[Formulajones]

Yep it would be.

I was only suggesting the 68404's if I were setting up the heads, I would have used a shorter stock length valve since the 068 cam was going in.

I assume anyway that's where the extra install height is coming from, which is why I was wondering why an engine builder would do that if the plan was an 068 camshaft.


Unless maybe a bigger camshaft was the plan at some point in the future, or someone changed their mind mid build and the heads were done? Doesn't matter now but curious anyway.

[Jay S]

Might want to consider swapping over to these Howard’s springs and run a .020” shim under them (1.68 installed height). 122 at the seat, Max lift would be .530”. Save the 995s for more cam

https://www.competitionproducts.com/.../#.X4Di3iQ1iaM

[Steve C.]

Looks like Jay has hit the nail on the head, again. Found different springs.

Side note. From one related article in the discussion of reducing the installed height:

To avoid instability, never use more than 0.060-inch–worth of conventional flat shims. Instead, install a spring locator or offset retainers or keys.


.

[Nyairguard]

I can order those no problem with some shims,, can order use my comp retainers and locks or I need to order all the Howard’s stuff?
This is really a restored cruise car 1000 miles per year 5500 redline few burnouts here and there
Thanks for all the help!!

[Nyairguard]

https://www.raceplumbing.net/Howards..._p_168168.html

[Jay S]

It looks to me like the compcams retainers are .020” to big on the diameter for the step for the inner spring. I think the Howard’s spring will hit on that step. You could measure what you have to be sure, but I would just order Howard’s retainers and spring package like the one you found. The keepers will be the same as long and the keeper angle is the same.

[Nyairguard]

Thanks a lot Jay
Seen comp had a 994 spring also on their site
Looks like a direct swap . But probably just order the Howard’s from summit.. quick shipping

[Jay S]

The 994s would work with a .040 or .050 shim. Your better off with less spring rate, even the 350 rate on the Howard’s spring is higher than needed for that cam. You could probably keep looking and find something better yet. It would be nice to find something closer to a 300 spring rate.

Hydraulic lifters can give up quite a bit of cam duration when you add extra spring pressure. Running more pressure than you need is generally counter productive. I would run the Howard’s before the 994s to bring the spring rate down as far as possible.

[Steve C.]

And don't forget that valve springs are going to lose a bit of pressure with run in. Personally I've seen as much as 14 pounds on the seat after a dyno session. And recently I mentioned a build where the valve springs were set up with an initial setting of 130 lbs on the seat, knowing they would lose pressure with run in. The actual pressure after a day on the dyno was 122 pounds.

.

[Jay S]

Here is another Erson spring that would be better yet.. They would need some matching retainers to. I think did this Erson spring on a Crower 60919 in a 455 with 1.5s.

http://www.pbm-erson.com/Catalog/Ers...prings/PBM3000

[Nyairguard]

wow those are cheep, tried looking them up, erson must own the Patten on them they are the only peeps selling those, what retainers should I pick up with those? whats the difference single or dual spring?

man,,, never taught us this in aviation school

[Nyairguard]

this comes up also same part?

https://www.ebay.com/itm/sb-sbc-Chev...4AAOxyn9BRcgkd

[Nyairguard]

https://www.ebay.com/sch/i.html?_fro...+3000&_sacat=0

[Jay S]

Looks the like the same spring in your link. The 1.25 outside diameter is used on a lot of sbc stuff. The only thing you have to watch for on those spring, retainer and keeper kits is the for the keeper angle and a neutral height retainer.. All you need there is a 1.25” retainer with a single groove, common and cheap.

We have turned some engine with single springs and a dampener to 7000. In a big valve Pontiac with a cam and spring package like this can make it to 5500 pretty easily.

Here are some spring descriptions, with pros and cons. Things being equal a dual spring of equal specs is always better. Just not always necessary. A dual spring is probably out there, just takes some work finding it.
https://help.summitracing.com/app/an...-spring-styles

[Nyairguard]

I sent him a question ,, is the diameter a concern mine are larger? any issues with the small diameter , I can order a 1.25 shim assortment just in case

[Nyairguard]

shim kit??

https://www.amazon.com/dp/B000CIUCIA...ing=UTF8&psc=1

[Steve C.]

For interest. A good comprenhensive tech overview of valve springs....

https://www.youtube.com/watch?v=uHw3mWYgO6M


.

[Nyairguard]

this is going to drive me nuts,

https://www.jegs.com/i/Edelbrock/350/5794/10002/-1

[Jay S]

I think you have it figured out. All those will work.

I will throw in one more spring into the mix incase someone runs into your thread later looking for springs and want something in a dual spring. Like I have said, a single spring on this is more than adequate, and I would run one of those you have picked out already.

Isky racing 4205, far right columns in the photo. Dual spring, 320 rate, 125 seat @1.7 . 707-st retainer. Probably not cheap, but also top of the line.

[Nyairguard]

gonna order the Edelbrock 5794,, only ones state made in USA
I thank you for all the help!!