WIll the stock valve springs work with the crane 274 energizer cam? The lift is only .450 and the rpm range is relatively low. The motor is a gm 290hp crate motor.

274 cam calls for closed seat pressure of 107# @ 1.800 installed height and about 270# open @ 1.370... I would definately check to see what your stock springs to those specs. I would also check for coil bind @ full open height . Need to verify you are not stacking out spring retainer also against valve guide boss. Don't assume anything . Just do some home work here.

Heck, for no more than $25 to $35 or so, you can buy either Z-28 or the later, LT-1 valve springs and not worry about it.

pdq67

Heck, for no more than $25 to $35 or so, you can buy either Z-28 or the later, LT-1 valve springs and not worry about it.

pdq67

The Z/28 ("30-30" cam) and the LT-1 both used the same #3911068 80#/200# springs as all the hydraulic-lifter engines did; the only one that was different was the #3927142 Z/28 "Heavy-Duty" spring that was released only for use with the -140 cam. :thumbsup:

The Z/28 ("30-30" cam) and the LT-1 both used the same #3911068 80#/200# springs as all the hydraulic-lifter engines did; the only one that was different was the #3927142 Z/28 "Heavy-Duty" spring that was released only for use with the -140 cam. :thumbsup:

Last note I have on spring pressures on the -142 spring were 110# @ 1.700 and 260# @ 1.250...Taken from Chev Spec Equipt manual 3-9-1972.

I have ran two 274HO6 cams with stock springs and had no problems.

Ditto!

It's not all that aggressive a cam.

John, I'm going with what places like Competition Products spec's both the Z-28 and LT-1 springs at here b/c places sell them with slightly different spec's, prices and PN's.

pdq67

It sounds like the stock spring will not have a coil bind situation so the only danger with a stock spring will be valve float, correct? This is a cast piston motor that will be limited to 5,000 rpm max. To be used for street and autocross. Probably never see a drag strip. I was thinking about the Crane Blue Racer springs in Jegs catalog.

And John, I'm calling the Z-28 springs the -142 jobbers here..

pdq67

I think you guys are mainly interested in the Z28 springs but something that I have run across is the new beehive springs. They are low tension but control valve float well, according to what I am reading. I think it does require a differant spring retainer but it is a better spring with lighter pressures. Just .02 here.