Ok, i just recently got a 350HO, its sitting on the engine stand right, and im about 2 weeks from putting it in, and haven't decided if i want to cam the bad boy or not.

Now the LT4 cam seems pretty tempting, but from what i understand you need to pull the heads to have them machined to accept a larger diameter valve spring.

But there are vavle springs from what i see that are still the stock 1.250" valve spring dia. and support more lift, such as these,

http://www.sdpc2000.com/cart.asp?act...2060&pid=81626

Now i know that the L31 vortec heads have pressed in 3/8" studs, but are screwed-in studs absolutly nessecary?

what im getting at is, with the sprigns above, can i install the LT4 hot cam safely?

 

No.

There are other problems besides the springs. Specifically, on those heads (Vortecs), there is only enough clearance between the bottom of the retainer and the top of the valve guide to accomodate about .460" of valve lift safely. Machine work is required to go very far at all past that.

But, those GM springs are inadequate. I would not trust any 1.25" OD valve springs at above .500" of lift. Notice that none (that's non, as in exactly zero) of the cam mfrs, who will warranty your cam if it wipes out, will honor a cam warranty if the lift is above .500" and you used any 1.25" springs. Numerous people on these boards, over the years, have had trouble with the HOT cam kit and valve train destruction. GM won't warranty that cam, period.