How much lift can stock GT40P springs handle? Getting Cam, need to know!

astronut1885

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Jan 31, 2002

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Assonet, MA

Jan 18, 2004

#1

• Jan 18, 2004

• #1

Hey guys. I am going to get a new camshaft for my engine buildup, and I want to know if the springs on my new heads can handle it. I have a set of GT40P heads on their way to me. They have had enlarged (1.54") exhaust valves put in, and are brand new. I have no idea what springs are on them, but if they should be stock, how much lift can they handle? I am going to be using a Trick Flow stage 1 cam, with specs:
Specifications:
* Advertised duration: 275 intake/279 exhaust
* Duration at .050 in. lift: 221 intake/225 exhaust
* Gross valve lift: .499 in. intake/.510 in. exhaust
* Lobe separation: 112 degrees
* RPM range: 2,000 to 5,500
Any help is greatly appreciated.
Thanks!

 

astronut1885

Founding Member

Jan 31, 2002

1,899

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Assonet, MA

Jan 18, 2004

#2

• Jan 18, 2004

• #2

ttt

 

B

bapford

New Member

Jan 17, 2004

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Jan 18, 2004

#3

• Jan 18, 2004

• #3

spring works

astronut1885 said:

ttt

Click to expand...

I don't know if this helps, but those springs should be just fine for that advertised lift if you use the 1.6 rockers. Some even run the 1.7's, but it is definately close depending on the pistons. Whatever, check this before you get too far. I ran FMS 1.72 rockers on the GT40 heads from an early Lightning with no problem, and this was stock pistons at first, then some TRW forged later.

 

mike keirstead

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Aug 6, 2003

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ROLLING A JOINT

Jan 19, 2004

#4

• Jan 19, 2004

• #4

astronut1885 said:

Hey guys. I am going to get a new camshaft for my engine buildup, and I want to know if the springs on my new heads can handle it. I have a set of GT40P heads on their way to me. They have had enlarged (1.54") exhaust valves put in, and are brand new. I have no idea what springs are on them, but if they should be stock, how much lift can they handle? I am going to be using a Trick Flow stage 1 cam, with specs:
Specifications:
* Advertised duration: 275 intake/279 exhaust
* Duration at .050 in. lift: 221 intake/225 exhaust
* Gross valve lift: .499 in. intake/.510 in. exhaust
* Lobe separation: 112 degrees
* RPM range: 2,000 to 5,500
Any help is greatly appreciated.
Thanks!

Click to expand...

They don't handle alot of lift. The gt-40 COBRA springs are the good ones. I have a set of cobra springs. They are good to .550 lift. They are in great shape. Just had them all checked and they all are in spec. I will sell them if you are interested.I have the locks and retainers also. Let me know.

You could use the stock springs but why put all that money into a motor and WAIT for it to let go. They are not that good of a spring. Just get a good set and be done with it.

Let me know if you want them.

Mike

 

astronut1885

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Jan 31, 2002

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Jan 19, 2004

#5

• Jan 19, 2004

• #5

How much are you looking to get? My budget is stretched very thin right now, but if you can cut me a deal, I may be interested. I still have to see what is on the heads when they arrive. Thanks.

 

mike keirstead

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Aug 6, 2003

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Jan 19, 2004

#6

• Jan 19, 2004

• #6

pm sent

 

astronut1885

Founding Member

Jan 31, 2002

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Assonet, MA

Jan 19, 2004

#7

• Jan 19, 2004

• #7

and returned

 

astronut1885

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Jan 31, 2002

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Assonet, MA

Jan 20, 2004

#8

• Jan 20, 2004

• #8

I got the heads in today, and I don't think that the springs are stock. They have a coil inside the regular coil. Pics can be seen in the link in my sig, go to the last page. If anyone has any ideas what they are, let me know.
Thanks.

 

SwAmPf0x

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Dec 29, 2001

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Hell Hole Swamp

Jan 20, 2004

#9

• Jan 20, 2004

• #9

Im running .510 on the stock springs, gonna upgrade soon but I havent had any problems

 

astronut1885

Founding Member

Jan 31, 2002

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Assonet, MA

Jan 20, 2004

#10

• Jan 20, 2004

• #10

BTW, change in camshaft. I am now going with the E303 FRPP cam. Please no flaming of my cam choice. Just info. on the springs. Thanks.

 

1995COBRA

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Alamo, Tx.

Jan 20, 2004

#11

• Jan 20, 2004

• #11

I am using the Ford SVO springs & retainers, and they work just great. I had them on my old E7's, then transfered them to my GT40P's. I was also running an "E" cam. Just take the springs to a machine shop, and have them pressure test them, to see if they can handled atleast a .500" lift.

Leo