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Discussion Starter · #1 ·
I asked this question in the" Valve train" section, but no response yet.

I am familiar with valve springs used for .800" lift cams in typical 24 degree BBC heads. But not so much at .700" lift. I believe I want a spring that is within .060"-.100" from coil bind at .710" lift, 250-275# at installed height and, 750-800# at open height.

I already have Manely 221424 springs that come in a kit from Brodix and Brodix Dragon Slayer 320 bare heads. Their recommended installed height is 2.000", 250# at installed height and 800# at open height of 1.150". At .710" lift the open height will be .200"+ from coil bind. (Coil bind is 1.070". Open height would be 1.290" or .220" from coil bind at 2.000" installed height.) The heads flow 370 CFM at 700" lift, but only 371 CFM at .800". I have a cam recommendation from Bullet for .731" gross lift and .710" after .020 lash (277*/266*, 110# lobe separation, 108* intake lobe centerline) based on the Brodix flow sheet. Just a 496" bracket race engine to be built over the winter for next season.

I have looked at Pac 1224 1.625" dual spring and Pac 1225 1.550"dual spring, but they are still too far away from coil bind even if I decrease the installed height.

Parts availability not withstanding, what else will work and be a good match for this combo? 3000# big tire door car, 1/8 mile track. PG, 5800 converter, 4.56 gear, 7000 max RPM.
 

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How about the 442 or 441? Yes they are 1.560/1.570 diameter but look like they will get you closer to coil bind.

As a comparison my GM 781 irons use the Manley 424’s. The intake is .805” measured at the valve with the 424 spring. 1.8 Comp rocker 0.832” lift minus 0.020” lash. There is a little deflection there that’s why it is not 0.812” measured. That is a 2.100 install height. Using Trend 7/16” 0.165” wall push rods with guide plates on both intake and exhaust.

Exhaust measures 0.695” at the valve, 1.73 rocker 0.726” lift minus 0.022 lash should be 0.704” again deflection. 1.950 install height.

My point being you will want to check the actual valve lift at the valve with the actual spring you are going to use so that you accurately set up close to Coil Bind with the parts being used.


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Discussion Starter · #4 ·
I checked out those specs on the Isky and Manley springs. Thanks. I had not looked art the catalog page that had the Oval track specs. The 441 springs and the 9995 springs look near identical in specs The 442 springs do not have dampers and are 20 grams lighter. But they are all pricey for just .700" lift. $400-$500. The springs I have are for .850 lift max and 800# at max lift. They are $300 range. Aren't the Tool room spring actually PSI made?
 

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I’m not sure who makes the Tool steel springs. I agree $4-$500 for springs for 0.710” lift and 7000 rpms is really pricy! Wish they would include a price list with the catalogs but given where the economics are right now prices are only going up daily!


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Discussion Starter · #6 ·
K Motion K-1000 was suggested now too from "Valvetrain" section question. Have not run those in a long time.
 

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I run the 443 Manley and .700 lift.
Assemble everything with lash and check the lift with checking springs.
You lose .030 with real springs.
If you want PAC springs I’ll send you a phone number.
 

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I believe I want a spring that is within .060"-.100" from coil bind at .710" lift, 250-275# at installed height and, 750-800# at open height.
I'm not sure if what you want is what you need but if it is, PSI 1571 ML gets you close.

1.97 installed height 297 on the seat
.71 lift, 716lbs
Which puts you at .060 to coil bind.
 

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I checked out those specs on the Isky and Manley springs. Thanks. I had not looked art the catalog page that had the Oval track specs. The 441 springs and the 9995 springs look near identical in specs The 442 springs do not have dampers and are 20 grams lighter. But they are all pricey for just .700" lift. $400-$500. The springs I have are for .850 lift max and 800# at max lift. They are $300 range. Aren't the Tool room spring actually PSI made?
You get what you pay for!
Valve springs aren't a place to save money...
 

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Last time I needed some springs I just called PSI. Guy over there (can't remember his name) has always helped me out and never steered me wrong.
 

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. Aren't the Tool room spring actually PSI made?
The the Isky Tool Room springs are made by PSI. Isky used to have an exclusive deal with PSI, where only they could sell PSI springs with dampers. That deal is what drove Manley to go with Associated spring for their Nextec springs.The deal ended years ago.
As for price, those Isky (PSI) springs will last about 3 times longer then those cheaper springs. There's also a much smaller chance of failure. That makes them a deal.
 

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If you want to save as much money as possible and maintain a decent spring, I would look at the PAC-1243's.
 

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Potentially a comp conical? 7256 maybe? I use that on my 7000 rpm turbo bbc with near mid .700”. Makes it near 135 lb seat lol.
 

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Isky tool room are well worth money spent.They will survive a beating for along while.
 
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