Anybody every play with or run a 576 head

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in stock elim, have to run stock angles on seats and valves 45 Deg.
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That was probably the case when you tried the heads, but now any valve job is legal.

Whatever came out of the MP box when I tried them in 1995.......whether they were 308’s or 576’s..... they made a little more power than the equally prepared 596’s did on those oval track 318’s I was building at the time.
 
rules state, stock angles only, use to be 3 angle on seats, now can have more, the valve face and seat in head must be at stock angles, super stock requires stock angles also. need to read rules, ok
 
Second to last sentence:

From 12/4/2019
SECTION 11A: STOCK, ENGINE: 1, CYLINDER HEADS (Page 3)

Must be correct casting number for year and horsepower claimed, per NHRA Technical Bulletins or NHRA accepted. Porting, polishing, welding, epoxying and acid-porting prohibited. Combustion-chamber modifications prohibited. Cylinder heads are additionally restricted in that they must retain original-size valves at original angles +/- 1 degree and must be able to hold original cylinder-head volume per NHRA Specifications. Runner volumes may not exceed the current Super Stock cylinder-head volumes as listed on www.NHRARacer. com. Regardless of the poured volume measurement, any modifications to intake or exhaust runners prohibited. Any evidence of modifications from the original castings will be grounds for disqualifications as determined by NHRA in NHRA’s sole and absolute discretion. Any aftermarket steel valve permitted, must retain stock head and stem diameters. Only engines OEM-equipped with sodium-filled valves may use sodium-filled replacement valves. Titanium prohibited. Hardened keepers permitted. Lash caps prohibited. Valve-diameter tolerance: +.005-inch or -.015-inch from NHRA Specs. The following are prohibited: spark-plug adapters; any grinding in ports or combustion chambers; removal of any flashings; sandblasting or any other modification to cylinder head; any film coating of intake and exhaust runners; any film coating of combustion chamber. Runners and combustion chamber must retain OEM appearance. Final acceptance as determined by NHRA in NHRA’s sole and absolute discretion. External modifications prohibited. Intake side of head may not be cut into any part of valve cover bolt holes. Valve-cover bolt holes must remain unaltered and in their original location. Intake manifold bolt holes must remain unaltered in their original location. Heat riser passage may be blocked from intake manifold side of cylinder head. Blocking passage down in valve pocket prohibited. The following are permitted: polylocks, jam nuts, screw-in larger-diameter rocker studs or pinned studs, bronze-wall valve guides, cylinder head studs. Valve spring umbrellas optional. Cylinder head may have all of the seats replaced. Any valve job permitted, O-ringing prohibited. Exhaust plates prohibited.
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The part about the original angle is in reference to the angle of the stem...... 15*, 18*, 23*, etc...... not the seat angle.

The valve job rule has been this way for several years now.
 
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just had a conversation with a fellow, that builds stock elim and s/s heads, stock requires stock seat angles, 45 deg. he was told by nhra teach that has not changed !!!!
 
I’m not going to argue with you about it any more.

If you looked at the head rules for stock in every year rule book for the past several years...... you would see that one year the wording for the seat angles was removed.
There is a reason they did that. It’s so they don’t have to check it in tear down anymore.

The only reference in the current rules that pertains to the valve job at all states that any valve job is permitted.
There used to be wording specifying the stock seat angles.
They removed it.
The rule changed.
Like so many other rules in stock have over the years.
 
What ever you can get away with....
 
pishta said:
I have a set on my stroker. have not ran it yet. The PO did some bowl blending and tried to polish the intake port, not sure if he helped them or hurt them. I didnt know if they were a performance head, thought it was just a '308' replacement version. wasnt alot of info on them last time I looked...5-6 years ago.
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Nope, my mistake, they are 974's hogged out. Not much of a short side radius on these exhaust ports....PO gutted the floor! Pretty rough port match too. I didnt touch these, just got these 2.02's for a song.

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pishta said:
Nope, my mistake, they are 974's hogged out. Not much of a short side radius on these exhaust ports....PO gutted the floor! Pretty rough port match too. I didnt touch these, just got these 2.02's for a song.

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There’s proof that everyone should not touch porting burrs. I think we have all done some type of porting work we shouldn’t have but he hit every base on that job.
 
