Hey guys,

I've got a new set of trick flow heads with the springs rated for cam lift of .520 max. I want to use the lt4 hot cam with .525 lift. I only need .005 more clearance. Anyone here heard of or used different retainers in order to gain extra clearence? I remember reading about this in a old issue of hot rod and I think I read they gained about .050 so that would be great. I would really apreciate some ideas.

 

Retainers don't matter in you situation. Springs get a lift rating because going past this rating causes the spring to bind. They do tend to under rate the rating a little for saftey through. I would get your current springs tested at a head shop for the max lift they can take. If not sdpc2000.com has springs for $40 that were originally on the vettes that had the hot cam.

 

Yes they do make different keepers, they move the groove in the keeper to change the installed height of the spring. But that is for something completely different. They do NOT change the amount of lift the spring can handle.

 

thanks guys, but I thought it was a retainer problem. What I'm talking about is the "plate" for lack of a better word on top of the spring that the keeps the spring in place, not the keepers them selves. I was under the impression that retainer hits the top of the valve guide and that is what limits the lift.

 

hey low c1500, I saw the springs you mentioned but I noticed that they were a bigger diameter than my stock shims, but I saw a set of hi po Z28 springs that are the same diameter as my current springs but can handle a .550 lift cam. Do you guys think that these could work for me?

 

The springs @ .550 sound good, but your heads may not take that lift. I am not an expert on stock heads, but I seen some posts in the past that say most stock heads can only take about .490 lift. This is because the bottom of the retainer hits the top of the valve seal. If your heads are off this distance can easilly be measured with vernear caliper. I did buy some retainers from sdpc2000 that gave me about .03 more travel, as the bottom of them didn't hang down as far as my stock ones. Find out what your heads can handle for lift, You might have to get the valve bosses cut down at a machine shop, they can make your heads handle .650 lift if you wanted. I would call summit and see if they make a retainer that allows for more lift, I think they have one. If you install the keepers that allow for more lift you would probably have install valve shims to get the correct installed height. My vortecs, with the new retainers ,measured out to give me .510 allowable lift before the retainer would hit the seal, my cam has .500 lift, and after only a day of being installed, and 6000 rpm, the seals got smashed , I a puff blue on startup . So now I have to pull the heads off an get the bosses cut down. This I what I strongly suggest you do as well. You can buy a tool for the job for about $50 from summit, or the machine shop should do it for under a hundred, this would allow for stock retainers and keepers.

 

I'm a machinist by trade but I haven't done any automotive type machine work. I'll give trick flows tech line a call tomorrow and see what they say. If I'm lucky I can just pop for the springs and retainers.

 

Sorry, I missed the fact that you had trick flows, I thought they were stock heads. Those heads should be able to handle .550 +.

 

Or you can just use 1.5 rockers for now , the .525 lift is with 1.6 rocker arms.

 

hey evil t/a,

Do you know the specs of that cam with 1.5s? That the ratio of the rollers I have right now.

low c1500, Yeah I've got trick flows. That was kinda the problem. I don't know much about aluminum heads but I thought if they used the same castings for all their heads then just switching vavle springs and retainers would get me back in the game.

 

Its .492 with 1.5 rocker arms.

 

It should, I love my springs and retainers from sdpc2000, plus they were dirt cheap, I think the light weight vette retainers were only $29. They give you a little more clearence. Your heads should work fine with the 1.5s. Did you ask trick flow about the heads?

 

I bought brand new 23 degree Trick Flows, with the 1.25" springs, about a year ago. Had a .495/.502 lift hydraulic roller cam and had never turned it over 5000, (at that time). The top round broke off of one of the springs. Caught it before it did any damage. I couldn't trust them springs so I replaced them all. I bought aftermarket springs and installed them to 1.750 with all the other TFS parts. Have turned many 6k runs since.

I emailed TFS and they said they'd cut me a deal on some larger springs and hardware but I never got back to them. Think I'll do it tomorrow though and see what they say.

Good luck but I wouldn't push it. Dropped valves can make a real mess.

 

Well I talked to tfs today and they said that the guide would not be a problem. As long as the installed height is correct and the springs can handle the lift. I saw a set of heavy duty Z28 springs on sdpc2000s site for $49.00. I'm going to call them tomorrow and see about getting a set along with the cam. Thanks for the help guys!

 

by the way smasterson,

What springs did you use? Also did you reuse all the other parts that came with the heads? The spring seats and retainers? or did you need thinner spring seats?

 

I have the vette retainers (their $13), there great I would suggest you uses them over the stock.