Is a carb spacer on a stock 350 going to help?  

If you are talking about a spacer under carb, it might help a little but it will not be magic and if you are looking for MPG gains from it, look elsewhere.  

Just looking for better performance/low end torque.  MPG would be nice but not really expecting much out of the pickup.  

If you are looking for a meaningful gain, forget the spacer and change intake manifold as stock one does not flow very well or very even.  

i like the Edelbrock Performer intake on a chevy sb. it's a big step up over stock as far as throttle response, low end through midrange torque. and they run like around $125-130-ish.  

So do I just put on the new intake?  Is there anything else I would have to do when putting it on?  What I am trying to ask is,  Can I just put on the intake and leave everything else alone for now?  

Yes you can as intake alone will make a very noticeable difference. Engines of that era had crappy intakes and today new motors run so well because among other things they have much better tuned intakes too.  

an stick to the dual plane perfomer series not the rpm or stealth... unless you match it with a cam/compression and gears.

if you have a spread bore carb get a manifold to fit it, same goes for a square bore, otherwise you'll wind up with a spacer to adapt em.  

Years ago I used to use Elderbrock Street Masters with very good results but I do not think they make that one anymore.  

I never had the street master, I'm pretty sure it's what they call the performer now...  

The old Streetmaster had basically straight runners to ports and just before head port they had ridges on side of runner as it turned to square up with port that was supposed to create a little turbulence to help mix fuel and air. The runner diameter was smaller than Torkers of the era. It was really strong in mid range and was not mushy off idle  

Thx!  

There is a a couple of newer style StreetMasters on Ebay right now pretty reasonably priced too.