I have a 72 Lemans convertible with a 350 2 bbl auto with about 75K on the car. Have to go into the engine as every seal is leaking.
Any suggestions on changes that will improve fuel economy or driveability? It is a 49 state vehicle. Not looking to do a major overhaul, but thinking camshaft, carbs, electronic ignition, emission stuff that can be disabled, etc.
Any stuff that I should do while I have the engine out?
Hmmmm, every seal is leaking and you are going to have to totally disassemble the engine, yet not rebuild it. Hmmmm, not making sense to me. Have you done a compression test to see if the engine is low on compression and will need rings?
If you just reseal it, I assume not including the head gaskets and you are leaving the heads in place. Is the rear main seal leaking?
If you pull the engine, you might want to take the car to a muffler shop and let then heat up and loosen your exhaust pipes to make it easier for you. If you don't already have dual exhaust, you want to add this to aid in engine performance and can add a little gas mileage.
When you replace the pan gasket, clean out the pan and install a new oil pump/screen - that's a no brainer. Install a new aftermarket hardened steel oil pump drive to go with it.
With engine out, replace all freeze plugs on the block.
1972 350 2 bbl is rated at 175HP and 8.0 compression. You can go with a Competition Cams grind having 110 LSA to boost cylinder pressure, but in doing that, if your rings are worn, you could wind up with excess blow-by or burn oil. Get matching springs to go with the cam but keep lift under about .450". Install new valve seals, but if the valve guides are worn, the higher lift/heavier springs may accelerate it more and you will be burning oil.
Install a new timing chain & gears.
Swap out to a 1972 factory Q-jet intake with Q-jet carb. This will help with fuel mileage running on the smaller primaries and give you an extra kick with the larger secondaries. You don't get fuel mileage from these older cars as you do the newer cars. If you can get 18 on the highway at steady speeds and flat roads, you will be doing good. Open element air cleaners can help a little with this and then dialing in your timing can maximize gas mileage. If an automatic trans, an RV converter with less stall can improve gas mileage as does a shift improver kit to give you fast/crisp shifts of the gears.
Electronic ignition is a personal preference. Points work fine, but todays Chinese stuff can be a problem. I have used the Pertronix conversion for points and had no issues. You can use a factory or after market HEI which many like. Then there are complete aftermarket plug-and-play electronic small cap distributors.
Don't know what emissions crap you have on the engine, so can't help you on that.
So that is for starters.