How to determine need for rebuild

[AmadeusCharger500]

I picked up a 74 Satellite last year and I am just about done with body work, so the engine and trans are out.
It is a 318 with 904 trans, single exhaust. Every trick known to man for emissions on the thing. I assume it is 2.72 gears in the back.

The selller claimed car had 38,000 original miles and by the looks of the break pedal, perfect headliner and such I tend to think this is true.
However while the engine is out I would like to take care of some things.

I would like to do a mild rebuild but don't know if I should just go all the way. I think it may need rings due to black smoke occasional from tailpipe. Other than that I just don't know what a 38k engine should need or not.

I would like to improve performance but would also like keep decent gas mileage.

What measurements should I start with?
Should I get rid of the single exhaust and manifolds?
What emissions items to keep and what do get rid of (Some of them are just weird to me).
Head work is a definite I would guess but I am sure I need some measurement there.

Many more questions to come.

[Chryco Psycho]

Dual exhaust will help for sure
black smoke has nothing to do with rings , probably the choke is sticking closed or just running too rich
I would replace all the gaskets & frost plugs , the short block should be fine , rings could be swapped out but you need to hone the cylinders to seat them back in
the only emiisins needed are the PCV virtually anything else can be removed

[RogerDodger]

Also I would change the valve stem seals and maybe the timing chain as long as your changing all the gaskets.

[AmadeusCharger500]

So most of that stuff running to the carb can be disconnected. It has a 2 barrel on now.
Anyone know how many MPG this thing should be getting now and how much it would change if I did some performance upgrades?
I would assume the emissions items were not helping gas mileage?

[fast360]

You would want to keep you dist. vacuum advance and brake booster hooked up still, along with a PVC. i don't know what a 318
does on gas stock but with those gears it would be fairly good 16-18 mpg? maybe more I'm not sure. if you keep your cam
and carb modest and your foot out of the pedal and it will be good. gears don't help with milage if you plan on sticking with
the gears you have to be modest with cam and carb a 600 with a performer intake and a little cam would be good i think a stock 340 cam would be good but with exhaust. im not sure with the cam and the gears im not a fan of anthing lower an 3.23

[AmadeusCharger500]

I've decided to take it to a machine shop. Have the cylinders honed so I can put new rings on.
Should I have them do anything else?
Hone, polish crank, wash.

Would there be any benefit to changing the cam, or heads?
Or should I just get a valve job.

The heads on it are numbered 0384  284367(3) Not sure about this last number.

Should I get a determination of what compression I am running now, and what is optimal?

[Purple440]

It depends on what you want to do with it.  The experts (that does NOT include me) around here will need to know how your going to drive it so they can recommend stuff.  Since your tearing it down anyway you might as well have the block and heads cleaned up if they're not already from the last rebuild, check for problems, ect.  Valve job, cam, intake and carb upgrades, balancing...that's what I'd do, and keep it small if your keeping your exhaust system IMO (go dual).  I'm guessing the 318 2bbl compression was in the 7's??  Upping that a point or two would increase power obviously, and the gas millage, so I've read.  But then your talking higher octane fuel, maybe, and probably new pistons.   

I used to have a 318 2bbl when I was in college and the cam looked like a broomstick.  I put on a new eddy 650cfm carb and performer intake thinking it would make a difference and not having a clue...of course it didn't, at least not that I could tell.  Top end was still 90mph     Had dual exhaust too.

G/L

[Steve P.]

For sure clean the block and heads. Have the machinist check the block and heads. Too much taper in the cylinders will be sending you to the parts catalog. New bearings, freeze plugs, rings, gaskets, seals, cam, timing set, valve job. Check everything for straight and parallel.

Before it's totally pulled apart the machinist can measure and tell you where you should be compression wise.

You really have to know what you want out of the motor before putting a plan together for the rebuild. Normally more power means less mileage.