valve springs for roller cam

i am going to be running this cam with a429 cobra jet aluminum heads,what springs should i be using for it?
The M-6250-A514 cam and tappet kit features an induction hardened steel mechanical roller cam with the following specs:
Feature
Max lift
Duration @ .050" lift Centerline
Lobe separation Events @ .050" open
close
Intake .647" 254° 107°
20° BTC 54°ABC .020" .014"
112°
Exhaust .647" 258° 117°
66° BBC 12°ATC .020" .014"

what installed height do you have to work with?

they check 1.970 .i was told the heads came from you,from a 545 in colorado.

hbstang wrote:they check .970 .i was told the heads came from you,from a 545 in colorado.

You must mean 1.970, look at 947-16 comp cams

Hi-Tech Triple Valve Springs
O.D.: 1.645"
I.D.: .635"
Seat Load: 338 lbs/in @ 2.000
Open Load: 849 lbs/in @1.250
Coil Bind: 1.145"
Rate: 681 lbs/in.
16/pkg.



save you the trouble of looking

I have used these a LOT

No where in there does it explain anything about the aggressiveness of those lobes and therefore to much spring is better than not enough but, asking the camshaft manufacturer what pressures are needed would be best.

After knowing what pressures are necessary ... then you can find a spring which fits into your package.

what springs did ford use in the 521M-6007-521FT crate engine with this cam?this will never see 6500 rpm.crate engine peaked at 5750 and that was with the scj heads.is there a part number for the springs?

this is the specs on the scj heads as they come from ford.
Assembled with solid roller springs: Closed seat pressure 240# @ 1.900"; Open seat pressure 625# @ 1.200"; Max lift .650"
comp cams has a spring p/n 954 that may work.

PAC 1243.........same unit that's on the current SCJB package. Very good spring.

rmcomprandy wrote:No where in there does it explain anything about the aggressiveness of those lobes and therefore to much spring is better than not enough but, asking the camshaft manufacturer what pressures are needed would be best.




After knowing what pressures are necessary ... then you can find a spring which fits into your package.

right

I would hope his head guy would know how to set these up, these will be around 290/300 and 700 open with that lift +LASH , they will loose about 30lbs
after run in


6500 OR 5000 RPM DOESNT MATTER bounce iS bounce, this is the very reason i see so many broken lifters on these boards, too light of presser, and these spring will last  quite a while with this cam

https://www.summitracing.com/parts/cca-953-16

WoW Comp Cams only wants a 953 spring on a XR292 solid roller which is bigger then the SVO cam. I agree with with others that's too light and am not suggesting them., besides the installed height is wrong for the OP. The old book shows them at 475 at 1.280". Something in the 600lb range would seem better to me.

http://www.competitionproducts.com/PAC-Roller-Valve-Springs-1550-OD-240-1900-625-1200/productinfo/PAC-1243/

Here's the spec.s on the PAC 1243's. Too Light you Bounce Too Heavy you Stress Other Stuff, no winning it seems, sometimes.

dfree383 wrote:

supervel45 wrote:https://www.summitracing.com/parts/cca-953-16

WoW Comp Cams only wants a 953 spring on a XR292 solid roller which is bigger then the SVO cam. I agree with with others that's too light and am not suggesting them., besides the installed height is wrong for the OP. The old book shows them at 475 at 1.280". Something in the 600lb range would seem better to me.

For what it's worth ive  used the 954-16 on XR 292 cams in the past and they worked fine and didn't break anything but floated at 6800-6900, flame suit on.....

I think Comp's pushing that 953 for the stock lenght valves? The 954 seems like a step in the right direction.

dfree383 wrote:The PAC springs would be a good choice imo, the triple ones are way overkill for the mild crane grind that was  used in the crate engines, plus that cam isn't going to make any power over 7000 anyway.

I agree. If it was an all out race engine and going into a high winding 429, sure more spring pressure, a 545 street deal not so much.

dfree383 wrote:

supervel45 wrote:https://www.summitracing.com/parts/cca-953-16

WoW Comp Cams only wants a 953 spring on a XR292 solid roller which is bigger then the SVO cam. I agree with with others that's too light and am not suggesting them., besides the installed height is wrong for the OP. The old book shows them at 475 at 1.280". Something in the 600lb range would seem better to me.

For what it's worth ive  used the 954-16 on XR 292 cams in the past and they worked fine and didn't break anything but floated at 6800-6900, flame suit on.....

floating is bouncing

Comp Cams has their version of the PAC 1243 spring - #943.

EDIT: I looked it up in the archives today ... The required minimum spring pressures for 7,000 rpm using A429 valve train weight with a crate motor cam, (from Crane, who designed it), is 225 on the seat 535 open; (at 640" valve lift).
That's 484 lb/in rate

The PAC-1243 are a circle track spring and are more durable a typical drag race spring.

If a guy wanted to get right down to it......the valves bounce and the springs float.