choices.