Push rod and cam lift ?

danny waters sr · 02-24-2011, 10:49 AM

On my stocker engine( 66 ,283 ) i am checking 375-377 lift and allowed 399. I checked with a 225 long push rod and lift went up to 394-395. Is there much hp gain or et gain with this change ?. Also i do not have the trick lifters in this motor.. Just wondering if i need to buy a set of push rods or not.....More interested in et gain if any .You can pm me if you do not want to answer on here/..Thanks in advance for your replies...

Alan Roehrich · 02-24-2011, 12:00 PM

Danny,
If you just go longer, you may not see a gain. But if you upgrade in stiffness, you probably will. For example, if you're using an 0.060" or 0.080" wall 5/16", and you upgrade to a 0.125" wall 3/8", you may see HP.

A lot of us give up 0.010 or so lift, just to be legal without question, and to prevent having to buy individual pushrods. For example, I may run 0.505" or 0.510" lift instead of 0.518", to stay legal under the 0.520" limit for my engine, and because I'd have to buy a lot of pushrods individually instead of buying a set, to get each valve to 0.515" to 0.518".

danny waters sr · 02-24-2011, 09:39 PM

Thanks Alan, just thinking if it is worth the trouble ,time and $$$'s...Tested this past weekend with freshed up motor with a few tweaks and picked up a little over a tenth in the 1/8 th mile with the tall 1/4 mile tires on it. Really trying to get another tenth or two without a lot more $$$'s to spend......I'm getting there as $$$'s will allow. Not complaining as i am very pleased so far with the results.....

Grant Eldridge · 02-24-2011, 10:17 PM

You might want to check the contact pattern between the valve stem tip and the rocker arm using the longer pushrod before deciding to order pushrods. If they move the contact patch too far off center, you might need to obtain some of the lift by having a cam ground with extra lobe lift to obtain close to the spec lift.
On my BB Chev engine, a .100" long pushrod gave me close to .010" more lift and worked out ok but I am losing .015" in deflection and had to also grind extra into the camshaft. I also think the .125" wall pushrod helps, there's another recent thread on here about a similar issue, hope this helps...

Ed Carpenter · 02-25-2011, 10:02 AM

Quote:

Originally Posted by danny waters sr

On my stocker engine( 66 ,283 ) i am checking 375-377 lift and allowed 399. I checked with a 225 long push rod and lift went up to 394-395. Is there much hp gain or et gain with this change ?. Also i do not have the trick lifters in this motor.. Just wondering if i need to buy a set of push rods or not.....More interested in et gain if any .You can pm me if you do not want to answer on here/..Thanks in advance for your replies...

Danny PM me the length your looking at. I have some. Ed

02-24-2011, 10:49 AM	#1
danny waters sr VIP Member Join Date: Apr 2007 Location: lagrange,nc Posts: 2,224 Likes: 1 Liked 0 Times in 0 Posts	Push rod and cam lift ? On my stocker engine( 66 ,283 ) i am checking 375-377 lift and allowed 399. I checked with a 225 long push rod and lift went up to 394-395. Is there much hp gain or et gain with this change ?. Also i do not have the trick lifters in this motor.. Just wondering if i need to buy a set of push rods or not.....More interested in et gain if any .You can pm me if you do not want to answer on here/..Thanks in advance for your replies... __________________ Danny Waters, Sr / 73 Duster "340"

02-24-2011, 12:00 PM	#2
Alan Roehrich Veteran Member Join Date: May 2006 Location: Murfreesboro TN Posts: 5,107 Likes: 1,564 Liked 1,796 Times in 409 Posts	Re: Push rod and cam lift ? Danny, If you just go longer, you may not see a gain. But if you upgrade in stiffness, you probably will. For example, if you're using an 0.060" or 0.080" wall 5/16", and you upgrade to a 0.125" wall 3/8", you may see HP. A lot of us give up 0.010 or so lift, just to be legal without question, and to prevent having to buy individual pushrods. For example, I may run 0.505" or 0.510" lift instead of 0.518", to stay legal under the 0.520" limit for my engine, and because I'd have to buy a lot of pushrods individually instead of buying a set, to get each valve to 0.515" to 0.518". __________________ Alan Roehrich 212A G/S

02-24-2011, 09:39 PM	#3
danny waters sr VIP Member Join Date: Apr 2007 Location: lagrange,nc Posts: 2,224 Likes: 1 Liked 0 Times in 0 Posts	Re: Push rod and cam lift ? Thanks Alan, just thinking if it is worth the trouble ,time and $$$'s...Tested this past weekend with freshed up motor with a few tweaks and picked up a little over a tenth in the 1/8 th mile with the tall 1/4 mile tires on it. Really trying to get another tenth or two without a lot more $$$'s to spend......I'm getting there as $$$'s will allow. Not complaining as i am very pleased so far with the results..... __________________ Danny Waters, Sr / 73 Duster "340"

02-24-2011, 10:17 PM	#4
Grant Eldridge Member Join Date: Jul 2007 Posts: 124 Likes: 0 Liked 0 Times in 0 Posts	Re: Push rod and cam lift ? You might want to check the contact pattern between the valve stem tip and the rocker arm using the longer pushrod before deciding to order pushrods. If they move the contact patch too far off center, you might need to obtain some of the lift by having a cam ground with extra lobe lift to obtain close to the spec lift. On my BB Chev engine, a .100" long pushrod gave me close to .010" more lift and worked out ok but I am losing .015" in deflection and had to also grind extra into the camshaft. I also think the .125" wall pushrod helps, there's another recent thread on here about a similar issue, hope this helps...