[PAUL K]

Originally Posted by ponyakr

"... on a stock 670 head I got it to flow 225 to 228 cfm..."

So, you think Randi Lyn's '67 Stocker can run 10.50 or quicker, with no more flow than that ?

OR, do you think the heads have been "massaged" to flow more ? IF so, how much more ?

I understand about Stocker "tricks" & "set-up" to run quick. BUT, the engine still has to make a certain amount of power to run the big numbers.

SO, since this thread is about 670 head flow, there's no better place to include the 670 heads on an NHRA Stocker.

Aprox how much would heads have to flow in order for a 400 Pontiac engine to turn 8000 rpm ? Is that something you guys can calculate ?

Bryan Phillips also has a 10 sec '67 Bird Stocker. So, I assume his 670 heads also flow more than a non-ported factory stock set.

I have one for you; how fast do you think Mrs. Shipp's 400 would run in a stock 67 Firebird? Maybe assume a TH400 and the performance gear ratio.

[ponyakr]

"...what flow numbers are possible from a 670 head with professional CNC porting? "

When I went back I read this, I decided to check on the SD CNC porting deal.

To my surprise, SD no longer fools with iron heads. I suppose I'm the last to know.

http://www.sdperformance.com/listPro...?categoryID=53

I suppose he has much more than he can do, with just alum heads.

So, who now has the best CNC program for iron Pontiac heads ?

Butler says they do more Pontiac heads than anybody else in the world.

https://butlerperformance.com/i-2445...tegory:1234782

I suppose there are several members here who do hand porting. I assume most members know who these guys are. Any who wish to advertise their porting services can. Don't know who now does a lot of CNC Pontiac iron head porting.

KRE shows lots of alum head CNC porting. But there is no mention, specifically, of porting iron heads.

http://www.krepower.com/Pontiac%20Cylinder%20Heads.htm

Nitemare shows Pontiac iron head porting services. Not a recommendation. Just a possible source.

http://www.nitemareperformance.com/cylinderheads.html

Got this from a Google search.

https://headsandmanifolds.wordpress....-head-porting/

[mgarblik]

In a rules restricted class like NHRA Stock, you just have to work within them. The heads are so limited in flow, all you can do is open the valve as quickly as possible and keep it open as long as possible. Any duration allowed. You end up with rectangular cam lobes and hope for the best. Valve springs become super important. Lifters and cams don't last long.

[ponyakr]

Originally Posted by mgarblik

In a rules restricted class like NHRA Stock, you just have to work within them. The heads are so limited in flow, all you can do is open the valve as quickly as possible and keep it open as long as possible. Any duration allowed. You end up with rectangular cam lobes and hope for the best. Valve springs become super important. Lifters and cams don't last long.

Yeah, some of that's true.

BUT, those things alone won't produce the quick times SOME cars are posting.

Therefore, SOME Stocker heads fudge on the rules, therefore producing much more flow than the stock, as produced, ports will flow.

What I'm saying is NOT a secret. It's a well known fact that Stocker guys have been modifying head ports, for a long time, to increase flow.

My guess is that some of these guys got caught, back in the old days. But, I'm thinkin that nowadays, you'd have to have a really big, obviously enlarged or otherwise modified port, in order to provoke a DQ at an NHRA race.

I suppose they COULD check the ports really close & DQ a Stocker. But, somehow, at this point, I don't think they will. Could be wrong tho.

To me, it would be REAL interesting to get a good close up look at a stock, as cast, 670 head, right beside a head off Randi Lyn & Bryan Phillips' '67 Stockers. Might be rather "eye opening", especially to you guys who have done lots of Pontiac head porting, & are very familiar with 670 heads.

On the other hand, it might actually surprise me, if I could see no difference in the ports, at all. I'll never get that chance, & probably nobody else will, except those involved with the cars and/or head prep.

Lot's of the current Stock racers spend many thousands of dollars for heads that will flow enuff to produce the big numbers needed for class wins & nat records. As long as there are those willing to spend the big bucks, there will probably be guys who will build those heads.

BUT, thankfully, due to the breakout rules used for the rounds which are not same-class heads-up runs, maybe Stock Eliminator will survive for a while longer. Many of the Stock/SS guys HATE it when anyone likens their form of racin to bracket racing. Some will get downright nasty with anyone who even suggests a similarity. BUT, in spite of that, without the breakout rules, Stock/SS would probably not exist today. Only the super rich could win.

