I plan to buy new LT4 heads. (I am aware that I can port LT1 heads but I would rather port these LT4's at a later date.) Who makes a drop in replacemet spring (no machining, no additional spring locator, no additional valve stem seals) I want to use all the NEW hardware that comes WITH the new heads, just simply change the valve springs.
I am considering either a Comp Cam 306, or XE 224/230, or XE 230/236. So lift should stay under .600.
I have not decided what rockers to use but I already have a set of used Cam Dynamics 1.6 non-self aligning available.

Crane? Isky? Comp Cams? Who makes a spring for this application? Part #'s?
Has anyone tried the CMotorsports springs yet?

 

It should work on an LT4 too, dont see why not. Combo just came out with one. Check out their website, or search for all threads started by combinationmotorsports. Its cheap and works very well seems like.

 

I read the cmotorsports posts and didnt read about anyone who has actually ran them. I guess you guys must be getting info on their package deal via email because their website doesnt give any info.

Does anybody know if Crane, Isky, or Comp Cams has a spring like I specified above?

 

You could use comp 987's the 987 seats are oversized for the springs by quite a bit. My friend and i put on 1.6 RR's on his car and all he had to do was grind a little relief on one corner of the seats so they would drop on and the spring sat right and worked perfectly. That was close to a month ago no problems yet.

 

You might give Comp a call and see what they say but a 941 or 983 MIGHT possibly work. These are single springs and might not last as long as a dual spring (987, 986, etc) but they would drop right in other than removing the damper since it might cut into the stock locator. A Comp 987 would be the best spring but would require machining and some Comp 4771 locators. I would suggest giving them a call if you want a Comp spring to work with stock retainer/ locator and see what they recomend.

I know TPIS offers a spring but not sure how much $ and it could VERY WELL be a Comp spring with the part # removed from the box. (LOL)

Cmotorsports is supposed to have a spring/retainer kit for like $90 I think. You might check with them about machining and/or using stock locators. Not sure about the quality but the price is right and with your light valves you should not have a problem.

Since you do have light weight valves you can get a way with a little less spring pressure than normal. Not that I would set them up at a lighter pressure but under the same circumstances you will float the valves or experience spring problems at a higher rpm as compared to a heavier Manley or Ferrea valve.

The main thing to check would be if they work with stock locators. If not make sure that you get the proper locator that will keep the spring in one place instead of just a hardened shim with a large hole in the center that can (and will) move around and possibly cause valve float, pre-mature spring failure or destroying the valve guide seals. I used to think that they did not move around much but after inspecting some heads that have had dual springs with no locators I have found how important they are and now I recommend them to everyone. Destroyed seals and signs of walking around as well as valve float at high rpm with correctly set up spring heights are a few of the problems. Make sure that the spring is on a locator that fits snugly aroung the guide and will not move.

NightTrain66