A STOCK cam benefits from tuning the stock cam is 191/195 the Comp 306 is 230/244.
The factory rev limit in first gear is 5500rpm(lower in higher gears), if your heads are decent the Comp 306 wont even peak till 6500. Now aside from the fuel and spark tables being all wrong for the cam change below the 5500rpm stock rev limit how well do you think a cam would work keeping it limited to 1000rpm below it's peak power?? Understand that to properly use a cam you need to rev several hundred rpm past peak power so you use the whole top of the power curve.
The valve sizes you listed in the other post suggest either you or your machinist don't have a clue, I do not believe the seats can be cut that big in GM heads and if they could be you wouldn't want to anyway, the fastest NA b-bodies are running 2.00/1.55 valves and the fastest 350 car is running less duration than you are proposing, my car runs less duration than this and it is one of the quickest truly street b-bodies.
Computer tuning would be needed just for the boltons to support the 306 cam, with a cam that big you would absolutely need high stall and in a wagon I would say 4.10 gears. Need a lot more other mods but those need reprogramming for.
This is all besides the fact the 306 is a dinosaur of a cam well known for it's tendency to surge even with reprogramming, this is marginally a better choice than the one you picked out last time but still way way out of line. If this is a street car I might aim for 32-3400stall 3.73s and something down around the Comp 503 as the max for a wagon.
If shopping Comp's catalog understand the rpm ranges listed are based on Gen1 stuff so they are several hundred rpms lower than a LT1 will need to turn, that Comp 503 cam I mentioned has a listed rpm range of 1800-5800rpm in practice guys with ported heads routinely turn it 6300-6500rpm.
Best guess as to why the rpm ranges are so bad is the LT1 intake's short runners favor high rpm.
A car needs a LOT of work before looking at a cam, being 16+yo cars fuel pumps should be upgraded, sometimes injectors upgrades are needed, need a good CAI and new exhaust from the manifolds back. Tranny rebuild is prudent, a stall and gears are absolutely necessary. Gears often make upgrading the driveshaft to an aftermarket one balanced to a higher rpm a good idea.
Then far as trying not to retune, things like larger injectors without reprogramming will actually destroy the engine, reprogramming is a critical part of performance modification.