All the slower, really soft combinations would eventually disappear, & Stock/SS would become more of a "pro" class. NHRA could make most any combo completely non-competitive, with one hp factor hit.

But, as long as the breakout rule is in effect, any car that will pass tech & teardown, & can run it's index or quicker, it can win a race.

[i82much]

Originally Posted by ponyakr

"...what flow numbers are possible from a 670 head with professional CNC porting? "

When I went back I read this, I decided to check on the SD CNC porting deal.

To my surprise, SD no longer fools with iron heads. I suppose I'm the last to know.

http://www.sdperformance.com/listPro...?categoryID=53

I suppose he has much more than he can do, with just alum heads.

So, who now has the best CNC program for iron Pontiac heads ?

Butler says they do more Pontiac heads than anybody else in the world.

https://butlerperformance.com/i-2445...tegory:1234782

I suppose there are several members here who do hand porting. I assume most members know who these guys are. Any who wish to advertise their porting services can. Don't know who now does a lot of CNC Pontiac iron head porting.

KRE shows lots of alum head CNC porting. But there is no mention, specifically, of porting iron heads.

http://www.krepower.com/Pontiac%20Cylinder%20Heads.htm

Nitemare shows Pontiac iron head porting services. Not a recommendation. Just a possible source.

http://www.nitemareperformance.com/cylinderheads.html

Got this from a Google search.

https://headsandmanifolds.wordpress....-head-porting/

i’m not sure he always gets my sense of humor, but if i had a set of iron heads that i wanted ported I would PM steve25 and ask him if we could port them or, if not, who he would recommend. the guy seems to know his stuff.

[ponyakr]

Originally Posted by PAUL K

I have one for you; how fast do you think Mrs. Shipp's 400 would run in a stock 67 Firebird? Maybe assume a TH400 and the performance gear ratio.

Quicker than that same car with absolutely "as cast" ports, on otherwise identical heads, is my guess.

So, are you saying that the heads on her engine have absolutely "as cast" ports ? Hey, I'm asking. I don't know. There's no possible way I could know.

It's just my thinkin that these 1st gen Pontiac Stockers couldn't run low 10's with D-port heads, which have untouched, "as cast" ports.

Don't it take around 500hp or more to run these times/speeds ? Will a legal '67 Pontiac 400 Stocker engine make 500hp ? More ? How much ?

To me, these are legitimate questions. I don't have a clue how to calculate the answers. But, I assume that some here can.

[ponyakr]

Since I brought it up, I feel obligated to post a little more info about Randi Lyn & her '67 Bird Stocker. Here are some quotes from the article, linked below the quote.

"...Running at 3,210 lbs. (with driver) in D/SA (11.55 index), the Pontiac has run 10.40 at 124 mph. And when set up lighter for C/SA, it's run a best of 10.31 at over 125 mph...

Amazingly, the Poncho sings to 6,800 before she clicks the gears, and it buzzes across the stripe where no Pontiac should go—revving to 7,800-8,000 rpm!...

rated by Pontiac at 325 hp and factored to 338 hp by NHRA. It's meticulously prepared to take full advantage of the Stock Eliminator guidelines and produces north of 500 hp..."

https://www.motortrend.com/features/...1967-firebird/

The article was published back when she only had 4 nat event wins. I think she now has 7. But, I don't think she's married yet. So, she's still "Miss" Shipp, & has never been "Mrs. Shipp". LOL

There are lots of pics in the article. One of 'em shows that the engine does indeed have 670 heads. And I assume she revealed the 500+ hp number, because she's seen the dyno numbers.

So, bottom line is that she shifts @ 6800, crosses @, or very near 8000, makes over 500hp, & has run quicker than 10.50's.

She even provided the ET, top speed, & total weight numbers, so you guys who know how to calculate stuff can do your thang.

Randi Lyn seems like a real nice lady, and their whole racing operation seems to be 1st class. So, she & her Pontiac are a couple of my favorites.

But, with all that said, I still don't have a clue if those 670 ports are "as cast", or not.

