wut would make more power or wut would be a better swap also goin to use a 4sp auto on the lt1

If both are stock, the LT1. It was rated 300hp (net) in Corvettes and 275 in other cars. The `71 402 was rated 240 net. If modified though, the 402 has the potential to make more power than the LT1 due to it's larger displacement and heads.

is there much diff in throttle response and drivability with the lt1 or just more cuz its fuel injected its nicer to have

Which would be a better swap depends on how you're going to use it... If running mid-13s is fast enough for you, and you really want modern driveability and 20+mpg then the LT1 is the better choice.

If you want to run 11s or 12s, the bigblock will get you there cheaper, however sacrificing the gas mileage and modern car reliability.

I have a '95 LT1/4L60e in my Chevelle, and have run 13.82 @ 96mph and got 23mpg on 87 octane driving it to the track with 3.08 gears. I've since swapped to 4.10 gears, and mileage dropped to about 19, but I'm expecting 12.9s with traction if/when I make it to the track again. The LT1 is completely stock except headers and programming. I intend to do a cam swap some time, but it may be a few years.

well as far as gas guzzlin dont matter maybe 2out7 days if that driven and as for power i would love to have a beast not under 12s though, wuts items i need to help my 71 396 to hit 12s