What did stock 197 HO heads flow?
 

Just curious what the 197 HO heads flowed stock. Also while we're at it, Ram Air IV too. How did these stack up against the D-ports like 670's, 13's or 6X? When I got ready to do my 455 street motor, I had the 197's, 13's and 6X to choose from. I chose the 197's just so my 69 GTO would resemble a Ram Air IV with the H-O intake and round ports.

http://www.wallaceracing.com/ultimatehead.htm

note all testing was done at 12"

I'll see if I can dig up some numbers of a friends set we did with several others. I can tell you un touched flowed much better than D ports.

My 197's flowed 243 cfm on the intake and 184 cfm on the exhaust at .500" lift/28" H2O

How about flow numbers from a stock set of SD heads? Will that help?

INTAKE

Lift #2 #4 #6 #8 AVG
0.050 35 35 35 35 35.0
0.100 68 69 68 69 68.5
0.200 136 136 136 135 135.8
0.300 194 193 195 196 194.5
0.400 215 214 222 219 217.5
0.500 228 228 235 231 230.5
0.550 233 237 238 238 236.5
0.600 236 237 241 239 238.3
0.650 239 240 246 245 242.5
0.700 243 243 249 247 245.5


EXHAUST

Lift #2 #4 #6 #8 AVG
0.050 36 28 26 30 30.0
0.100 68 63 61 65 64.3
0.200 113 111 110 109 110.8
0.300 146 142 142 138 142.0
0.400 172 168 169 152 165.3
0.500 178 175 177 158 172.0
0.550 184 181 179 159 175.8
0.600 184 181 181 160 176.5
0.650
0.700

This may help too.

http://www.classicalpontiac.com/qa7/...s&number=66687

Good stuff. Thanks a lot. My 197's flow around 235 at .500. I had always assumed they had had some work to them. I guess looking at these numbers they haven't had much work if any.

Rocky good statements on the guy who denies they flow better. I have a non Superflow bench single orificeand EVERY round port head has flowed better than a D port in the same condition(stock, mild porting).

I found a signifigant improvement on the RAIV heads using a flat valve vs their tulip design also.The HOs come with a flat valve.

Rocky I can't find access to it what rpm range were peak TQ and HP for factory round port 455s and also similar low compression D port 455s with teh same cams?

My 197s have not been flowed just raced.The engine is 9-1 comp 455 and in a 69GTO,11.27 @116mph.Dan Whittmore ported them and thought they were in the 260 range,maybe 265.Its tough to get more out of them as the valves are shrouded as compaired to a RAIV.
I should be able to get the car in the 11.15 to 11.0 range this season.Maybe high 10s.

Sorry for the delay, Skip. The RAIII (d-port) engines peaked around 5000/3500 (hp/tq, respectively). The RAIV engines peaked around 5500/3800. So on the 400, the larger round port heads and cam caused HP to peak roughly 500 rpm higher.

The 455 engines had remarkably lower peak points, but were affected similarly. The d-port 455 engines peaked around 4000/2800 (hp/tq, respectively), while the round port 455s peaked around 4400/3200. The HO's 068 cam wasn't exactly "large" for a 455, so we might speculate that the 400 rpm difference in hp/tq peaks, could be directly related to the larger ports.

For the record, I do know that Pontiac's engineering dynos ONLY recorded only TQ numbers, and horsepower mathematically calculated from it at all points.

Thanks Rocky- I think the 400s are really not an apples to apples as the 041 cam is much bigger than the 068 or 744. Those that have tried it in a street 400, especially lower compression know what it does. But even then the 5500 peak isn't a high rpm motor.

Even the D port 455s had a smaller 067 compared to the 068 with almost 15 degrees more seat duration and 9 degrees more overlap. So bigger cam and bigger ports and 10 HP more for only 400 more rpm in 71, 50 HP in 72. Interesting the big difference between 71 and 72 in HP when they made the switch from gross to net HP. Especially considering that the 70 455s with 64 heads had the same HP with the 067 or 068 cam-that doesn't make much sense to me, and only 10 HP less for the small valve 15 head 067 455.

The 73-74 SDs with the even bigger ports and a bigger cam(like the 744 28 degrees more intake duration and 22 degrees more overlap) picked up 50 HP.

So to make more HP based of a torque measurment the torque measurement must have been higher also.