Here's another article, with less technical info.

https://dragchamp.com/2020/nhra/stoc...ndi-lyn-shipp/

https://dragchamp.com/2019/nhra/stoc...-66-nationals/

https://www.facebook.com/rlshipp

[sdbob]

My exp with my stk parts SD455,35 yrs ago. Car weighs approx 3740. Heads were done by AHines Racing out of Lawrence burg Ind. He was doing engines for different Pontiac guys. Anyways I had some input from John Herslow.John said to run 4.56 gears. I tried them with basic slapper bars. Car was spinning,i tried adjusting shocks ex.just couldnt get good consistent times. So I put 4.10s in got car to 12teens at 110. Still not good. He had gone 11.70s. So we talked. He gave me a cam that he said went the fastest with,however he said car was popping through carb. I have cam but was afraid to use it. My point being you need all the dyno time, testing in car to find what works.Another you could estimate hp, work backwards car weight,mph get ball park figure for required hp. I do think heads are modified with acid to get the flow for the hp. I'm satisfied at my age if I was younger I would test different ideas. Automatic trans are in the $5k range I've been told,gulp! for me. Testing ,more testing.i will tell you for my SD that the qjet 2nd metering rods are very very thin,I picked up when I did that the engine wants fuel.

[PAUL K]

Originally Posted by ponyakr

Quicker than that same car with absolutely "as cast" ports, on otherwise identical heads, is my guess.

So, are you saying that the heads on her engine have absolutely "as cast" ports ? Hey, I'm asking. I don't know. There's no possible way I could know.

It's just my thinkin that these 1st gen Pontiac Stockers couldn't run low 10's with D-port heads, which have untouched, "as cast" ports.

Don't it take around 500hp or more to run these times/speeds ? Will a legal '67 Pontiac 400 Stocker engine make 500hp ? More ? How much ?

To me, these are legitimate questions. I don't have a clue how to calculate the answers. But, I assume that some here can.

My mistake I though she was married to Bo.

What you are asking in regards to the CFM it would take to run mid tens in her car is going to be tough to figure out. There is a whole lot more going on with the rest of the car than just what's under the valve covers (as you know). If you knew what the engine would run in a stock Firebird or known chassis it'd be easier to base line the power their engine is making.

I don't know enough about their combo to venture a guess. I'm certain, based on my past experiences is a lot of "class" racers seem to think ten horsepower that they paid $5k for is a better than ten horsepower they can buy for $500.... Regardless they do manage to squeeze a lot of ET out of their combinations. I'm glad a handful of them are flying the Pontiac banner with success after all these years.

[Formulajones]

Originally Posted by ponyakr

..

rated by Pontiac at 325 hp and factored to 338 hp by NHRA. It's meticulously prepared to take full advantage of the Stock Eliminator guidelines and produces north of 500 hp..."

https://www.motortrend.com/features/...1967-firebird/


There are lots of pics in the article. One of 'em shows that the engine does indeed have 670 heads. And I assume she revealed the 500+ hp number, because she's seen the dyno numbers.

So, bottom line is that she shifts @ 6800, crosses @, or very near 8000, makes over 500hp, & has run quicker than 10.50's.

]

Easy to figure. If it only weighs 3210 with the driver, that's pretty friggin light, then it only needs a little over 500hp to run mid 10's. That's a pretty light car so it doesn't surprise me to run those times with a 400 and 670 heads considering all the other tricks they do. Don't need a dyno to figure that out, but it's a rough guess. One thing for sure as Paul has already said, they know how to use every bit of power the engine puts out.

The rules state they aren't supposed to play around with the ports, but nothing about what they can do with valve jobs, seat angles, and valves.

I already stated how Paul improved the flow of the heads I sent him with just his valve job tricks. The flow sheets showed as much as a 30 cfm gain. I'm sure other engine builders that do a lot of NHRA builds have figured that out too. Work within the rules.

So for conversation sake, if a 670 head flows 220 cfm stock, theoretically you might find another 30 cfm just playing with certain valves and valve angles if you know what you're doing.

With the low lift cam having tons of duration (square lobes I mentioned earlier) to take advantage, I could see the engine making some decent HP, and HP is just a math equation of torque production. With that said, even more interesting is that I'd bet torque production would be better than most other engines of that size and that's what helps move the car down track.
Boy this kinda got way off subject, lol. But interesting.

