I have a 1968 Firebird with a 350 2 barrel and 2 speed trans. What is best way to get a little more pep out of this car?

A four barrel set up?
New gears in the rear?

I would rather not take the engine apart, or change the trans.

Electronic ignition with super coil is a good economical start. Try that and see how you like it.
Jim

Believe me I'm no expert, so forgive the question...But will changing the spark make a difference?

Yeah, that's why I suggested it. Got to start somewhere and I believe in doing it one thing at a time. Not very expensive and it's not real time consuming. If you decide to get even more peppy the electronic will work better with each other upgrade you make.
Jim

Sounds like a mild combination. The engine/tranmission has to work as a system, so you need to match the parts. To assist the 2-speed gearing (with a stock long block 350) you should focus on improving mid-range torque.

Air in:
Four barrel manifold and small four barrel carburetor (450-600 cfm squarebore or maximum 650 cfm spreadbore). Don't waste your time with adapting a 4bbl carb to a 2bbl manifold or vise-versa. Edelbrock Performer intakes can easliy be found used. Pick a carburetor brand that you are most comfortable with tuning. Make sure the secondaries are vacuum actuated, not a mechanical linkage.

Air out:
Dual exhuast will help even with stock manifolds. No more than 2.25" is necessary with this mild combination. An H-pipe or X-over pipe will assist in torque. If you go headers, use the smaller primaries (1 5/8"). Ram Air manifolds would be great for this combination.

Optimize ignition timing:
Try advancing your distributor in 2 degree increments. Keep doing this while listening for detonation during acceleration. When you start to hear detonation or performance drops off, retard it to the last ping-free setting. Using electronic conversion kits will reduce variation from points wear. Crane sells a unit with a rev limiter for less than $100. Good insurance for stopping disaster.

Final note, changing the gearing will improve off the line performance, but fuel economy will get worse and the higher revs on the highway will be both annoying and increase engine wear.

Swapping the trans might be something you didn't want to consider, but it would make a big difference. Since you have a mild engine, you could probably get away with a stock rebuilt 2004-r. You'll have a better off-line acceleration gear as well as an additional economy gear. Any more mods and you'll need to have a 2004-r specially built.

Changing the plugs is critical, too. I'm running Bosch Platinums and they run much cleaner than AC or AC Rapidfire.

Also make sure the exhaust manifold heat riser valve either works freely or is wired open.

The two barrel carb flows more fuel than a four barrel until you mash the pedal. If most of your driving is around town, the two barrel is a good carb. It won't cut it for drag racing. One of my best sleeper cars was a '71 Impala with a 400 2 bbl that was very fast off the line.

Just a quick comment since gas milage was mentioned. I have never had a car with worse gas milage! I can almost see the gauge move at highway speeds, always assumed it was the two speed trans.

Where is the heat riser valve??? Got a pic?

I don't think changing the transmission to a TH350 will affect gas mileage that much. The final drive ratio on both is 1:1. Unless you swap in an overdrive unit I would think the mileage would be a wash. The 350 should have more performance off the line. It having a lower first gear.

To expand on Vikki's comments, a lot of people over-carb when switching to a 4bbl. Then they lose low-end reponse. Stay conservative with the 4bbl size and you'll be very happy.

The deeper gear of the 2004-R will improve economy because you won't need your foot in it as much to get off the line (normal driving) and on the highway your revs drop significantly. Better off the line acceleration and fuel economy? Might want to reconsider your resistence to swapping trans.

Are the Electronic ignition upgrade kits any good?

I've had good success with the Pertronix Ignitor II, but it is not as complete and comprehensive a solution as HEI or Mallory Unilite and requires careful attention to ensure the wires are not going to go into the weights.

Your fuel economy issue, not mentioned in your first post, could be caused by something as basic as a dirty or poorly performing carburetor, rather than an undersized carb.

Also check your mechanical and vacuum advance in your distributor, another way to waste a lot of gas if they aren't working right.

The manifold heat riser is a weighted flapper in one exhaust manifold. It is supposed to open when the bimetal spring absorbs enough heat, to allow free flow of exhaust gasses. If the spring breaks or the valve sticks in a closed or partially closed position, you will get low power and poor economy. Short of surgical removal of the balky part, you can wire it or weld it in the open position.