Okay, so I'm going to get myself a ZZ4 Roller cam this week off of ebay. I'm a little concerened because the L98 heads I have were fitted with Z28 valve springs. Will those springs be able to handle the cam? This is what I have on the cam:

Part # 10185071 Duration @ 0.050" Lift: 208/221 Lift: .474"/.510" Lobe Separation: 112 Type: Hydraulic roller tappet

If I have to change valve springs I will, if not then I'll save myself the money. I just want to know for sure.

 

which exact springs do you have, there are several 'z/28' valve springs. if you know the seat and open pressures, along with coil bind point, that would be helpfull with .510 lift, if you plan to run 1.6 rockers, i would go with larger 1.5" springs instead of the stock 1.25" style springs, that will require you to have the spring pockets opened up by a machine shop.

IMHO changing springs with a cam is worth it, it is cheap insurance. you do not want to see what you piston will look like if a spring fails, and a valve hits something, it isn't pretty.

 

Well I got the heads off of ebay and the guy that sold them to me said that they were fitted with Z28 valve springs (three angle calve job, mild pocket porting) and, at the time, I figured that's all I needed to know. Is there a serial number I could look for? On the springs that is.

I mean, the heads are in excellent shape. The valves and combustion chambers are clean. He had them on a rebuilt L98 that he had in a hot rod he ran for a few months (and miles) before he decided to go with an LT1. Knowing that, I figured they'd be the good ones.

I am planning on going with 1.6 rockers so that's why I was wondering if I'd have to switch to different springs. How much does it usually run to have a machine shop do that (swap springs)? Thanks for the input.

 

swapping springs is easy if you have a compressor, if not i doube a shop would charge much, i can pull springs on a pair of heads in about 10minutes. since you are planning on runnint 1.6 you are looking at .544 lift on the exaust side, with that much lift you are going to want to run a 1.5" spring for sure. i would guess a shop could pull the springs, machine the seats, and install the new springs for $100 or less. you will have to call around your area though, prices can be very diffrent depending on where you live.

 

i ran the SLP 495/510 on stock springs for 2years 87 iroc newer,stiffer springs would be a benefit though especially if you plan to use 1.6 rockers!

 

you have to check the coil bind, i would guess that stock springs would bind before .544

also, the larger diameter spring puts less pressure on the coils, because there is more wire per coil. it is a better option if you are planning on building a hi-po engine, build a hi-po engine. things like springs are part of the game. really new springs are cheap insurance for your engine.

$80 for springs
$800 for a rebuild and new pistons.