Tlowe has some good info on a "Spec" engine, he can tell you how much power it should make. What compression to run per camshaft used.
Mike Kirby, can set you up with what ever you want.
http://www.sissellautomotive.com/Mike Barile
http://www.ebay.com/itm/194-230-250-292-...0f1a774&vxp=mtr has parts, cyl heads etc for your inline needs.
Depending on how tall your rear tires are will let us get an idea of your final drive should be.
Head work is where most of all your power is going to come from.
If you want a lot of power from your six, the cyl head work is where you do not want to skimp on.
Lumps, bigger valves, performance valve job all play an important roll.
You need to bump up the compression a bit if you are going to run a bigger camshaft.
Go w/a minimum overbore on the pistons, it's not like it's going to be a day & night difference betwwen a .030" overbore to a .060" overbore.
Now a 4" inch bore, now you talking, but, that is not recommended.
I always wanted to run a 3.75" stroke. Need a custom crank & that will cost a lot.
You can turn down a 292 crank, but that's a lot of work.
strokersix
https://www.inliners.org/ubbthreads/ubbthreads.php?ubb=showprofile&User=4995 did this recently.
If you want a torquey engine & can fit a 292 into your engine compartment, that would be a better choice & can make more power up to a point, depends on how much you want to spend & how fast you want to spin the engine.
You can do the oiling mods, buy Leos book & learn a lot.
http://www.amazon.com/Chevrolet-Inline-S...=inline+6+powerYour engine is already gear drive.
And I'll get the jump on efi diy, you can always install a 4.2 trailblazer inline 6 engine & trans combo.
MBHD