ive got a 1990 RS with L03 with 90,000 miles, i need more power, ive already got the hooker shortys backing up to magnaflow catback, 3.73 rear with posi traction. OPen element. what would be my next mod, if i was to swap out the intake manifold, would i get any gains from that, and if so how much, and is it worth it. Also what about putting a shift kit, and a corvette servo in the 700 r4. which way should i go. im thinking of just buying a brand new crate L31 350, but dont have the money to do everything right now.

anybody got any ideas??

Intake manifold won't make much difference at your power level. If you have any plans to upgrade engines in the future (sounds like you do) then I would put off buying a manifold. You'd need a different one for Vortec heads anyways. Buy parts that will fit on both motors, i.e. the headers and exhaust you have.

Pick up some subframe connectors and maybe a wonder bar, makes the car "feel" a lot better.

It seems to me that the cam and heads flow match the intake manifold on stock TBI. I was going to do what you are thinking about. Manifold swap. little here, little there. Then I just got crazy and created a beast. 383 vortec, bored out TB, 454ss injectors, walbro 255lph fuel pump. Once you stop, its hard to stop. I would either upgrade your current engine, or save up and do it all at once with the l31. You can buy parts that fit both engines, but you may find that you end up with 2 cams, 4 injectors, 2 throttlebodies....etc. because the first one was "big" enough to run the 305 and "not big enough" for that L31. Plan it out and stick with the plan. It will save you money. I am not saying go all out...but if you are thinking of swapping anyway, build that L31 on a stand and drop it in. instead of robbing Peter to pay Paul. It just sucks to have 2 engines on stands taking out a cam to put in another. Been there. Done that. Just my 2 cents. Just Plan it well.

I would have to agree with the previous posters. I was in a similar situation as you and definitely wasted money on parts I could not reuse (intake manifold, cam, etc). You're aready off to a good start with the exhaust, since it'll work with your future plans. If you're not looking to dive into the vortec motor yet, put your funds toward other areas of the vehicle that will benefit regardless of which motor you go with (like subframe connectors, wonderbar, suspension, etc).