Higher lift vs decking heads
Thread Starter
Teching In
Joined: Oct 2006
Posts: 7
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Higher lift vs decking heads So here's the deal. I can't afford a good set of heads right now so I'm planning a cam /spring/pushrod/lifter/oilpump/timing set change on my ls1. I do not want to flycut. I dont want to kill the gas mileage ,drivability and low end so i'm planning a cam in the 224 to 230 duration range .
So here's my question . Which would give me more power. A lower lift cam and decking the stock heads or a higher lift cam. Should I get a max lift cam (eg new lsr 227/235 .614/.621 ) or an xer 580ish lift cam and deck the heads .030-.040 to bump the compression.
Any opinions appreciated.
Here's a short video of the locost the motor is currently installed in firing up.
http://www.youtube.com/watch?v=Sw3cShWejS8
So here's my question . Which would give me more power. A lower lift cam and decking the stock heads or a higher lift cam. Should I get a max lift cam (eg new lsr 227/235 .614/.621 ) or an xer 580ish lift cam and deck the heads .030-.040 to bump the compression.
Any opinions appreciated.
Here's a short video of the locost the motor is currently installed in firing up.
http://www.youtube.com/watch?v=Sw3cShWejS8
It's not the lift that affects the piston to valve clearance, it's the duration. The piston is not at top dead center when the valves are at max lift. The valves will be just starting to open or almost closed when the piston is closest, and how close is determined by the duration and lobe separation. Personally I wouldn't go thru the trouble or expense(new head bolts and gaskets) of pulling the heads just to mill them if you are gonna run a cam in the 224-230 range.
Thread Starter
Teching In
Joined: Oct 2006
Posts: 7
Likes: 0
here is the fixed link.Thanks for the opinions. I understand that with a cam like "El Torro" PTV starts to get tight and I dont think you could mill the heads with that cam. So I guess what I am asking is Instead of running a huge lift lobe and having the coresponding increase in Valve train costs by having to run the best valvesprings wouldn't it be easier to run a slightly smaller lift , less expensive springs and just bump the compression a bit .
http://www.youtube.com/watch?v=9eyTfN0StCs
phil
http://www.youtube.com/watch?v=9eyTfN0StCs
phil
Last edited by philmrx8; Mar 2, 2009 at 07:01 PM.
