Valve Spring Choice for Solid Roller Street/Strip

[n2omike]

The 363 SBF is finally getting built. I've gathered most of the parts in 2011, and was waiting for the current engine to wear out... and a rod bolt let go, so here we are! lol

Anyway, the heads are Trick Flow 225 High Ports. They have 2.08 valves with a 2.00" installed height. They came with Isky 9385 springs that have a 245 lb on the seat with a 500 lb/in rate. Good for around 0.720" lift. 0.550" diameter.

These are the cam specs.
Current cam specs are:
(solid roller)
279/291 @ 0.020"
249/258 @ 0.050"
172/177 @ 0.200"
0.4120"/0.4315" lobe lift
0.700"/0.690" lift with 1.7/1.6 rockers
110º Lobe Separation
0.018"/0.022" lash

The car will see plenty of street duty, so I was thinking about going to a more 'modern' set of springs that are lighter and can be used with less pressure for longevity of the valvetrain. Lifters are 0.875" Isky Red Zone with the solid bushings... yes, some were undersized, and sent back and traded.

Below is a little more info on the engine.
4.125" bore Dart Sportsman block, zero decked.
Scat 3.40" crank, internally balanced.
Olivier Rods
Mahle flat tops. 11:1
950HP Holley
Ported Super Victor
TEA 225 High Ports
1-3/4" Tubular Automotive Race Headers.
Crower Stainless Shaft Rockers
3/8" pushrods
ATI dampner
Toploader 4-speed

Car is pump gas (off the bottle) and does go to the track, where it has run a best of 6.26 @ 109 in the 1/8, and 9.87 @ 135 in the 1/4 using a 200 hp nitrous plate... with the solid flat tappet 306 that just let go of a rod bolt. 50 year old Boss 302 crank and rods... but what fails is a 3/8" ARP Waveloc rod bolt!

Anyway, input on valve springs would be appreciated. If I can safely dial down the pressure with some more modern tech, and still spin around 7500 rpm, I'm all ears!

Thanks!

[F-BIRD'88]

Its not going to happen. Thats not a street roller cam.

Set the lash .006" to .010" tighter than cam card and enjoy.
Lifters will need regular inspection and service reguardless.

[n2omike]

It's no daily driver... mostly a weekend toy that comes out in nice weather to be blasted around... and go to the track 2-3 times per year.

You hear all this talk about lightweight, modern valve springs that get by with less pressure do their reduction in mass. My question, what would be a good modern replacement for an 'old school' 1.56" diameter 0.700" valve spring?

[F-BIRD'88]

In order to run a lighter spring (force) the cam action (net valve dynamic motion) needs to be tamed down AND the whole valve train moving mass needs to be lighter mass.
The high rocker ratio accelerates -multiplies the forces involved.
It does not matter how often you intend to drive it.

With nitrous especially you do not want to short this combo on valve motion control.

[BirdMan]

To be able to use lighter springs you need lighter valve train components like lighter wt valves like .312/.315 titanium or at least SS this size, ti retainers and valve locks. It looks like that cam is very quick movement.

For my 347 I have .343 Ti valves hard coated, 1.7 T&D shaft rockers, valve lift .650 238/245 @ .050 and longer duration which I hope will be easy on valvetrain.

[CamKing]

The problem is, most of the smaller lightweight springs that are made by PSI and PAC, are designed for more lift then you're running. so you would either be too far from coil bind, or you would have to install them tighter, whitch would give you as much pressure as you have now.

What I recommend for your cam, and RPM rang, is the ISKY 9915, installed at 1.950"

[n2omike]

The problem is, most of the smaller lightweight springs that are made by PSI and PAC, are designed for more lift then you're running. so you would either be too far from coil bind, or you would have to install them tighter, whitch would give you as much pressure as you have now.

What I recommend for your cam, and RPM rang, is the ISKY 9915, installed at 1.950"

Thanks for the response, Mike!
So, you think the Isky 9915, which installs at around 195 lbs will be enough... and the 9385 at 245 lbs isn't needed? They both have the same 500 lb/in rate. The 9385 is just what the heads came with, and is not part of a cam recommendation... just a generic 0.720" max roller spring.
Thanks!

