The quick answer is that cam needs more compression,a lot more.
But it's in there now so your best solution is a hi-stall TC, say about a 3200. Unless you have 3.55 gears or better, then a 2800 at the very minimum.
Here's the long version
>First the teener with the stock spec 240/248/112 cam
Static compression ratio of 8:1.
Effective stroke is 2.82 inches.
Your dynamic compression ratio is 6.95:1 .
Your dynamic cranking pressure is 132.97 PSI.
V/P (Volume to Pressure Index) is 108..............................................
108VP
And then the stock teener with the factory 268/276/114 cam
Static compression ratio of 8:1.
Effective stroke is 2.57 inches.
Your dynamic compression ratio is 6.43:1 .
Your dynamic cranking pressure is 119.91 PSI.
V/P (Volume to Pressure Index) is 89....................................................
89VP
Notice the VP numbers. These indicate or help us to understand why the lack of compression turned your teener into a dog. Notice how your engine has no only 89/108=82% of it's former stunning performance. That means the bottom end has lost 18% . You can think of this as having directly lost 18% of its former torque. Or you can think of it like going down to 82% in the rear gear ratio, say from 2.76 to 2.26; yeah that's doggy all right. Or from 3.55 to 2.91s
Notice also that your cranking compression is down to 90% of it's former number, and notice that your Dcr has fallen to 92.5% of it's former already very low number.
The proper solution to this is to pump up the static compression ratio. With iron heads and open chambers,(no quench to speak of) You can bump it up until the Dcr hits about 8.0:1
So crunching the numbers, I get
Static compression ratio of 10:1.
Effective stroke is 2.57 inches.
Your dynamic compression ratio is 7.98:1 .
Your dynamic cranking pressure is 159.36 PSI.
V/P (Volume to Pressure Index) is 119............................................
119VP
See now yer talking! The factory teener came in at 108VP, and with an .030 overebore and with the above specs, you have now gained VP to the tune of 119/108=plus10.2% And a whopping 119/89=plus 33.7% more than your current set-up.
If you put some closed chamber Magnums on there, you'll lose 9cc of total chamber volume, but when you swap out that .020 steel factory head gasket, for an .028 , you'll gain back about 2.4 for a net loss of 6.6cc, and your Scr will jump from 8.0 to about 8.5, so it still sucks. So that by itself is not a viable solution.
No, the proper solution is to get the pistons up to the top of the deck AND get you some Magnum heads. Then you are approaching 10/1 and getting the Quench the engine needs and you can boost the Dcr up a lil more, say to 8.2
And that will look like this
Static compression ratio of 10.3:1.
Effective stroke is 2.57 inches.
Your dynamic compression ratio is 8.21:1 .
Your dynamic cranking pressure is 165.35 PSI.
V/P (Volume to Pressure Index) is 124..............................................
124VP
And
that will then be a total boost from the factory teener of 124/108=plus 14.8%, and a boost from the current combo of 124/89=plus 39%
This is at the Dcr limit for pumpgas and tight Q of .035 to .045 or thereabouts, so it can't get any better than this.
Hey, I made this mistake once too, so I know exactly what you're going thru. There is no tuning this away.
So the answer is; hi-stall or compression. Or for a real boost,both!
To run 8 to 8.2 Dcr with iron heads is gonna cost you premium gas most of the time. With open chamber heads, better make it all the time until you get a good tune into it.
Of course the cheapest answer is to pull that 268cam outta there,lol.
And if you don't boost up the compression, this combo will suck gas big time, but you have probably already discovered that,lol.And there is a threefold reason for that. With the cam in at 110, there are only 104* of power extraction, compared to the factory's 120* when in at 108*. And the second more important reason is the lack of heat in the combustion chamber. With the current combo's 120 psi of cylinder pressure, engine efficiency is way down; she is just not making any heat at cruise rpm. And the third part is; because of the low efficiency, you will have to use more throttle than normal to achieve your cruise rpm.
And if you plug in a 3200TC well forget about measuring fuel-mileage.
And now for a real eye-opener
Static compression ratio of 9.25:1.
Effective stroke is 2.82 inches.
Your dynamic compression ratio is 8.02:1 .
Your dynamic cranking pressure is 160.40 PSI.
V/P (Volume to Pressure Index) is 132...............................................
132VP
Here is your factory teener with the 240/112 cam and the Scr boosted up to where the factory shouldda put it. Now that's a tire-fryer! And she's something you will be able to drive for hours and hours and hours on a single tank of gas.
If you put 4.30s behind this and a 2800, you can hit about 60 mph at the top of second gear, and be about the quickest thing around, to 60.
But more likely you'll like this with 3.23s, as a nice cruiser. 132/108 =plus 22% over stock, bottom end, which tapers off as the Rs rise,and so the advantage diminishes as the Rs climb to about peak-torque or somewhere around 3200/30mph in first for this combo.
And just for comparison, heres what a factory 360 looks like
Static compression ratio of 8.0:1.
Effective stroke is 3.02 inches.
Your dynamic compression ratio is 6.91:1 .
Your dynamic cranking pressure is 131.95 PSI.
V/P (Volume to Pressure Index) is 120..................................................
120VP
And one more; If you advanced this cam with a 106* install, it could look like this
Static compression ratio of 8.0:1.
Effective stroke is 2.66 inches.
Your dynamic compression ratio is 6.62:1 .
Your dynamic cranking pressure is 124.66 PSI.
V/P (Volume to Pressure Index) is 96........................................................96VP
Better than a poke in the eye but still way down from the factory teener, and now sux gas even worse.
Read about VP here
Cam Timing vs. Compression Analysis
And here's a 1969 225cid with the factory 236/240 cam
Static compression ratio of 8.4:1.
Effective stroke is 3.58 inches.
Your dynamic compression ratio is 7.42:1 .
Your dynamic cranking pressure is 144.92 PSI.
V/P (Volume to Pressure Index) is 85.....................................................85
So your current 89VP is just 89/85=plus 4.7% stronger than good-running 225 from 1969. BTW; you should be able to run 87 gas in that current engine. lol.