Milling Heads and Changing the Angle.

[fifesjeep]

This is for those who have experience or theories on milling the stock AMC heads for performance gains. I'm having the heads evenly milled .035" :wink:
My questions are:
-If the heads were to be angled slightly and then milled, What type of results can I expect with performance... Loss/Gain... Pro's/Con's... Flow Characteristics etc.?

I know that a flow bench and a dyno would be the two vital keys to varify any true/real results. But, as I looked at the heads, I wondered if there is a better angle for the atomized fuel/air mixture to flow into, combust and flow out the chambers...

-How dramatically will this change the flow characteristics and quenching period?

-Is there one angle better than the other?

-Is there a motor out there with near specs as an AMC V-8 that we could use as a base example (Bore/stroke/angle of combustion chambers etc)...

I know that there will be extra modifications included if the head angle is changed.

-Does anybody have any thoughts on this...

-MC, Do you have the specs or the approximate angle of the combustion chamber? I guess if I was good at Geometric Construction/physics etc I could probably figure something out... lol. (Time to hit the books). I have some clay, I guess I could stuff some into the chamber in order to get a rough check on them... I'm not sure that I have enough clay though. :-|

-If you start selling Used Parts will you offer stock heads that have been milled to various compression ratios etc?

I think the poor mans compression bump would be a great seller for the low budget builders... :t:
I have 3 sets of 502's laying around... lol. Do I hear ginnie pig or was that a sacrificial lamb.

My buddy pointed me to AEROHEAD Racing and they're selling the 502's with the larger valves 2.08/1.74? I emailed them and asked them a few questions about their practices/set-ups just to ensure that they're not just tossing the valve in without deshrouding properly etc and I haven't recieved a reply yet... :idea: Has anybody ever delt with these guys? They're asking $600/$700 for these used/reconditioned heads etc. Don't get me wrong there has been a lot of work done to the heads but I was looking for clarifiaction and never got it so I am wondering if anybody has purchased a set of heads from them...

Rich

[jeepsr4ever]

So basically now you have added 1 point to your compression ratio. I dont have the angle in front of me but once you change it you run the risk of bottoming out pushrods through the head, hitting the valves with your pistons and possibly hitting the cylinder wall.

[fifesjeep]

So basically now you have added 1 point to your compression ratio.
Yeah man... I'm looking for a little more squeeze...


I dont have the angle in front of me but once you change it you run the risk of bottoming out pushrods through the head, hitting the valves with your pistons and possibly hitting the cylinder wall.
Yeah, I'm not talking about a dramatic change in the angle or anything... 1 degree to 3 degrees. I have yet to trig the angles in order to determine how much it would push the valves towards the piston... I figured worst case scenario you would have to re-cut the eyesbrows (Probably not efficient for performance) or better yet have a flat-top piston cut with the eyebrows in reference to the valve angle.
PushRods... Might have to be changed? Depending on length... Hmmm, what about the valve geometry? I imagine the pushrod would ride more on the backside of the roller Rocker cup... I guess a Slightly longer roller rocker might be needed?
As for the valves hitting the Cyllinder walls? Possibly but, I don't imagine that the change would be so great the it would swing the valves that much closer to the cylinder wall. But then again, I haven't done the math yet.
So what about Selling Remaned AMC Heads that have been modified for the budget builder? :? :razz: :!: :t:

[tufcj]

If there was any real benefit, don't you think AMC would have done it? Thousands, if not 10s of thousands of R&D before these engines were produced.

Bob
tufcj

[jeepsr4ever]

If there was any real benefit, don't you think AMC would have done it? Thousands, if not 10s of thousands of R&D before these engines were produced.

Bob
tufcj

You mean like canting the valves :wink:

[fifesjeep]

If there was any real benefit, don't you think AMC would have done it? Thousands, if not 10s of thousands of R&D before these engines were produced.
Here's my simple answer your question... No...
Here's my reasoning behind that...
If anything AMC spent most of their R&D in flowing their heads and re-designing the ports/chamber sizes etc. AMC had to of known that their heads were the cap on the bottle so to speak. If the heads can't flow it the heads won't give it... I also don't think AMC had the luxury to completely re-design their heads to get the maximum performance out of them. I'm sure that if AMC had a sound financial backing and a large following of all walks of life that they would've produced something mind blowing years down the line But, that just wasn't the case.
As is, by the time AMC started producing the known AMC V-8's with the better flowing dog-leg heads they were already behind the power curve for performance. (Arguementively speaking). The other "major" manufacturers were making large strides in their performance catagory and getting the crowds to follow. As AMC was falling further behind they were trying to figure out ways to draw more money and get the attention of the people FAST. If a society is hungry for performance, you feed it performance. If a society want's a cheap & reliable vehicle, you give it a cheap & reliable vehicle. If they want a mixture of both you make sacrifices and AMC did that... Did it hurt them in the long run... who knows for sure. AMC did alright for a little while but there were too many factors/obstacles that played against them. What would you consider to be the Peak years for AMC power?... 68 to 71-ish... And what were the other manufacturers glory years?... Compare the body styles as well as the various options. The typical human behavior/responses are like a cult of personality, one man does it and stands high... so everybody else want's to do it... So, they follow the leader so to speak. AMC vehicles were cheaply priced and ideal of the average blue shirt worker but dang... What were they thinking when it came to their body styles? If they had such great and inovative "thinkers" why didn't they create better body styles?. #-o I could be way off basis and it wouldn't be the first time but, researching AMC history, reading about their various problems and match that against a rapidly changing economy they were doomed from the get go. It was only a matter of time before they were pushed into the funnel head first leaving trails of what could've been.
This is a blanket statement/question; What other manufacturers offer various degress of heads? and Why is this? Flow characteristics? Performance? AMC was definitely onto something great but I don't think they had the full kitchen to play with during those years of a performance hungry culture/society.

[GASGAS250]

AMC cylinder heads are 18 degree, sbc heads are 23 degree, olds heads are 11 degree, and i dont know about the rest, but i do know that alot of aftermarket sbc heads are changed to 18 degree, from the stock 23 degree for better flow, and some really trick sbc heads are 14 degree, but i dont see any better flow from the 14's than the 18's.
As far as a siemezed cylinder head with symetrical ports i dont see any better than the 18 degree that the stock AMC heads came with.
When you can get 310 cfm@.750 lift out of a 170cc port volume(which is what a good ported AMC iron head is) i dont think you will do any better by changing valve angle, and even the HLR, INDY,AND BREWER heads are made with the stock valve angle, so in my opinion it would probably not be any benefit to do.
Just my 2 cents.