what valve springs for GT40 or Ps

[1990LTD]

I don't know if both of 'em came with crap valve springs or not but what are the recommended replacement valve springs for these heads? Does it make a difference? Is a spring a spring? how about retainers/keepers?

[Crownvicman289]

I believe you can find your answer at corral.net in the 5.0/5.8 Windsor section. Look in the GT40P sticky and start clicking. P heads use weird valve springs and weird retainers and crap stock springs.

[BerniniCaCO3]

From what I understand it really depends on what you want to do with your build... A high lift, and actually more relevant than lift, a steeply ramping camshaft requires a stiff spring to keep that lifter glued to the camshaft.
High rpms on any camshaft require the same thing, and larger ratio rockers will also compress the spring more, possibly requiring a stiffer spring to return quickly enough to not "float."

On the other hand, the energy put into compressing stiff springs is largely not recoverable. Very stiff springs hurt fuel economy. If it's a daily driver for the highway, stock springs should do you just fine.
But of course, it doesn't hurt to check out the springs that are already on your heads and if they're still any good. If they've got serious miles on them, pay a few dollars to just replace them.

I just measured the springs on some very dirty, 20yr old, but supposedly only 60k mile e7te heads; the springs all measured out just fine, actually a good 20 lbs stiffer than required spec.
At the other end, I have an instructor who races very seriously, and he replaces his springs every couple hundred laps (however far a lap is)... but it can't be that many miles at all. Some very aggressive camshafts and high rpms being run on very stiff springs.

[BerniniCaCO3]

so for me, I'm leaving the original springs on the e7te heads... and on the gt40 heads going on my own car, I've got some stock replacement springs from comp cam, well, just because; it's my "baby" and I don't want to have to open this engine up ever again, I like to be a perfectionist when I can afford it.
Saw no reason for performance springs....

[86VickyLX]

Performance springs are good for the future. They are not necessary for stock cam applications. Stock valve springs would work just fine. On both GT40, and P heads. GT40Ps use the same valve springs as earlier models. Granted, when putting a new engine together, I wouldn't recommend reusing valve springs, just on the basis that, those springs had been sitting in a compressed state for who knows how long. Leaving them compressed can cause them to lose their spring strength and make them weaker, making them more prone to allowing the valves to float. Also, if the valve guides are worn out in the head, the spring could be bent because of a pull towards one side vs another. A valve job and new valve guides (I personally like bronze liners) will correct this problem. Also note, that if the springs are messed up, the valves might be as well. If the heads are coming apart, you might as well check the valves to see if they're bent, damaged etc.

All this stuff could prematurely wear out new valve springs, so be sure to check all of that stuff out first, before you put new valve springs on.

[1990LTD]

479 lift

[zoomie]

479 lift

replace those springs mang, youll be better off, and everyone that i know who has a set of those heads gt40 or p heads replaces the springs . stock springs arnt all that great especially if yoru using an aftermarket cam.

[1980c10]

Yea I'm pretty sure a H.O. Cam will float the stock explorer springs.

[1987cp]

You buy springs to match your cam and intended usage. End of story.

[Crownvicman289]

Yea I'm pretty sure a H.O. Cam will float the stock explorer springs.

Thank you, this is why the P springs are junk. With an uncorked GT40P setup, even with a stock Explorer cam, you should definitely change those springs. I'm going to take a whack at lightly porting my heads while I'm at it and also replace the valve seals.

[Mercracer]

As was mentioned, the stock springs are barely adequate for the stock cam. Before a new cam goes in, the heads should get cam(and future cam) appropriate and a high quality springs, retainers and keepers....