OK some flow numbers same day we flowed these @ 10" multiply 1.67 for 28" numbers
#96 unported(identical numbers for an unported 6X-8)
0.1 47
0.2 81.6
0.3 100
0.4 110
0.5 113
0.6 115

197 unported

0.1 51
0.2 87.7
0.3 108
0.4 119
0.5 124.4
0.6 126.5

mildly ported 72 HOs-on a friends Formula now that was just in HPP
0.1 49
0.2 82.6
0.3 110.6
0.4 128.5
0.5 131.6
0.6 131.6

stock 614 flat valve-better low lift than tuliped higher lift the same
0.1 53.7
0.2 86
0.3 116
0.4 121
0.5 127
0.6 125.6

Thanks. Thats what I was looking for. I had Butler ckeck one cylinder on my 197's and they flowed 234 at .500 so they have had some work done to them. I'm putting them on a street car so they should work pretty well.

every day i kick myself for selling off all my roundport stuff a few years ago.
****!!!!!!!!!!!!!!!
hi skip.

I've got a 73 SD intake I'll sell you at E bay prices:):)

My friend Joe's yellow 72 HO Formula was recently in HPP that has those ported heads on it. Hasn't been to the track with it. I think Butler recommended a Comp XE 268 cam for it since it is mainly street.

rotflmaof!!
the day i change intakes from the 'ram is the day i'm buried and that's cause i'm taking it with me!

a 455 with stock D-ports will stop revving at 5200 rpm with an 068 type cam. falls flat on its face. FWIW, all dynos only measure torque, and calculate HP from it using math. even the most modern. HP is more or less, a bullschit number.

unfortunately, flow numbers at anything less than 28", can be misleading, and give an incomplete picture. here's why- 2 different heads that visibly have dramatic differences in port shape, valve size, port size, can flow the same at lower pressures. as the pressure is increased towards 28", that's when the differences show up, and a good port starts to flow more. beyond 28", there's not much difference. and that's how the 28" standard was discovered, by farmer cut and try method, by Smokey Yunick, with back to back dyno tests on the same heads to correlate. i.e. if the head flowed more, he double checked and verified it on the dyno, as making more HP too.
He laboriously took different ports and flowed them at increments from very low pressure to very high pressure, and found the sweet spot where the flow numbers reflect real HP gains on the dyno, and a good flow number therefore meant a good port. that pressure drop is 28". numbers at 12" can't be relied on as confidently. reason being you may have a head that flowed average to all the others at 12", but it would really take off at 28". that's the pressure drop that correlates with more HP on the dyno, as the flow numbers increase.
this is also where the late Pete McCarthy dropped the ball, when he did the Pontiac Ultimate Cylinder Head articles on HPP decades ago. Had he insisted flowing the heads at 28", that would be one heckuva an achievement. but no one is perfect. It was one of his few errors as a Pontiac journalist and writer and historical information. That's because Pete never read Smokey's book, Power Secrets. If you don't commit that to memory, you're a babe lost in the woods. They're all V8 engines breathing the same air on the same planet. Smokey ran Pontiacs in NASCAR from 1958-62 and dominated with them, and that's why. He had already built hos own flow bench and was using it and his dyno, on the Pontiac heads and engines, which at the time were the SD389/SD421 configuration. He was working with Pontiac engineering, advising and telling them what the engines needed, to be competitive in NASCAR. That's where the SD421 heads came from, and why the 980 heads were as good as they were.

If you go to the Stan Weiss site under the Pontiac listing you will see flow numbers I supplied to him many years ago on a 191 casting that all I did was apply a 3 angle valve job with a very deep 60 bottom cut , the OD of the 30 seat was maxed out, and the 15 top cut was intentionally held to .025"

The numbers at .200" and .300" are substantial!

Flow@28"

.100". 88

.200" 160

.300" 199

The 455 HO and Super Duty engines were race horses with the reigns pulled back tight.

The 068 cams was WAY too small for one and the engineers knew it. Problem is that the long overlap of the 041 cam made it next to impossible to get them thru emissions.

Below is a cam I used in a 1973 Super Duty engine built here, and the dyno chart. It clearly shows great potential for making power, but even with a modern roller cam profile having 230/236 @ .050" specs it's still leaving a LOT of power on the table.

Look at the cams Nunzi and HO Racing recommended for them sometime, althought they look like a LOT of camshaft on paper they are what was needed to bring out the true potential of those engines......IMHO.....

https://forums.maxperformanceinc.com...1&d=1661425455

https://forums.maxperformanceinc.com...1&d=1661425455