engine swap....how tough?

I recently purchased a '90 Formula with a 305 TBI, just under 130,000 miles. When I bought it, the engine fired right up, no hesitation, and didn't smoke.....well, lo' and behold 2 weeks later, it is having difficulty staying at idle when first started, and it's smoking...I believe it's burning oil.
Now, this was a "budget buy" in the first place, and I don't have a whole lot of money to spend on this car, but it does have to be reliable. So my question is, how tough is a motor swap? I have never done it before, but I do have a buddy (older guy I used to work for) who would supervise (he's done this work plenty of times before). So it would be me, with no experience, some tools, a "how-to" book, and a little supervision.
On a side note, i'm in the military, so I have very minimal mechanical experience, but hope to be starting school soon to be a mechanic when my enlistment is up. So I have a high interest in doing this, but my question is how difficult is it and would you recommend I attempt this?
And the swap would probably be to a 350 TPI or an LT1...cuz the LS1 is too expensive

A straight swap from the 305 long block to a 350 longblock with the later model heads and re-using your current fuel system is a weekend job easily.

Once you start swapping TPI for TBI, or going with the LT1 and dealing with opti spark things get a little more complicated.

You could swap a good L98 long block in with your current set-up and then do the TPI or whatever other fuel system upgrade after you get the actual bottem end and heads swapped in and running. That way you know you have a good bottem end to work with.

I would love to go with the L98, you think that is a good idea? Easier than an LT1 swap? I'm not real interested in high HP numbers, although it would be nice, I need reliability.

Im confused, Your sig says you have that SS, why are you messing with this 3rd gen. Your newer one is bound to be more reliable??

Ah yes, maybe I should clear that up. My SS is in storage...and is going to be in storage for probably 2 years. Full-coverage insurance is killing me, so I have the SS on comprehensive only (can't drive it) and liability on the Firebird. If worst comes to worst, I can fully insure the SS again, but I am doing this to save money until my driving record "calms down" and I can drive it again....I just CAN'T sell it

Putting your TBI on top of a L98 long block works pretty well. A guy on thirdgen.org is running 14.7 with a stock tbi and L98. Its straight forward, pulling the engine is probably a 3-4 day process for someone who's never done it, then putting the new one is is probably 3-4 days, so allocate about a week or two to get it all done. If you're sticking with a stock L98 350 and tbi get a 350 Caprice chip and you'd be doin fine. A 350 knock sensor is also needed, but all the other sensors will be a-ok.