During all the 428cj discussions IIRC it was Dennis K who mentioned the C8AX-C was the goal for the 427/390hp but it either wouldnt pass smog or drivability. So the good old 390gt/428cj cam was used instead.

C8AX-C is listed as "optional" for the 428CJ LOL but that was just to make it NHRA Stock legal.
Same grind is the stock 70-71 429CJ cam. A little rumpier than the 428CJ cam but liveable even in winter BTDT.

Per Muscle Parts it adds 13-15hp vs the 270-290 428CJ cam, and I believe that having run a couple of em.
C8AX-C is 220-230-116 at .050, Ken at Oregon used to like to grind about 220-230-112 for a little more kick. And a rougher idle.

Here is a PDF of that article from HR. You should be able to download a copy in the upper right.

https://drive.google.com/file/d/1XnaSK1KeiNPgaosDDv1xhQSBBdGG4sGP/view

Awesome! I didnt have thi article.
Looks like the 8v didnt exist yet, and the 4v just says "over 600hp" which jives with the later 616hp rating.
Doesnt say if that was in A-Curve condition though (steel headers and blueprint).

Recall from Jay's testing, on a good old 427 circa 400-450hp, the long iron is about as good as steel headers.
But at 600+ hp that changes, so the configuration still matters for that 616hp and 657hp rating.

Cool to see the old HiRiser data.
Not sure how you'd count the T-Bolt out of Dearborn Steel Tubing, but the 64 LWG Lightweight Galaxie was a real assembly line 427 HiRiser car.
(all 100 of em)
Cast iron exhaust manifolds like a real civilized car & dual exhaust too.

The factory cam was identical to the C3AZ-K 427-8v cam, 324-324 244-244 114.5 LSA .525 .525 gross lift.
The only difference for the HiRiser C4AE-B cam was a much closer LSA=106.

Totally streetable Sunoco 260 grocery getter except maybe in Michigan winters back then.
Gonkulates right around 500hp with the factory iron exhaust in a nominal build.

Thanks Jay.
Do you know the source paper or article for that 8v Torq=575 Power=657?
Of course it gets repeated everywhere now but wondered how it originated, clearly not the SAE paper.
There were some other early SOHC articles but I dont have any that mention the 657hp.
Wondering how they got it (iron exhaust vs headers, prep, etc)

This classic thread seems the right place for this question since Jay you noted the Cammer SOHC specs at 4v=616hp, 8v=657hp.
Nobody on fordfe.com seems to know.
See link below with specs.
But also, note that in the original SAE 650497 paper, the specs at the back say
Torq 515 at 3800
Power 616 at 7000
But then lists TWO 4v carbs.
The graphs arenc conclusive either, they do show a peak about 620hp for the 8v in Figure 42, but clearly it's not even near peaking.
Peak 8v torque looks a lot more like 530 vs 575 in the Motor Trend link below.
Any idea of the real factory SOHC ratings & how they were obtained? A-Curve conditions maybe (blueprinted engine, steel tube headers etc?)

********************************************************************************************************************
I was searching for a possible 1968 NHRA 427 SOHC entry for SS/A racing.

Came across this cool article from June 2012:

https://www.motortrend.com/how-to/mdmp- ... he-mighty/

"Weighing in at a hefty 680 pounds, the new engine served notice that the competition had something to fear when dynamometer numbers revealed that the single four-barrel version produced 616 hp at 7,000 rpm and 515 lb-ft of torque at 3,800 rpm. And as if it couldn't get any better, the addition of the dual four-barrel carburetors stepped the horsepower up to 657 at 7,500, and torque numbers jumped to a stump-pulling 575 lb-ft at 4,200 rpm. "

Do those specs seem high?
Especially the 60 ftlb Torq gain just by adding dual quads?

Somehow I have down 4v=575hp and 8v=616hp which jives a lot better in the Gonkulator (for a nominal  factory rating with iron manifolds) vs eg Jay's SOHC dyno tests.
Anybody have any other specs & sources on SOHC Torq & HP?

cam 280-288  lift 621-624 250/254 @50  lobe 112
hooker super comp 1 3/4
I wasnt carrying the exhaust on my 11.07 pass.
compression 10.75.

Just a heads up Werby Im gonna have a new set up this year.
Maybe not much,,Different cam alittle head work probably enough to get me into the 10s.
I mean I only need .07 Im sure Im gonna get that. May have gotten it with alittle cooler weather.

Thanks LOL I forgot I'd started Gonkulating this about a year ago in this thread! Cant find it all tho so not sure what I guessed at.

Gonkulator says the MR intake is adding about 23 Torq & 30 HP vs the LR intake.
About .15 ET and 2 MPH better than the LR.
That's if weather, driving, track & tune are all the same.
Gotta be knocking on the door of the 10s already.

What about more converter? Torq peak is 4000-4200 in the Gonkulator so near 4000 stall might be ideal, especially if you add more cam.
Then again, not as streetable.
Admirable goal to have a street car in the 10s just by ditching the exhaust!

https://www.youtube.com/watch?v=_PVXvHkr-Vs

2.5" is down 20hp/20ftlb along the curve compared to 3.0" on a 600hp combo, would think a 700hp setup would be hurting it more. 

Maybe just me, but to reach 700hp would seem to mean optimizing heads (ported vs cast), compression, cam duration/lift...right to a high level.  Then seems odd to go back and de-optimize the motor with small exhaust when there absolutely is an alternative with minimal drawback beyond being tougher to fit (but possible). 

Now, if this was a street/strip combo where the exhaust is getting dropped at the track, that's a different scenario but I read this as street only.

Great video, especially the sarcasm about the old "an engine needs backpressure" urban legend.

Incredible though, to me, that all that 2.5" pipe ONLY killed off 21hp out of 622hp (if it was jetted rich enough with open headers to begin with).
That's only a 3.4% power loss.
So only a tenth or so ET and maybe 1.5mph assuming that Rat was in a Camaro/Nova.

Seems that good old Glass Packs  / Cherry Bombs from the 1960s-70s are still very hard to beat, if they're done right:
* Same pipe diameter as the exhaust pipe - no narrowing down
* Perforated, not louvered. Louvers are for fastback rear windows.
* Big case with lots of glass to cancel noise & waves.