Camahafts

November 01, 2024, 12:33 PM

coop5140

Camahafts

How much is to gain from a cam that has a .650 lift to a cam that has a .690 lift? Sbc 434 18 degree heads thanks

November 01, 2024, 05:02 PM

B KING

Do you have flow numbers for your heads?

2BKING
Relaxing

November 01, 2024, 05:39 PM

Goob

This is the most comprehensive data base of cylinder head flow numbers I've found.

http://users.erols.com/srweiss/

If there is a significant gain between those lift openings, you may benefit.

Lots of other numbers to be considered along with gross lift.

Tightening the valve lash or swapping rocker ratio are cheap ways to test the theory.

November 02, 2024, 01:37 PM

coop5140

I don’t have flow numbers, thanks for info though I wasn’t sure if 40 thou is significant, but was thinking its gotta help, thanks guys

November 02, 2024, 02:19 PM

Alaskaracer

Unless you have really bad valve shrouding, I think you'll make more gains from change in lobe duration, intensity, separation, and centerlines than in just lift....

When people change rocker ratios, they forget that it also changes duration slightly...So any gains are likely from a combo of both rather than just one factor...

Mark Goulette
Owner/Driver of the Livin' The Dream Racing dragster
www.livinthedreamracing.com
"Speed kills but it's better than going slow!"
Authorized Amsoil Retailer

November 03, 2024, 09:12 AM

wideopen231

Agree correct duartion and valve open and closing points more important than total lift.

IMO excessive lift is just good for killing springs quicker. Like compression there is a point of little to no gain.

Best thing about a roller setup. You can changes cams all day and only need to buy cams.

November 03, 2024, 10:31 PM

rusty

although i cant say how much .with though heads i think you will see a decent improvement

November 04, 2024, 05:35 AM

Curly1

Depends on a lot of things. If you have the Brodix 18 X heads they do not flow as much as some of better 23* heads. The Brodix 18*C heads are much better.

In any case .650 lift is not much to feed 434 Cubic inches so increased lift (and duration) should help it. The better the heads flow the bigger that difference should be.

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November 04, 2024, 09:03 AM

Goob

quote:
Originally posted by coop5140:
I don’t have flow numbers, thanks for info though I wasn’t sure if 40 thou is significant, but was thinking its gotta help, thanks guys

Did you miss this?

January 23, 2025, 03:23 PM

Stan Weiss

quote:
Originally posted by Goob:
This is the most comprehensive data base of cylinder head flow numbers I've found.

http://users.erols.com/srweiss/

If there is a significant gain between those lift openings, you may benefit.

Lots of other numbers to be considered along with gross lift.

Tightening the valve lash or swapping rocker ratio are cheap ways to test the theory.

Dave,
That web page has not been updated since early 2018.

http://www.magneticlynx.com/carfor/carfor.htm

Stan

January 25, 2025, 09:45 AM

Goob

quote:
Originally posted by Stan Weiss:
quote:
Originally posted by Goob:
This is the most comprehensive data base of cylinder head flow numbers I've found.

http://users.erols.com/srweiss/

If there is a significant gain between those lift openings, you may benefit.

Lots of other numbers to be considered along with gross lift.

Tightening the valve lash or swapping rocker ratio are cheap ways to test the theory.

Dave,
That web page has not been updated since early 2018.

http://www.magneticlynx.com/carfor/carfor.htm

Stan

Thanks for the update!

That old page still works for me though, as all of my stuff is mid '80's to mid '90's technology.