How much can you cut the spring pad down on 70 351w heads?

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NXBOY
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How much can you cut the spring pad down on 70 351w heads?

Post by NXBOY » Tue Jan 16, 2018 3:27 am

Cutting for dual springs and be nice to have another .050 of clearance and use + .050 locks to get a 1.90 installed height hopefully with GT 40 stainless replacement valves. Heads wont have the roof raised just trenched. Just never seen a stock head with recessed seat pads.Thanks.., Ed

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Re: How much can you cut the spring pad down on 70 351w heads?

Post by SupStk » Tue Jan 16, 2018 4:10 am

They aren't too thick. .050 wouldn't be an issue but more, go at your own risk.
Is there a reason you can't use longer valves?
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Re: How much can you cut the spring pad down on 70 351w heads?

Post by ProPower engines » Tue Jan 16, 2018 11:47 pm

I did a couple sets a while back and used a 924 comp spring at 1.900 no problem using a 10 degree retainer which is +.100 installed height anyway after trimming the spring seat and guide for seals.
I did use an ID locator which was .060 thick and cut the heads down in the spring pad area to suit. No issues
I believe you should be able to get 1.900 with 7 degree stuff as well :D
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Re: How much can you cut the spring pad down on 70 351w heads?

Post by NXBOY » Wed Jan 17, 2018 12:09 am

Ordering budget GT 40 valves. They say there 5.70 long with like a .395 stem. I'm using roller tip aligned rockers so thats good, but tips seem taller then factory windsor heads from memory. I will be using comp 10 degree stuff too. He will be cutting for double springs right after I get the guides delivered and he gets them installed. Guess I need to order the valves too.

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Re: How much can you cut the spring pad down on 70 351w heads?

Post by ProPower engines » Wed Jan 17, 2018 12:30 am

The GT 40 head uses a different valve then the old 351 does.
If I were you I would machine the heads and check the valve length needed before ordering valves.
Ferria sells a +50 valve length as well as a +100 long valve which will make the package much more simple to put together.
Because you will need to get push rods anyway why not figure out what valve length you need 1st that way you will save on machine work time.
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Re: How much can you cut the spring pad down on 70 351w heads?

Post by Walter R. Malik » Wed Jan 17, 2018 10:45 am

NXBOY wrote:
Wed Jan 17, 2018 12:09 am
Ordering budget GT 40 valves. They say there 5.70 long with like a .395 stem. I'm using roller tip aligned rockers so thats good, but tips seem taller then factory windsor heads from memory. I will be using comp 10 degree stuff too. He will be cutting for double springs right after I get the guides delivered and he gets them installed. Guess I need to order the valves too.
I think you probably mean 5.07" long and .395" tip length; they are 11/32" stem diameter.
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Re: How much can you cut the spring pad down on 70 351w heads?

Post by NXBOY » Wed Jan 17, 2018 1:25 pm

Yes, 5.07 length. .343 to be exact as ford valves are bigger then most chevy 11/32 and a .395 stem tip! Guess as hard as screen is to see I don't need to be posting late LOL. Thanks, I'll take a valve to him and check height, we added a 30 angle and that probably gained .025 installed height. Boy I love his Serdi Machine ! Anyway I believe 1.85 is all i need and already got 10 degree retainers and + .050 locks. I did notice the short installed height of GT40s but with Two different retainers they use I didn't know if that was part of it. I went over there to visit and maybe flow a head , all in a sudden he was doing a serda Valve job for free lol. Wasn't prepared obviously lol. But he saved me a ton off time in the bowls.I will be using custom length pushrods.Thanks PRO

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