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Old 08-16-2019, 07:50 AM   #25
Bored&Stroked
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Join Date: Jan 2011
Location: Central Ohio
Posts: 2,111
Default Re: FH Valve Springs

Here is some data on spring pressures - that I compiled via my own tests . . . will give you some ideas on options:

Flathead Spring Pressures
Author: Dale Hays, Vintage Horsepower, daleohays@gmail.com
Date: 08/14/2019

The following was done with a hydraulic spring tester – have used it for quite a few years and it is quite accurate (until you get below about 50 PSI).

1. Isky 185G – Single Spring (new)

• 110# @ 1.900
• 100# @ 1.950
• 85# @ 2.00

2. Isky 185G- Single Spring (used)

• 180# @ 1.605
• 82# @ 2.00
• 50# @ 2.125

3. Iaky Dual Valve Springs (I don't use them on anything)

• 80# @ 1.765
• 180# @ 1.390

4. Ford 49-53 – 0BA-6513 (from Mac VanPelt)

• 60# @ 2.00
• 45# @ 2.125

5. Lincoln Zephyr – 86H-6513 (from Mac VanPelt)

• 82# @ 2.00
• 55# @ 2.125

So - if I was going to put say a .375 Potvin 3/8 cam in a street engine, I think I'd use the LZ springs from Mac and I'd install them at 2.0625 . . . should give me about 65 lbs on the seat. So there yah have it . . . . one more opinion to add to the mess! LOL
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