I have the original 327/275 motor with 128,000 miles, the previous owner said it has never been rebuilt. It currently leaks oil from the front and rear seals and could use some help in the power department. I would like to rebuild the motor but I am not sure how to do it right to keep it original, I would like to up the HP to at least 350 which I think would be Vette specs? I want it to appear original. When restoring a motor do you replace all of the guts with new components? What is the least I should bore in the interest of longevity .10? It still has the original smog pump(not hooked up)should I leave it on? To build it to vette specs can I use the same intake and camel hump heads and just up the compression to 11-1?

When you build a motor you need to replace bearings,rings,oil pump,pistons if you bore,recondition the rods,new cam bearings,freeze plugs,hot tank the block.As far as least boring specs it is determined by the wear in the cylinders .040 is very streetable.IMO you should lose the smog pump.As far as the intake is concerned there are many options a good dual plane aluminum would work great.Camel back heads are a little out dated, the seats cant stand the unleaded gas. you can buy a good set of iron heads for what it would cost to make double humps last with todays gas.Also if you have 11 to 1 compression you'll have to go to your local airport to fill up,the engine will ping even on high octane.10 to 1 is borderline for the street.You didn't metion camshaft you wiil defenatly have to change the cam,lifters,valve springs.Comp cams has cams that are matched to factory muscle car specs,and you can get the whole kit,cam,springs lifters timing chain.

This discussion might help you.
http://www.camaros.net/cgi-bin/forum/ultimatebb.cgi/topic/4/9571.html?