AJ/FormS said

You do realize that Until the secondaries open, your new top end will not make a hill of beans difference right? So if she can't spin the tires now, both of them,then the new set up won't be but a tad quicker to 30/40 mph, depending on your current rear gears and TC stall.While the duals and freeflow exhaust will help some below 3500rpm(maybe lots depending on how restrictive your current single? pipe is; the secondaries may not open until 3000plus rpm.With 2.76s, that would be about 35mph.See what I'm getting at?
-If you put a bigger cam in it, all other things remaining, it may actually be slower to 35mph.This is because without a compression increase to keep the Dcr up, a bigger cam invariably trades away low rpm torque for high rpm power.
If you really need some giddy-up, the biggest bang for the buck will be a slightly higher stall TC. Then gears if you can afford to give up some hiway comfort; and you can never lose with a free-flowing exhaust.
-Since you already said gears, then that is the very first thing to do;before you spend a bunch of money on the engine. By itself a 20% increase in gearage will be dynomite, and absolutely none of your planned mods will make it any quicker below 25/30mph or so,than it now is, and it will not be felt until the car is really moving, and then you will be speeding;cuz 5400 with 2.76s in first gear is about 65 mph.
I'm not trying to ruin your day, but gears should be #1 for you;not last.
-Going from 2.73s to 3.55s is a 3.55/2.76 =plus 28.6%. This is huge. Your engine will feel like it grew by that same 28.6% or over 100 cubes. No other mod to a NA streeter will touch this mod for grin-factor.
-BTW, with a stock compression ratio, I would leave the cam swap for dead last. I mean it.It's really hard to beat that stocker for off-the-line giddy-up.And if after the gears are in, and the exhaust is hung, you still feel the need for more, a 4bbl set-up might kick in another 15 hp; but you might not feel it, until she gets wound up. You'll hear it,all right, but it will be awhile before it gets going.Worse if you stick that 268cam in there.
-I suppose I'd be remiss if I didn't take budget into account.If you already have the money earmarked for your plan, there's not much wrong with your plan, just so long as you have money to finish the combo.
-But if the cam is for sure going in, then at least cut the heads to get back some Dcr.
Whatever you decide;All the best to you

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M_Body_Coupe said

Here are some DIY porting results on a set of 596 castings. This was about a 3rd set of heads I ported, pleased with the results. Your are probably not going to go that extreme in terns of the port work though.

LIFT I E

0.100 67 57
0.150 99 79
0.200 130 104
0.250 162 125
0.300 189 140
0.350 215 152
0.400 235 160
0.450 253 167
0.500 262 172
0.550 261 175
0.600 248 177

The finished chambers/ports looked as follows:



I would assess the situation from the perspective of how much $$$ are you going to sink into either stock casting to make it perform? These days, that type of money will buy you a decent aftermarket iron head.

At the very least, consider optimizing your static CR to work with the heads and camshaft in particular. That will be the key to making good torque.

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