I've heard that vortec heads (l31) have really weak valve springs. I have a cam shaft with i think .444 lift or something close to that. Would i be able to use this cam shaft with the vortec heads?

Also, there is concern with the rocker arms? something about guide plates or not having them, and modifing the heads for screw in studs or something, i need help

 

Yes, factory Vortec valve springs are a no-go for any cam upgrade. One problem you'll find is the valve guide is large so the size spring you can fit over them is limited. Pretty easy to cut them down, but there are decent springs available the will fit over them. If you have the guides cut for positive-type valve stem seals, you'll get a better valve seal, and be able to chose better springs.

The rocker arms are known as "self aligning". Up until 1988, all SBC's (except aluminum and high performance) aligned the rockers with the pushrod hole in the head, which was really a precision slot. Starting in 1988, the factory made the pushrod hole larger and round, and put little nubs on the valve end of the rocker arms that went on either side of the valve stem tip - this kept the rocker aligned on the valve tip. It isn't really a problem as long as you use '88-later rocker arms and don't have too much lift, and .444" shouldn't be too much lift. If you buy new rocker arms, they need to be the self-aligning type. If you do guide plates, you can't use self-aligning rockers, and you need to remove the press-in rocker studs the factory used and have the heads machined & tapped for screw-in studs.

 

You can buy Z28 replacement valve springs. I cannot remember the part number off hand, but they are a replacement spring for a LT-1 350. I believe they can handle .550 lift. The spring has an inner dampener that you can pull out.

They will work just fine. This setup was recommended to me by a reputable mechanic and I've been running them just fine on my car for awhile.

 

Okay thanks guys, it helps a ton. So you think my camshaft won't be too much for the springs five7kid? the z28 replacement springs sound good, just in case that is, i'll try and look up some information on them

 

I was talking about the replacement springs with no inner spring that would fit over your large guides without machining.

That cam will be too much for stock Vortec springs.

 

oh darn, okay, i'll look for replacement springs then

 

I ran a .458" cam with stock Vortec springs and bent an exhaust valve over revving at about 6500 rpm.
I purchased Comp Cams beehive springs when I upgraded to 1.6 ratio rockers. Drop right in with no machining. No problems. I've since moved up to an XR276HR with lifts of .530" and .540". No problems with this combo either.

 

Stock Vortec valve springs are nothing special- very similar to earlier stock springs but without an inner dampener coil. That is to say, they are not for real performance use (exactly as Five7kid said). They simply lack the spring pressures you need to control even a mild performance cam in the upper RPMs.

So the real trick is to find a performance-capable valve spring that you can install without doing any machine work and reuse everything else you've already got. Performance on the cheap. Answer: good 'ol comp 981-16 springs. Been around for ages. Signifanctly stronger than stock springs but will install in their place with no machine work required. You reuse your stock retainers and locks, too.

The trick: you must remove the inner dampener coil. It simply won't clear the huge base of the stock Vortec valve guide. Same goes for "Z28 springs." They will get the same basic thing accomplished but you must remove the inner dampener coil first.

How to remove the inner dampener coil: stick your finger inside the spring, twist and pull. Out she comes.

I wouldn't recommend this unless I had done it (successfully) several times now myself. Easy upgrade to Vortecs with a mild performance cam for few dollars, and it's served well to 6300+ RPMs.

Yes, you can buy high tech beehive upgrade spring packages and build for even more lift and RPMs, but check out the cost on those suckers! Way beyond the cost of a set of old school Z28 or Comp 981 springs, and probably overkill for your application. You can also spend money on machine work to rework the valve guides, but that too costs extra money (and you STILL need better springs).

 

So would the 981-16 springs work with a XR269HR-12 and 1.6 rocker arms?
Valve Lift with Factory Rocker Arm Ratio: 0.495 int./0.503 exh. lift
Duration at 050 inch Lift: 218 int./224 exh.

I got a great deal on brand new vortecs and GM 1.6 roller rockers, so I figured I would throw a cam in while I was at it. I have a RamJet intake to top it off.

 

This article discusses the 986 spring and the beehive spring however the coil bind for the 981 is the same as the 986 according to Summit.
Comp recommends the 986 for the XR269HR.

http://www.carcraft.com/techarticles...ade/index.html

 

Yeah I would recommend just leaving the heads stock. They can handle up to .480" lift and flow well (for a factory head) right out of the box. You aren't really going to gain that much by having work done to them. You could take that money you spent on getting them worked on and spent it on a set of aluminum heads.

Get the replacement springs, pull out the damper and you'll be in business. I also recommend lapping the valves while you have the heads apart.

 

The only problem I see with the 986 spring is that the i.d. with the damper removed is too large for the guide boss and doesn't give a proper register for the spring. A 986 i.d. is 1.070". The guide boss is .900". That's over an 1/8 inch in the difference. Although it may be usable, I've never seen the application before. Tech articles don't recommend removing the damper to accomodate the head. Using the whole spring with the guide machined is the standard practise.