Max valve spring lift on small block heads
April 6th, 2009, 12:54 AM
#1
Registered User
Thread Starter
Max valve spring lift on small block heads
Again, looking into my next project.
I'm thinking of buying a reman motor and swapping the cam and timing chain and thorwing all the other stuff on (alternator, p/s, etc).
I want to buy the Edelbrock top end kit from Jegs. It comes with the cam, manifold, lifters, and something else that I can't remember.
The cam's lifts are .496 on the intake and .520 on the exhaust. Can stock springs handle a .520 lift? I thought I read somewhere you could do a .540, but I also read Olds motors can only take a .500 lift.
Does anybody know this info
I'm thinking of buying a reman motor and swapping the cam and timing chain and thorwing all the other stuff on (alternator, p/s, etc).
I want to buy the Edelbrock top end kit from Jegs. It comes with the cam, manifold, lifters, and something else that I can't remember.
The cam's lifts are .496 on the intake and .520 on the exhaust. Can stock springs handle a .520 lift? I thought I read somewhere you could do a .540, but I also read Olds motors can only take a .500 lift.
Does anybody know this info
April 6th, 2009, 08:56 AM
#2
Registered User
Join Date: Mar 2008
Location: Phx, AZ
Posts: 1,012
WHY...
Good Springs are inexpensive, and essential for an aftermarket cam.
Get a remanned shortblock, and have your old 350 heads (#5's?), assembled for compatability with the cam you choose.
.520" is not too gawdawful for lift, but if you go more, it can bite you.
Not to mention, a good set of springs will keep it out of VALVE FLOAT when you wind it up.
Factory springs do not have enough seat pressure, nor, over the nose pressure for these higher lift cams.
Get an old Comp catalog, and start looking.
JMO
Jim
Good Springs are inexpensive, and essential for an aftermarket cam.
Get a remanned shortblock, and have your old 350 heads (#5's?), assembled for compatability with the cam you choose.
.520" is not too gawdawful for lift, but if you go more, it can bite you.
Not to mention, a good set of springs will keep it out of VALVE FLOAT when you wind it up.
Factory springs do not have enough seat pressure, nor, over the nose pressure for these higher lift cams.
Get an old Comp catalog, and start looking.
JMO
Jim
Last edited by Warhead; April 6th, 2009 at 09:01 AM.
April 7th, 2009, 04:22 PM
#4
Registered User
Join Date: Mar 2008
Location: Phx, AZ
Posts: 1,012
I understand the need to cut some corners, I just do not like cutting them on springs.
Since a stock #5 head has around a 1.7 inch installed height (1.67 to be exact), I would shoot for a set of Comp Cams 994 springs, or something equivalent. A set of Comp 743 retainers, and some 7 degree keepers would fill out the list.
ALL of the Cam companies have decent equipment here. You can do some bargain shopping if you want, just make sure that you get a valve spring with at least .660 inches of room, from installed height, to coil bind, for the .550 lift cam you want. Then get the retainers if it's a double spring (a damper is NOT a spring). You want at least 100 lbs of force seat pressure.
Jim
Since a stock #5 head has around a 1.7 inch installed height (1.67 to be exact), I would shoot for a set of Comp Cams 994 springs, or something equivalent. A set of Comp 743 retainers, and some 7 degree keepers would fill out the list.
ALL of the Cam companies have decent equipment here. You can do some bargain shopping if you want, just make sure that you get a valve spring with at least .660 inches of room, from installed height, to coil bind, for the .550 lift cam you want. Then get the retainers if it's a double spring (a damper is NOT a spring). You want at least 100 lbs of force seat pressure.
Jim
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