[Formulajones]

There is also a reason why you'll see that Pontiac combo more often in stock NHRA type racing than most other Pontiac combos. Seems those 670 heads have something better about them than most other castings. I've heard that from a couple of Pontiac stock eliminator guys.

[ponyakr]

Originally Posted by Formulajones

There is also a reason why you'll see that Pontiac combo more often in stock NHRA type racing than most other Pontiac combos. Seems those 670 heads have something better about them than most other castings. I've heard that from a couple of Pontiac stock eliminator guys.

Now, there's something else that's real interesting.

I have only known of 2 Stockers & 1 Super Stocker that are running 670 heads, in recent history.

LOTS more Stockers running a '68 Bird, especially in this century. The NHRA hp factor for the '68 D-port head 330hp engine has always been very similar to the '67 hp factor, as far as I know. So, I'd say maybe the open chamber #16 & #62 heads might have just as much potential as the 670 heads. Is there info proving that the 670's are better ?

There have also been lots of 4X head '74's & 6X head '77/'78's, that have run strong in Stock & SS. Many more than '67's.

"...I've heard that from a couple of Pontiac stock eliminator guys."

Just out of curiosity, were those guys running 670 head Stockers ? Unless one of 'em was Bryan Phillips, I'd don't know of any other guy who has run a 670 head Stocker, in the last 10 years. If there is one or more, I'd like to have that info.

[PAUL K]

About forty years ago I sold a virgin pair of 670 heads to a gentleman from another State. He seemed all hot and bothered to get them. He had me send them to Ellison Race Engines, which if I remember correctly were in Cincinnati. About three weeks after sending them I get a call back from the gentleman wanting to know if I had interest in buying them back. He told me Ellison said they were nothing special.

[Jay S]

If Shipp’s car is set up down to the minimum weight for C/SA the car and driver weight should be 9 x 352 HP = 3168 lbs. It mph’s at about 120 mph. That indicates closer to 460 HP by the et calculators I use. Ball park number…Working the old super flow HP equation backward that is 221 cfm @28”. What that car does exceptionally well is that first 1/8 mile, that is usually where S and SS are quick, the quarter et is mostly made in the first 1/8th. That 10.50 ish et is quick for a 120 mph blast.

300 cfm shouldn’t be that difficult of number to hit if someone put in the work on a d port. I am not sure how easy it would be on a 670, IRC they are known to be stronger flowing at the lower lifts versus other d ports. Without flow numbers at all the lifts it is really really difficult to judge how well and how long they would work for racing or on the street. Maybe it flows 300 but it is at .8” lift, 300 sounds awesome but if the cam doesn’t even have .5” lift the car would likely be faster with stock heads. Lots of people have went over 300 cfm with d ports. But they look something like this photo of these D ports of a friends, ran deep into the 9s NA in a 3200 lb car….bad azzzz set of d port heads.

[ponyakr]

"...9 x 352 HP = 3168 lbs..."

Not sure where you got those numbers.

According to the Class Racer Info site, it looks like the current hp factor is 338hp.

http://www.classracerinfo.com/Engine...4&MAKE=Pontiac

9 x 338 = 3042 + 170(for driver) = 3212 lbs min weight for C class, if I punched in all the correct numbers.

She said that in C/SA it ran a "...10.31 at over 125 mph..."

She said that in D/SA it ran "...10.40 at 124 mph..."

9.5 x 338 = 3211 + 170 = 3381 lbs min weight for D class

So, maybe 124 mph @ 3380 lbs will give you guys the numbers you need to make a closer estimate of power ?

Guessing they probably ran at least 20 lbs or more heavy, to be on the safe side. So, I'd use an even 3400 lbs for the D/SA min weight, when punching in the numbers.

When I punched in 10.40 @ 124 mph @ 3400 lbs, the Wallace hp calculator shows somewhere between 596 & 506 hp. That's quite a range, so I don't know how accurate it could be. What online 1/4 mile hp calculators do you guys think may be fairly accurate ?

http://wallaceracing.com/hpcalculatorquarter.php

This calculator says it'll take 506hp to run 124 mph in a 3400 lb car.

https://racingcalcs.com/quarter-mile-calculator/

This one also says 506hp.

https://www.tciauto.com/racing-calculators

Same for this one. Apparently, several of these are using the same formula, which, according to this site, must be "HP = (MPH ÷ 234)³ × Weight".

https://www.gregraven.org/hotwater/c...p-from-qm.html

IF this formula is close to accurate, Randi Lyn's engine has to be makin a little over 500hp, minimum.

