I can't read?? Read your own link jack-azz!! 8005 plus, As I said, 1.875, 135-140psi, maybe you need a refresher reading comprehension class along with a Engine builders course. I was not looking for a pissing contest either, just stating something I most certainly know, and your dying to prove sombody wrong, on something you obviously know nothing about.

When it come to the stock 500's, which is where this started guys, you are both somewhat off. And I'm the one that is right on with the specs, and spring choice for the application in question.

Oh...so now they are the Plus...Change your mind again?

Why would you run less spring pressure then Merc uses?

The Compcams 929 have a seat pressure of 148 @1.880 your recomendation is to go to a 135-140. Sure why not.




I'm done....
Dave

Change my mind?? As soon as i figure out how to post the info from MY ISKY cat. I will. 150psi is too much countinous pressure for a Hyd. roller, bar none. Merc. specified this do to the springs the factory installed, they would relax to about 120psi after minimal usage. But I guess you would not know, becuase obviously you have never been hands on in one to really tell. I don't give a **** if the pope says to run 150psi, thats too much constant pressure on a hyd. cam. Hell, we ran 150psi on +.700 lift soild rollers back in the seventies, when 150psi WAS a big spring. I have even rolled our own springs, buying Chrome-silicon wire, from D&S wire, back when they were still in Linden NJ about a million years ago. So, believe me, I'm not some 18yr. old jack-off on here speaking of **** I don't know a little about. I guess this is why I never embraced the computer internet age too well, just trying to help, but this is too intense, I guess i'll leave the Q&A's to experts like yourself. Bye, Mark

What's wrong with mine?

So someone has been able to calculate the loss of spring pressure, well let's say "after minimal usage". Another wonder of the world. Good for you, dig that hole deeper! I'll look for that in the Merc TSB's...It's gotta be there if you say so.

I have had my hands in many motors, never claimed to be an expert. Just sharing an opinion...

Dave

Here's some more of my opinion...Follow the link to Crane's website for a cam similar to the 500efi

Crane

Pay special attention to the required spring pressures!

Anything else?

Dave

Very easily calculated! Sh*t, back when we used to run blown gas in the flatbottom, the best springs we could get was right at 180psi. After 2 or 3 hard runs, or dyno pulls, whatever, we would pull the heads and immediatly the springs would have relaxed to 150psi! So yeah, for that Donovan spring, i could calculate about a 25-30psi loss after spring break in. But your the expert, keep going by your merc. book. I suppose for anyone that wants to run a competitve pro-stocker should go by a General Motors service manual too. Like i said, I will post my spring page from my cat. just to make a point. Not trying to dig a hole, just trying to dig in your azz a little for busting my balls.

Aren't we talking Boat engines?

Still living in the old days...Things have changed, It's going to be 2008 soon...Not 1972!

BTW, You must have a special Isky catalog (Also from 1972)

Dave

I wish i was friend, i really wish i was. Yes, a flatbottom is a boat, along with a pro-stocker, modified and super eliminator, and a dozen other classes. Yes drag boats, which were my specialty years ago, but now i mess with guys like you. I'm trying to post some info from both Isky and Crane sites, one on spring pressure and the other with part number discriptions. I have saved them, but when I try to upload them, the site is saying invaild file. Maybe you can enlighten on how to do this, as I admit, my computer skills are low, but hey in 1979 the computer on my Mori-Sieki Mill only held one program at a time!
Mark

We are talking STOCK 500efi here that turn 5350 rpms, not super modified Drag boats. What info do you want to post?

Dave