AFR Heads question
Thread Starter
Team Owner
Joined: Mar 2006
Posts: 53,282
Likes: 3
From: God Bless America
AFR Heads question
I was talking to a shop today about installing the new AFR Mongoose heads and maybe changing the push rods. This whole thing started after I read an article in the November 2006 Hot Rodding magazine titled "POWER PLAY". In this article they are able to achieve 573 HP and 504 foot pounds of torque out of the LS2, by installing these heads, a FAST intake, new cam, and long tube headers. Anyway the question came up about what these heads would do to the compression ratio considering the .75 inch thick deck that these heads have. So I was curious if anyone has installed these and did you maintain the same compression ratio or was some milling required? Second, there was some debate on leaving the stock pushrods versus changing to some hardened rods. The article called the stock pushrods weak and replaced them. The shop wasn't so sure and thought it would be better for the rod to give if there was a problem versus something else. I am very interested in the articles approach because the thought going in was to create a reliable durable package that was both street and track friendly. I would appreciate any comments from the forum experts. Thanks
Racer
Joined: Aug 2005
Posts: 425
Likes: 0
From: odessa TX
afr
I have installed many of the afr head packages both 10.5 and 11.5
they both work very well.
I've put well over 50k miles on them
with no problems..
I always install as many upgrades as I would want to do at one time(less down time and the less you have your engine open the less chances you may run into problems)
any questions email udriveslow@yahoo.com
(gm dealer)
they both work very well.
I've put well over 50k miles on them
with no problems..
I always install as many upgrades as I would want to do at one time(less down time and the less you have your engine open the less chances you may run into problems)
any questions email udriveslow@yahoo.com
(gm dealer)
Drifting
Joined: Jul 2003
Posts: 1,796
Likes: 1
From: Annandale VA
There are two schools of thought on hardened pushrods. Pushrod damage is usually caused by over-revving the engine (such as missing a downshift) or by excessive valvespring pressures, or sometimes both. The contrarian view is that it's better to bend a pushrod than to bend a valve, so leave the OEM pushrods in. The mainstream view is what the article cited --- that the OEM pushrods are weak and need to be replaced.
Aside from the reduced risk of failure, hardened pushrods will flex less at higher RPMs, and pushrod flex can affect valve timing and increase valvetrain wear.
If you are running milled heads, or a non-standard deck height, you will probably need shortened pushrods. A standard mill of .030" usually requires a 7.35" pushrod, vs. the OEM length of 7.4".
Aside from the reduced risk of failure, hardened pushrods will flex less at higher RPMs, and pushrod flex can affect valve timing and increase valvetrain wear.
If you are running milled heads, or a non-standard deck height, you will probably need shortened pushrods. A standard mill of .030" usually requires a 7.35" pushrod, vs. the OEM length of 7.4".
Drifting
Joined: May 2005
Posts: 1,254
Likes: 0
From: Ft. Liquordale Florida
I'm running AFR 225's. Got the 72cc milled down to 70cc - to drop compression slightly for more boost.
Go with the hardened pushrods. Also (word to the wise) check the valves & springs BEFORE you install. Had an issue that almost cost me a bottom end. PM me if you want more details (I'm not quite ready to slam them publicly - YET).
Alot of valvetrain upgrades are greatly dependant on whether you're going to a more aggressive cam profile. If you're staying stock, you can likely leave everything else stock.
After my "meltdown", I'm putting in crane high performance lifters, Gold Race roller rockers, and a hi-volume oil pump as "extra insurance" against future valvetrain problems.
Personally - sometimes I wake up in the morning (lately), and just wanna throw all the stock parts back on, take it to the stealership and trade it in on a nice SUBURBAN. Then again, I haven't come up against anything on 4 wheels that can touch my car on the street...
Rick
Go with the hardened pushrods. Also (word to the wise) check the valves & springs BEFORE you install. Had an issue that almost cost me a bottom end. PM me if you want more details (I'm not quite ready to slam them publicly - YET).
Alot of valvetrain upgrades are greatly dependant on whether you're going to a more aggressive cam profile. If you're staying stock, you can likely leave everything else stock.
After my "meltdown", I'm putting in crane high performance lifters, Gold Race roller rockers, and a hi-volume oil pump as "extra insurance" against future valvetrain problems.
Personally - sometimes I wake up in the morning (lately), and just wanna throw all the stock parts back on, take it to the stealership and trade it in on a nice SUBURBAN. Then again, I haven't come up against anything on 4 wheels that can touch my car on the street...
Rick
