From the head surface what angle do you set to "angle mill" a set of 350 SBC heads?

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Be Blessed,
Doc

it depends on how heavy the casting is.

New World Products Heads

There has to be an angle at which to mill for minimum combustion chamber volumn on any sbc 350 head. What would be the difference if the head was flat milled .030 or .000 prior to angle milling?

Thanks for your time & advice.

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Be Blessed,
Doc

Angle milling causes many problems. Youmust be sure that this is the route you want to go. There is more machining required than just angle milling.

The angle you go will depend on how much you can safely mill of the particular head. Generally you can get away with taking 0.100" off the exhaust and take very little off the intake side. Once than is done, the bolts will not go in because the holes are now at an angle. You wil need the have the holes elongated and refaced to avoid stressing the bolts. Another option is to have studs necked down to a smaller size, but the holes must still be refaced so the nuts seat straight. You will also have to mill the intake to match the angle of the heads and have an intake that will only work with those heads.

IMO angle milling is a very poor way to increse compression. It is usually done in race classes that require the original heads.

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www.grapeaperacing.com (http://www.grapeaperacing.com)

Thank you very much. I know this sounds ignorant however I have been building race motors for 42 years but I have had a machine shop do my head milling and never asked what angle he used to cut the angle milled heads. I do realize all the other things I need to do to make them work.

You are correct that we have to use stock type heads & no pop-up pistons. We have to do all we can to make compression. deck block - mill heads, etc.

Thanks for your suggestions.


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Be Blessed,
Doc

the angle will depend on how thick the deck surface is (as stated earlier),the ONLY benefits of doing this are:the DECREASE in chamber volume is greater than a "flat" mill could ever acheive ,and the valve (angle) after angle milling has a less tendency to be shrouded by the cylinder on larger valves and higher lifts.it is pretty costly and not practiced alot because of all the machine work that is involved(as stated earlier).the angle will always depend on deck thickness and head bolt hole thickness on the exghaust side.thats why your machinist never asks you the angle you want,he asumes you want to go the max posible under the conditions of the head.

Ok - That is exactly what I want to do. Now where do I start if I know the deck thickness.

Thanks again.

Doc,
As others have said, the angle just depends on how much volume you want to reduce the chamber size. I would like to add however, that we have angle milled a BUNCH of small block heads for the local dirt track guys and have never had any problems with bolt or intake fit. If the job is done correctly, there will be no problems. You have to mill the intake side of the head back to the corect angle, and spot face the bolt holes, but everything else works fine.

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Bill Koustenis
Owner
Advanced Automotive Machine
Waldorf Md
1971 Chevelle "Heavy Chevy" original owner
1973 Z-28 ..one family car...Brother bought it new in 73

Doc,

I think what the others are trying to say is when angle milling heads, the machine shops always machine a certain amount off the exhaust side of the head, and angle the cut so that no material (or very little) is taken off the intake side. That is why sometimes you will see angle mill specs written as 0-100, or 0-60. That means 0.100" or 0.060" is taken off the exhaust side, and 0" is taken off the intake side. Because of this, the more material you take off, the more off an angle the head is milled at. That is why the machine shops never mention the angle. They only want to know the amount you want to take off or the amount of chamber reduction you want. Hope this clears it up.

As for how much you should take off on the exhaust side, depends on the minimum deck thickness your machine shop prefers. If the heads are new, you should have NO problem going 0-100 (0.100" on the exhaust side).

BTW, nice to see another okie on the board. Are you racing ovals now? Giving up on the drags or what? You probably don't remember me, but I race a brown 81 Z-28 at Noble. It was running low 11's, NA small block, about 4 years ago. Still haven't got it back running yet, but hoping to break into the single digits. Take care.

Shane

I believe I remember you well. You ran Hoosier tires you bought from me. You & your dad were at the track together usually. Yes I am doing a lot of oval track stuff now. I build the motors for Robert's Auto in Noble (3 cars).

Nice to talk again.

Be Blessed,
Doc

Oh Yeah - Thanks for the info!!

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Be Blessed,
Doc

<BLOCKQUOTE>quote:</font><HR>Originally posted by BillK:
Doc,
I would like to add however, that we have angle milled a BUNCH of small block heads for the local dirt track guys and have never had any problems with bolt or intake fit. If the job is done correctly, there will be no problems. You have to mill the intake side of the head back to the corect angle, and spot face the bolt holes, but everything else works fine.

<HR></BLOCKQUOTE>

I have yet to see a 0-100 cut or more not require machining the long bolt holds in the head. The bolts will go in, but when the bolt necks up near the head, it will contact the side of the hole. This "can" work, but I do not like putting the side stress on the bolts. A 0-100 cut will move the tops of the holes about 0.055" toward the exhaust side. I have seen very few stock heads that have 0.055" extra room in the long bolt holes. It's not a big deal to clearance the holes to avoid any problems.

Generally for a stock racing class, I go 0-0.100" along with a 0.020" regular cut, and zero deck the block. You can get about 11.3:1 out of flat top pistons in a 350 this way.

I have angle milled a lot of small-block heads as well. More for stock classes of drag racing, and would not compromise head bolt strength by placing side loads on them.

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www.grapeaperacing.com (http://www.grapeaperacing.com)

Thank you so much for all your help. I believe that I can figure this rascal out now.

Have a wondeful holiday.

Blessings,
Doc

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Be Blessed,
Doc