Checking Intake Manifold Fit After Resurfacing Heads

Might it not be cheaper, easier, better, to just change the cam's ICA to adjust the Dcr?
By the time you add up all the machining costs, the port-matching, new pushrods, possible adjustments to the eyebrows, and possible changes to header clearances ....... I mean 4ccs cannot be compensated for by retarding the cam, but a different cam, or a custom cam, or a different type of cam...... might. As would different pistons with a larger cd.
>I say this because I have not had the greatest luck with multiple machinings. I swore I'd get the proper pistons next time, and not machine anything, beyond what HAD to be done.
>As to the pushrod length, in all fairness a hydraulic lifter should be able to compensate for a .020 cut..... BUT Should it have too? If you have adjustable arms , then,maybe no problem. But what will that do to your geometry? And then there is the small matter of lifter pump up. The plunger has about .090 or even .100 inch of compensation but when/if pump-up occurs, pow, those valves are into the pistons ....... unless you have built in an overly generous safety clearance. Nobody does that because that causes a compression loss that you just worked hard to overcome. Typically guys run about .020 lifter preload or a bit more, cuz that is probably a little less than the valve to piston clearance. So then if you overspeed the engine and the lifters pump up, then nothing ..... hopefully.... touches. So pushrods always get measured, ordered, and installed, last.
>But again, delaying the ICA has the unloved side effect of reducing your low-rpm performance. Here is a 340 similar to yours.
With a 10/1 Scr and an ICA of 62* ( a cam of 268/276/110 in at 108.) The Dcr comes in at 8.09 and 162psi with a VP of 130. The pressure shows that this is about the max for pumpgas. If this is your target, it requires a total chamber volume of 77.37 at stock bore and stroke. But if you had 4cc more, or 81.37 total chamber volume, then the numbers would come in at 9.56Scr/7.74Dcr/153psi@123VP. Notice the loss of VP. To get the low-rpm performance back without changing the compression, the ICa would have to be reduced to 56*. The numbers then come in at 9.56Scr/8.08Dcr/162psi@137VP. Notice that the Dcr is back up, as is the pressure. But look at the VP; it has jumped 7 points from the original 130 .... even at the Scr loss.
So that's kindof cool.
But wait-up. If these are both hydros,and from the same manufacturer, then the second cam is one size smaller at .050, so that might be 15 or 20 hp loss at the top. ... But if the first was a hydro, with typical 46* ramps, then the .050 of that cam would be 222*. and if the second was a fastrate SOLID with a 222@050; it might have ramps of 40*, and so it would be a 262 advertised. This could be cut on a 108LSA to yield a 262/268/108 and in at 108 would yield a 59* ICA, which after lashing might be 56*, exactly what is needed.This cam is practically identical to the first now, except it makes more torque, better fuel economy, but with quite a bit less overlap;perhaps as much a 8* less, will likely make a lil less power.
So this second cam is a pretty good deal, if you don't mind the occasional lash adjustment......... And no machining was required.
BTW his is just an exercise in what-ifs. The best solution, IMO, is reverse-dome pistons.And that would give you a little more flexibility in cam selection