781/049 Angle Milling

General engine tech -- Drag Racing to Circle Track

Moderator: Team

Post Reply
95ttoplt1
New Member
New Member
Posts: 13
Joined: Wed Oct 31, 2007 10:31 pm
Contact:

781/049 Angle Milling

Post by 95ttoplt1 » Sat Nov 04, 2017 11:14 am

We have a set of 781 that we are going to angle mill. First a little primer to save us all some time and effort as we have gotten nothing by time wasters in other forums.

Yes, we understand a piston swap can gain compression. Yes we understand aluminum after market heads are available. We understand the tertiary effects of the ANGLE milling(intake face, exhaust face, PTV clearance, Pushrod clearance, dowel location and depth etc). We understand there are factory closed chamber heads. So save yourself some typing. WE KNOW :D

Not to be rude, but I don't care that you flat milled your heads. Or angle milled a different casting than what we are asking. It seems reading comprehension is a super power these days hahaha

With that being said what we are looking for is

1. How much you were able to successfully ANGLE mill off a set of 781 or 049 heads and what intake valve size was used. Expressed in Thousandths off the intake and exhaust side, or in degrees.

2. How small you were able to get the chambers in CC.

Please guys I have asked in a couple different places and the most common answers are "I milled .040" off my heads and it dun runs good", "I had my AFRS angle milled and I love it" or "I stroked my BBC and got my compression up". Please don't be that guy. None of these are helpful responses, or even address the topic.

I'm hoping the crowd here is above such responses.

Carnut1
Guru
Guru
Posts: 3232
Joined: Tue Jun 11, 2013 6:32 pm
Location: Melbourne fl.

Re: 781/049 Angle Milling

Post by Carnut1 » Sat Nov 04, 2017 11:39 am

Truth is depending on exactly how high the valve seats are in the heads and the diameter of the intakes valves I do not think anyone can give you a 100% accurate number. I have seen these cut right to the intake seat. Doing so will lose some flow. 2.3" intakes can have less of a cut than stock 2.06" valves. By the way I am from NY so I love the attitude. Welcome to ST, giving more specs on combo and expected results will get you the info you seek. This board has very talented members. I personally would like to know the flow numbers you have on these at this point. Thanks, Charlie
Servedio Cylinder Head Development
631-816-4911
9:00am - 9:00pm EST

95ttoplt1
New Member
New Member
Posts: 13
Joined: Wed Oct 31, 2007 10:31 pm
Contact:

Re: 781/049 Angle Milling

Post by 95ttoplt1 » Sat Nov 04, 2017 11:44 am

Carnut1 wrote:
Sat Nov 04, 2017 11:39 am
Truth is depending on exactly how high the valve seats are in the heads and the diameter of the intakes valves I do not think anyone can give you a 100% accurate number. I have seen these cut right to the intake seat. Doing so will lose some flow. 2.3" intakes can have less of a cut than stock 2.06" valves. By the way I am from NY so I love the attitude. Welcome to ST, giving more specs on combo and expected results will get you the info you seek. This board has very talented members. I personally would like to know the flow numbers you have on these at this point. Thanks, Charlie
That is kind of what I was thinking. Measuring from the deck to the outer edge of the intake seat and then doing the trig.

Sorry, really no attitude, just frustration! Sometimes we find great info online from very intelligent people who are willing to share. It seems lately, more often than not, we just get people that like to flap gums regardless of the topic.

peejay
Guru
Guru
Posts: 1213
Joined: Tue Aug 10, 2010 9:16 pm

Re: 781/049 Angle Milling

Post by peejay » Sat Nov 04, 2017 11:49 am

95ttoplt1 wrote:
Sat Nov 04, 2017 11:44 am
Carnut1 wrote:
Sat Nov 04, 2017 11:39 am
Truth is depending on exactly how high the valve seats are in the heads and the diameter of the intakes valves I do not think anyone can give you a 100% accurate number. I have seen these cut right to the intake seat. Doing so will lose some flow. 2.3" intakes can have less of a cut than stock 2.06" valves. By the way I am from NY so I love the attitude. Welcome to ST, giving more specs on combo and expected results will get you the info you seek. This board has very talented members. I personally would like to know the flow numbers you have on these at this point. Thanks, Charlie
That is kind of what I was thinking. Measuring from the deck to the outer edge of the intake seat and then doing the trig.

Sorry, really no attitude, just frustration! Sometimes we find great info online from very intelligent people who are willing to share. It seems lately, more often than not, we just get people that like to flap gums regardless of the topic.
I zero decked a 301 Pontiac once and it would pull 100mph with a lot of pedal left...

Just kidding. I understand your frustration and it's a lot of why I don't bother asking questions a lot of times!

CGT
Expert
Expert
Posts: 849
Joined: Sun May 10, 2009 12:29 pm

Re: 781/049 Angle Milling

Post by CGT » Sat Nov 04, 2017 11:55 am

http://www.mjpsoft.dk/port_area_instructions.html

Programs such as these can get you there. Rick360 on here is very familiar with them. He has calculated a couple for me and it turned out a very accurate prediction.