[tom s]

I agree with Steve on using ET to figure H.P. with NHRA cars.Use MPH.Tom

[Jay S]

You are correct Don, I was using the 67 400 RA rating and forgot to add the 170 lbs on for the driver and min rating weights. But the 120 mph was from when I watched the car go down the track, 120 to 121 was what I watched. From those better numbers you listed I come up with 528 hp, recalculating that is likely at most a 253 cfm head using the .26 super flow number. I doubt though that the .26 is correct, likely .28 or more on a stocker, I am guessing the head flow in the 230s. Can’t really compare stock and SS to other porting that does not have to meet port volume criteria for class rules.

X3 on using mph and not et

[ponyakr]

"... the 120 mph was from when I watched the car go down the track, 120 to 121 was what I watched..."

Yeah, with the NHRA hp police being on duty, at most big races, most of the quick cars sand bag, so their combo won't get a horsepower hit.

A quick search turned up a D/SA speed of 124.06 mph, for Randi Lyn, @ Indy, in August. She was more than a sec under, but had to settle for D/SA class RU. The D/SA winner was more than 1.2 under, which would have earned a hit from NHRA, this year. The US Nats race has been exempt in recent years, but not this year.

https://www.dragracecentral.com/DRCS...r2019#indextop

Look how even the quick cars were very careful to NOT go 1.2 under, this year.

https://www.dragracecentral.com/DRCS...r2021#indextop

At most races, a time of 1.20 or more under the index will get the combo an automatic hp hit.

I've read that some just add a bunch of weight. Some short shift. Some let off early. Some detune. Some use some combination of 2 or more of these methods.

So, Randi Lyn will not be running near as quick as the car is capable of, at MOST races.

Same goes for all the Stock/SS cars that can run 1.20 or more under.

[Stan Weiss]

It is hard to say what HP the car is showing because there are a number of things about the car we don't know. Based on my assuming somethings I get this using less than 500 HP. Shifting at 6800 RPM and 7997 RPM @ 1320 feet.

60 Foot ET = 1.2845
330 Foot ET = 4.0715
1/8 Mile ET = 6.5046
1/8 Mile MPH = 101.1140
1000 Foot ET = 8.6110
1/4 Mile ET = 10.4082
1/4 Mile MPH = 125.3550

Stan

[P@blo]

Originally Posted by Jay S

If Shipp’s car is set up down to the minimum weight for C/SA the car and driver weight should be 9 x 352 HP = 3168 lbs. It mph’s at about 120 mph. That indicates closer to 460 HP by the et calculators I use. Ball park number…Working the old super flow HP equation backward that is 221 cfm @28”. What that car does exceptionally well is that first 1/8 mile, that is usually where S and SS are quick, the quarter et is mostly made in the first 1/8th. That 10.50 ish et is quick for a 120 mph blast.

300 cfm shouldn’t be that difficult of number to hit if someone put in the work on a d port. I am not sure how easy it would be on a 670, IRC they are known to be stronger flowing at the lower lifts versus other d ports. Without flow numbers at all the lifts it is really really difficult to judge how well and how long they would work for racing or on the street. Maybe it flows 300 but it is at .8” lift, 300 sounds awesome but if the cam doesn’t even have .5” lift the car would likely be faster with stock heads. Lots of people have went over 300 cfm with d ports. But they look something like this photo of these D ports of a friends, ran deep into the 9s NA in a 3200 lb car….bad azzzz set of d port heads.

I picked up a pair of Butler ported 670 from a forum member here and took them in for new bronze guides and a valve job. The intake port shape is the same on my heads and looks a little square.

The machine shop indicated they flow a lot better than the 250cfm that I thought and called them a race head. Combustion chamber has been modified to an open back-woods modern version as well. The cc was 172 on the intake ports.

The 670 heads are pretty popular with guys so while they are just a normal D-port they can be a good head once modified. Something about the later cast heads have the larger combustion chambers that intrudes into the port turn.