273 for early A

As to the Js, at ~72cc, the total chamber size adds up to; 2cc in the decks+5cc in the eyes+6.8 with an .028 gasket required to get .038Q, totals 13.8 so far, and the heads adds to~85.8, which drops your Scr back into the basement at 8.68, so yes they will soften your hit extremely. To run that 58/59 ICA with authority, your Scr will need to be ~9.6@800ft elevation. This will require a TCV of 659/8.6=76.6cc. Subtracting 13.8, leaves 62.8 for the heads. That's a lot of cutting on those Js, which will require more cutting to properly fit the intake.
I think there are no iron heads close to 62.8 , except perhaps the Magnums which I think come in at ~58cc. Those are just too small to work with and still use the 58/59* Ica..
For example;
By swapping in the .039 gasket for a new Q of ~.049 you're still in the ballpark, and that will get you another 2cc; so total now 15.8. Add 58=73.8 ..And your Scr with that would be 9.93, which is predicted to make 165psi, .... at 800ft elevation
But if you are operating at lower than 800ft, then it ain't gonna work. Most guys will say that 165psi is already borderline too much for 91 pump gas
So for example, with the Scr of 9.93 but now at 300ft, your pressure rises to 168psi, and you can't drive that at WOT, no pumpgas will support it..
So whaddya do?
You put a bigger cam in it is what. It's the cheapest solution.
So say with a 64* Ica, the Magnum combo comes in at 160psi@300ft elevation; Badaboom!
So what's a cam look like with a 64* Ica? Well it could be a lotta things but here's a theoretical one ;
276/276/116/112/108 LSA/60 overlap in at 106
That will be a ripper in a teener. With a bottom end still about as strong as the stocker.
Now if you make that a solid-lifter cam, your net after lash could be as much as 238*@.050. That would be a heckuva ripper.
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But in all honesty, I don't think that is what you want.
So lets back up and see what can be done with the Js and a smaller cam, cuz I want to drive home the solid lifter cam option.
So lets go back to the 13.8 basic plus shave the heads to 68cc for a total chamber volume of 81.8cc, and therefore an Scr of (659+81.8)/81.8=9.06 So..... what can we do with that? Well at 300ft elevation now, with an Ica of 52*, you can make a lower rpm torque monster, perfect for 3.55s and a modest stall TC. These 52* will get you~160psi, and no torque loss compared to the stocker, yet plenty of power for a DD.
What's that cam look like? Well you build a dozen cams around that number, or more but here's a theoretical one;
248/256/128/116/112LSA/28overlap, in at 110. there you go, that's the stock teener cam. But But you say where is the power coming from? Well if I recall this cam peaks around 4800, maybe a lil sooner with the Js.
But the neat thing is this;65mph in 1.45 second gear with 3.55s will get you about 4440rpm, right on the fat part of the power curve. And so, you will be going thru the power peak, or near to it,TWICE on the way to 65. That maximizes your average power on the trip. But lets look at what happens at 30 mph when you stomp on it. This will be ~3500 rpm in low gear, on the fat part of the torque curve now, and first gear will go to 45mph@5200 with those Js.

But say you deck the block to pop the pistons out .005, and use the .028 gasket. You got no Q to speak of with the Js,so this will be fine. .005pop-up is -1cc and the .028s are ~6.8cc and the eyes are still 5cc and 68cc for the head, the new total is 78.8.... and the new Scr is 9.36, and Ta-da the new Ica is 56*. Yeah a bigger cam with a higher operating rpm. Is that a good thing? Maybe, and maybe not... cuz with the smaller one we were trapping 65=4440 very close to the power peak. But now the power peak is moving up ~250rpm to 5050. ..... so what's gonna happen at 4440? Well my guess is the car will not be any faster to 65mph with the bigger cam. But if you want one here is what it might look like
256/262/124/117/110LSA/39overlap in at 108. Hey that looks pretty nice.It will be faster to redline in second ~90mph, but I doubt you would see much difference in the zero to 60.
But hang on a sec, what if we went to a different piston without the stinking 5cc eyes which at this power level you don't need. That's 5 big beautiful ccs. How much did we cut off the Js? Hyup 4cc. Hey this is getting exciting. Ok so lets not deck the block and not mill the heads, and say the pistons come in at .011 in the holes. Ok, I get 2.2cc in the decks, 0 in the eyes, 6.8 in the .028s and back to 72 on the heads, for a TCV of 81cc... and an Scr of 9.14, and with the 256/262/110 cam I see 155psi, good for cheapest gas. A lil down on power on account of 155psi versus the 160 that I have been targeting, but what's not to like about burning 87.
So lets go see in your stash if you have a cam suitable to be installed with an ICA of 56*.
Well no, I don't see it. But remember that Whiplash? She goes in at 55* by the spec........... lol; kidding!
Lots of companies can supply you a 256/262/110 cam; it is a common size.
But here comes the punchline..
The 256 advertised could again be at .008,.006, or even .004 Tappet lift. Do we care? yes we do cuz it affects the idle, and low-speed operation. But more importantly, it plays a big roll in figuring the .050 durations which to you is really really important. So for now lets assume all the calcs I have been doing were with .008 tappet lift cams.
So what .050 will this 256 cam give us?
Well with a hydraulic FT cam this might be from ~216 to as little as 204, so you gotta pay attention cuz those 12*degrees could represent 25hp at this level. But typically you might get a [email protected]
What about a solid? Well that's really tricky, cuz if you order a 256 you can't expect it to be a 256 in your engine, cuz the lashing always takes away some duration. So you gotta start with a bigger cam, lash it, and see what you end up with, hopefully a 256*,lol. So say you ordered the next bigger solid lifter cam which might be a 262/270/110 which after lashing just theoretically* happens to be exactly 256/262/110 so we can compare apples to apples.
Now, this SFT you might be able to get it with 38* ramps and end up with 218* intake degrees. Wow! That is one size bigger than the HFT which was 210* ...
So what you end up with is zero loss in low-rpm torque, an increase in midrange,and perhaps*15 extra horsepower at peak. Oh, and we are still burning skunk-pee 87 @155psi.

EDITs in italics*