cam lift

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Mar 21, 2005 | 03:17 PM

brennamp

Thread Starter

New User

Joined: Mar 2003

Posts: 11

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From: Pullman, WA

cam lift

I have a 79 460, stock, I was wondering how much lift the stock valve springs will hold?

Mike

Mar 22, 2005 | 10:18 AM

wizzard351

Postmaster

Joined: Sep 2004

Posts: 3,166

Likes: 2

From: wi

its always a good idea to change springs when doin a cam swap cuzz the ol'stockers will lose preshure with age but if ya stay under a .500 lift ya shuold be ok you also change the springs with out takin of the heads if ya have acses to an air compreser just take out the plugs and run the air line into the head and change the springs

Mar 23, 2005 | 08:12 PM

The "Mad Porter"

Mountain Pass

Joined: Aug 2004

Posts: 143

Likes: 3

From: Tacoma, WA.

The problem is not the springs even though they are garbage...

Quote:

Originally Posted by brennamp

I have a 79 460, stock, I was wondering how much lift the stock valve springs will hold?

Mike

The issue lies with retainer to seal/guide clearance. Once you get to about .530" lift you can run into retainer seal contact.

That being said the stock springs are barely adequat for a stock cam. Replace the springs with matching units from the cam manufacturer. The extended RPM range of a different cam will require better springs for good valve train control.

As a side note you can change springs with nothing more than the cylinder you are working on at TDC. The valves will not drop down into the cylinder. You can easily change springs and seals to accomodate more lift.

Regards,
SMJ/RHP
http://reincarnation-automotive.com
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