Thread: New heads. Valves are different between them

your machine shop said its good.....

if you dont trust them why did you take it there

Mind if I call ya SeaBiscuit..lol

Biscuit, I'm thinking either what you said or that they machined the seats.

The shop I took my heads to asked for the specs on the parts I was putting in. That's when I learned and asked about stock springs being 1.72X, with modded retaiers 1.78X and the spec for most aftermarket springs that we use is 1.800.

It was apparent to me why we kill dampeners faster with these other springs and modded retainers vs the specs on our stock springs. Say a 90lb spring is installed, the .02X means that it's not installed at a height that will give it 90lbs. As well if you are opening a valve as far as possible, you need to consider spring bind height and factor that .02x in because you are preloading.

I had my spring seats machined to ensure 1.800" install height of springs. Fresh valve job, magnafluxed, surface checked and paint job. They were already Stage 3 heads, no porting was needed. I like the shop because they are willing to talk and explain the few things I didn't understand. They also had a lot of work, from classic motors to the most current Subaru, Evo etc motors/parts. Even told me how Vtec and the oil pressure driven stuff works on those heads.

spring height of stockers can range from 1.690 to 1.750 depending on the shape of yours seats/valves

im not sure if we are on the same page, when i said 1.935 for tip lenght im not talkin about springs in any way, tip lenght affects lifter preload,

comp has springs that will do 1.7 IH
26981 110lbs @ 1.7 (347 spring rate)
26995 137lbs @ 1.7 (280 spring rate)Edit:could use these at 1.730 for less pressure)

or if you end up closer to 1.75
26915 105 @ 1.8 could mean 125 @1.75,

edit: most these springs Coilbind at 1.1 so even at a Ih of 1.7 you can safely run 550 lift

my brother has some ls covette springs i will be useing on a set of vortecs dont know the part no.
but it had 125 @ 1.7/ 325 @ 500 lift

vendor options are limited but a good machine shop should be able to give you what a guy needs

i try my hardest not to sink the valves for the spring install height, its dosent make sence performance wise to put the valve in a pocket. you will lose compresion and flow