OK, I'm going to change the present valve springs I have that apparently have to much seat pressure(145#)in my 454. Since 2 of the 3 cams I've run with them went flat I've got to assume this is a problem.

At this point I prefer to err on the side of a little less spring pressure than too much.

So, for a Lunati/UD, 280/288 with 525/550 lift what springs do I need? Preferably something on the conservative side. I need the brand and part number.

Thanks!

Harold told me he likes them with about 110 at the seat, with a max of 120 lbs.

Bill

If I were you I'd buy the springs Harold recommends for the cam. Then, make sure the machine shop sets the springs up at the correct height to get the right seat pressure and eliminate coil binding. You may also want to check closely for binding or other interference issues in the valvetrain. Retainers hitting the valve guides seems to popular lately. smile.gif There must be more room between the retainers and guides than there is lift plus a little safety margin. See it with your own eyes before putting the heads on..

Tom

James,
Just located Mr 4 speeds old post. He used Cranes 13308-1 single springs. Same ones I am using. Hope this helps. He had spoken with Harold about them before and he said they would be fine

For the record, Crane's new website stinks.

what i did for choosing the correct springs was flip through comp, crane and crower's spring catalogs after finding what my installed height was going to be. I looked at the different recommended installed heights, coil bind, and pressure on the seat and open pressures.

Can be a little confusing, but you'll narrow it down pretty quick.

I used the GM 454-502 HO springs with my .550 (gross) lift Lunati. Good for .560 max lift and have 110# seat pressure at 1.88 installed height. Very similar to the stock LS-6 spring. They are a dual spring and I removed the inners for break in. Available cheap at Competition Products.

BTW, those springs are also called " L88" springs and are currently available at www.competitionproducts.com (http://www.competitionproducts.com) for like $40. If I didnt have a set of COMP 924s on the shelf, I'd buy a spare. MC71454 ( Tom) sells complete kits for around $105.

Brain, exactly why I put my comment on Crane up. With the new website, you can't get spring data, at least not easily. They had some newer 1.46" spring designs that would work for my cam, which I now can't find the tech data on. Sent them an email as well. Maybe I just couldn't find the tech data.

James, here, the Hi-Perf duals. Make sure your single retainers can work with them. The GM retainser have an inner step for the inner spring to locate on. And also, break-in the cam ON OUTERS ONLY. You can run it around on outers for a bit as long as the revs stay below 3500. I put maybe 3+ hours of run-time on the outers, just to be safe although Harold said it wouldn't really be helpful, first 1/2 is all that's required.

The Lisle hand held spring compressor available at PepBoys is the ticket for the spring R&R.

http://www.competitionproducts.com/page27.html

I have the 280/288 cam and I only run a single spring. I only spin it to 6k and I have not had any issues so far.

Originally posted by 427L88:
For the record, Crane's new website stinks. I second that.

Well, I'm going with the Cranes.

They are a little low on the seat pressures but at this point I don't have a problem with that at all!!! The installed height is close to what the springs I have now are so that could save me some trouble.