[bob460]

What about psi CT 1526 ML Dual... 1.460" 195 lbs @ 2.000" 530 lbs @ 1.250" 0.750" 1.150"

Or the comp cams dual conical valve springs 7245.......

Dual Conical Valve Springs
Rate: 600 lbs
Inner Diameter: .646'' Top, .861'' Bottom
Outer Diameter: 1.442'' Top, 1.657'' Bottom
Seat Load: 150 lbs at 2.000''
Open Load: 630 lbs at 1.200''
Coil Bind Height: 1.115''

[Turbobuick6]

If you are looking for a small diameter spring to run street/strip with, I would recommend the PAC-1530 (1.284" OD) setup @ 1.950".

185 seat and 575 open @ .060" from bind.

[mag2555]

That size port and Intake valve with that cid is going to be making peak hp above 7500 my friend!

[stealth]

That size port and Intake valve with that cid is going to be making peak hp above 7500 my friend!

Might be a good time to upgrade the pushrod diameter from 3/8 too..

[n2omike]

That size port and Intake valve with that cid is going to be making peak hp above 7500 my friend!

Might be a good time to upgrade the pushrod diameter from 3/8 too..

This being a 302 style block, the pushrods are only about 6.8 to 7.0 inches long. You guys think there is something to be gained by going to something bigger than a high quality 3/8 unit? I did call Bullet, and he liked the current Isky 9385 springs at their installed 245 lb seat pressure and 500 lb/in rate. Said the Isky was a good 'endurance' spring, and should last a while.

The above cam was purchased, partly because I was able to get it with the 'ever wear' gear that I can use a melonized distributor gear with. One of these days, I'm going to order one of your cams, Mike Jones!

As for shift point... If I were going all out, I would have a cam around 256/266 and more lift.... along with a solid 8k shift point. Trying to get a little more service life out of it. Can't afford to build these on a regular basis. lol

Thanks!

[turbo camino]

Hang on, I thought the melonized distributor gear worked with any steel billet cam, whether OE or aftermarket? And if the cam had a pressed iron gear you could use the plain non-melonized distributor gear on it?

[bob460]

If you are looking for a small diameter spring to run street/strip with, I would recommend the PAC-1530 (1.284" OD) setup @ 1.950".

185 seat and 575 open @ .060" from bind.

I emailed PAC about this spring, but they have stopped making them. Looked like a nice street/strip valve spring for the .700 lift range.

[cab0154]

That size port and Intake valve with that cid is going to be making peak hp above 7500 my friend!

the minimum port cross section on that head is only 2.35 sq". if a small cam were in that 363, my calculation gave me 5600 rpm for target peak air speed. so with that cam he is going to use i wouldnt think it would peak would any later than 7200....

This being a 302 style block, the pushrods are only about 6.8 to 7.0 inches long. You guys think there is something to be gained by going to something bigger than a high quality 3/8 unit? I did call Bullet, and he liked the current Isky 9385 springs at their installed 245 lb seat pressure and 500 lb/in rate. Said the Isky was a good 'endurance' spring, and should last a while.

The above cam was purchased, partly because I was able to get it with the 'ever wear' gear that I can use a melonized distributor gear with. One of these days, I'm going to order one of your cams, Mike Jones!

As for shift point... If I were going all out, I would have a cam around 256/266 and more lift.... along with a solid 8k shift point. Trying to get a little more service life out of it. Can't afford to build these on a regular basis. lol

Thanks!

what is the wall thickness on those pushrods? I know straightwall .080" 7/16s were going to rub on my profilers, and I already had the engine assembled, so i ran some .135" wall 3/8" stuff and was told they would be overkill. and thats with an 8.15" pushrod, 590lbs open, 220 on the seat. .670" lift. and i have a 9.2 deck, so taking an inch of length off those pushrods should stiffen them up as well.