I got a pro ported set to replace these. Much cleaner. This was a hack job I agree. I think he was under the impression that the bigger the volume of the port the better it would flow. We know better, shape and flow is where its at. One of you porters should mark up the errors in this hack job and make it a sticky on what NOT to do when porting. You got my permission to repost and flame it as I take NO credit for doing this, only buying them for $100 a pair as the 2.02 valves and dampered springs were worth that much.
 
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pittsburghracer said:
There’s proof that everyone should not touch porting burrs. I think we have all done some type of porting work we shouldn’t have but he hit every base on that job.
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That's me!

I have a set of clean 576 heads if anyone is interested in seeing more pics. Have the "308" porting templates too but don't worry John, I have not broken out the burrs on these yet!
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rmchrgr said:
That's me!

I have a set of clean 576 heads if anyone is interested in seeing more pics. Have the "308" porting templates too but don't worry John, I have not broken out the burrs on these yet!View attachment 1715543272 View attachment 1715543273 View attachment 1715543274 View attachment 1715543275 View attachment 1715543276
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Hey I think every car guy should try it at least once, on a scrap head. You may fall in love with learning the art and enjoy the results and money saved. I know I did.
 
rmchrgr said:
That's me!

I have a set of clean 576 heads if anyone is interested in seeing more pics. Have the "308" porting templates too but don't worry John, I have not broken out the burrs on these yet!View attachment 1715543272 View attachment 1715543273 View attachment 1715543274 View attachment 1715543275 View attachment 1715543276
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Whatever you do, do not make the exhaust port bigger. It’s too big to start with and the shape is horrible. Take the bump out of the roof, and remove the smog bump if there is one and do your best to get something like a radius on the short turn.
 
pittsburghracer said:
Hey I think every car guy should try it at least once, on a scrap head. You may fall in love with learning the art and enjoy the results and money saved. I know I did.
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It was enjoyable at first, went at it full bore making chips like crazy. But later as I was sipping my well-earned beer I realized I had to duplicate the effort 15 more times! That was an epiphany, kinda like "aaaahhhh, that's why these head porter guys make the big bucks..."

I definitely went too far in some places, the head I worked on will need to be cut for larger valves for starters.

Plus my nice Dumore grinder seems to to have crapped out on me. Rainy day project when all my other junk is squared away.

In any event, I would like to see how well some nicely massaged 576 heads would perform in an appropriate application. I think they are good for a stout street engine if you endeavored to use ancient tech iron heads.
 
I realized I had to duplicate the effort 15 more times! That was an epiphany, kinda like "aaaahhhh, that's why these head porter guys make the big bucks..."
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Now you know why I like to get “the most flow..... for the least work”

Sometimes the big effort is required....... but..... sometimes “the most for the least” will get you where you want to be.
 
PRH said:
Now you know why I like to get “the most flow..... for the least work”

Sometimes the big effort is required....... but..... sometimes “the most for the least” will get you where you want to be.
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And that's why "we" get paid the big bucks for knowing stuff like this---LMAO. J.Rob
 
RAMM said:
And that's why "we" get paid the big bucks for knowing stuff like this---LMAO. J.Rob
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At some point you have to pay the piper.


Not trying to get off the original 576 topic but since we are talking about rookie porting jobs, here is my first attempt on a set of 452s.

I showed these pics to Dwayne last year, he said obviously he wouldn't be able to tell what they flow just by looking at a fuzzy picture on the screen but reading between the lines of his responses it seemed like he was saying it might be worthwhile finishing them at least to know what the results of my efforts were.

Like said, these will need larger valves. I will finish them at some point.
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rmchrgr said:
At some point you have to pay the piper.


Not trying to get off the original 576 topic but since we are talking about rookie porting jobs, here is my first attempt on a set of 452s.

I showed these pics to Dwayne last year, he said obviously he wouldn't be able to tell what they flow just by looking at a fuzzy picture on the screen but reading between the lines of his responses it seemed like he was saying it might be worthwhile finishing them at least to know what the results of my efforts were.

Like said, these will need larger valves. I will finish them at some point.
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"Looks" really good, I like the '452's even though they have a non existant S.S. they still can make great power when ported. You may be a little thin in some spots in bowl by the looks of it. I bet they flow 265 ish, maybe a bit more. J.Rob
 
RAMM said:
"Looks" really good, I like the '452's even though they have a non existant S.S. they still can make great power when ported. You may be a little thin in some spots in bowl by the looks of it. I bet they flow 265 ish, maybe a bit more. J.Rob
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Thanks.
 
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