Frankshaft
Pro
Pro
Posts: 436
Joined: Sun Jul 05, 2015 6:01 pm

Re: 781/049 Angle Milling

Post by Frankshaft » Sat Nov 04, 2017 12:07 pm

I have done a 0-.100 angle mill. I am pretty confident, if you wanted to, you could probably do 0-.150 maybe .200. If it gets into the intake seat, bfd, recut it and sink it in a bit, blend chamber accordingly. A lot of it is simply trial and error to figure it out. There is no 100% cut in stone way to do it. Remember, you don't have to cut all the way across the head. From your post, your familiar with everything that will change, and need to be "corrected". Creativity and common sense come into play if your trying to max it out. Is this something you have to farm out? Or can you do it your self? Because that can make a big difference, angle milling is involved and sort of a pain in the ass, if your not getting paid for your time. Most guys hate doing it, because of all the extra involved that most don't understand, and don't want to pay for it.
Last edited by Frankshaft on Sat Nov 04, 2017 12:17 pm, edited 1 time in total.

95ttoplt1
New Member
New Member
Posts: 13
Joined: Wed Oct 31, 2007 10:31 pm
Contact:

Re: 781/049 Angle Milling

Post by 95ttoplt1 » Sat Nov 04, 2017 12:17 pm

Frankshaft wrote:
Sat Nov 04, 2017 12:07 pm
I have done a 0-.100 angle mill. I am pretty confident, if you wanted to, you could probably do 0-.150 maybe .200. If it gets into the intake seat, bfd, recut it and sink it in a bit, blend chamber accordingly. A lot of it is simply trial and error to figure it out. There is no 100% cut in stone way to do it. Remember, you don't have to cut all the way across the head. From your post, your familiar with everything that will change, and need to be "corrected". Creativity and common sense come into play if your trying to max it out. Is this something you have to farm out? Or can you do it your self?
We are doing it in house.

When you say we don't have to cut all the way across. Can you explain that a little better? If we didn't come to zero at the intake face/deck intersection wouldn't that leave a peak longitudinally in the deck surface?

Thanks for the reply! refreshing to have a on topic response :)

Frankshaft
Pro
Pro
Posts: 436
Joined: Sun Jul 05, 2015 6:01 pm

Re: 781/049 Angle Milling

Post by Frankshaft » Sat Nov 04, 2017 12:22 pm

Basically, you can stop once the head gasket will seal the water. The part that hangs off into the lifter valley, is just hangin in the breeze so to speek. There will be a slight gap on the corners that you just fill with the right stuff gasket maker. About .007/cc. You will still have to correct the intake face angles.

95ttoplt1
New Member
New Member
Posts: 13
Joined: Wed Oct 31, 2007 10:31 pm
Contact:

Re: 781/049 Angle Milling

Post by 95ttoplt1 » Sat Nov 04, 2017 12:29 pm

Frankshaft wrote:
Sat Nov 04, 2017 12:22 pm
Basically, you can stop once the head gasket will seal the water. The part that hangs off into the lifter valley, is just hangin in the breeze so to speek. There will be a slight gap on the corners that you just fill with the right stuff gasket maker. About .007/cc. You will still have to correct the intake face angles.
Awesome, just the info I was looking for.

So a .100" angle mill would cut 14.28 cc? Does that sound right?

Thanks so much for the info.

utmost
Member
Member
Posts: 93
Joined: Mon Jun 27, 2011 10:01 pm

Re: 781/049 Angle Milling

Post by utmost » Sat Nov 04, 2017 6:07 pm

I agree with you, when we ask a simple question like yours and the know it all's ask why are you doing it that way, wouldn't it be easier to do such and such and this and that. that being said I have angle milled lots of heads with good results but it is a lot of work.

ProPower engines
Guru
Guru
Posts: 6860
Joined: Sun Jan 21, 2007 1:16 pm
Location: VICTORIA BC CANADA

Re: 781/049 Angle Milling

Post by ProPower engines » Sat Nov 04, 2017 8:10 pm

When it comes to angle milling BBC heads as mentioned the part of the head gasket that just touches the valley area is not an issue. It makes it easier to get the head milled down faster then cutting the whole head and leaves the port bottoms untouched making the port work easier.
Un MLS type of gasket works better when using sealer on the valley area of the gasket to seal. I have used the composition Felpro gaskets but they seem to weep oil in a short time at the rear of the engine.

I rough in the Valve job then CC the heads to make sure I am close on volumes between the heads and measure the valve to deck clearance. I then compare the 2 heads and alter as needed to get the balance before machining. That way any touch ups will be the same amount on both heads.
Real Race Cars Don't Have Doors

95ttoplt1
New Member
New Member
Posts: 13
Joined: Wed Oct 31, 2007 10:31 pm
Contact:

Re: 781/049 Angle Milling

Post by 95ttoplt1 » Sat Nov 04, 2017 8:30 pm

ProPower engines wrote:
Sat Nov 04, 2017 8:10 pm
When it comes to angle milling BBC heads as mentioned the part of the head gasket that just touches the valley area is not an issue. It makes it easier to get the head milled down faster then cutting the whole head and leaves the port bottoms untouched making the port work easier.
Un MLS type of gasket works better when using sealer on the valley area of the gasket to seal. I have used the composition Felpro gaskets but they seem to weep oil in a short time at the rear of the engine.

I rough in the Valve job then CC the heads to make sure I am close on volumes between the heads and measure the valve to deck clearance. I then compare the 2 heads and alter as needed to get the balance before machining. That way any touch ups will be the same amount on both heads.
Sounds like a good plan! Thanks!

User avatar
Baprace
Guru
Guru
Posts: 1585
Joined: Sun Aug 06, 2006 4:57 am
Location: Henrietta NY 14623

Re: 781/049 Angle Milling

Post by Baprace » Sun Nov 05, 2017 12:51 am

when you angle mill .000 - .100 you will get approx 75% +- CC's , you don't get 100% untill the cut has completley covered the chamber, then you can figure approx .007 per CC.

Post Reply