Ok what would be the best engine transmission swap to use in a third gen?I am interested in fuel economy and performance.Also which rear end ratio to run?tell me where is the best place to get the engine etc...and some ballpark estmates of engine trans cost.has to be a v-8 and 6 speed manuel.Again thanks guys your knowledge is priceless.

 

That's easy. If cost isn't a problem, just something to keep track of, then there are plenty of LS1/T56 combos out there returning 31+ mpg at a steady cruise on the interstate. This means a "baby" cam, and 3.42:1 rear gears, but even so, high 12s are possible on street radials.
If you have a budget, but it's generous, the next step down would be any of these 3 engines: LQ4, LM7, LT1, again with a T56, and 3.42:1 gears except the LM7, which would do better with 3.73:1.
From there, I'd say the next step down would be a new L31 crate engine, again with a used T56 from an LT1 F-car.
Used T56s go for around $1200, used LS1s go for around $2000, new L31s go for around $2300 (seems to contradict what I already typed, but remember the cost of the swap) used LQ4s go for around $800, and used LM7s go for around $500.
Figure about $1000 for a complete, good exhaust system no matter which way you go.

 

Thanks buddy i really appreciate info!Its amazing how much guys know!

 

Honestly, I could have typed much more, but it'd be so much to process. And others will be chiming in tomorrow with conflicting prices and rankings, and even different options. I left out an awful lot, but I think it's best to pick an engine family first. The SBC family is far cheaper and easier to swap in initially, but is potential-limited. The LSx family is far more wiring and so on, much different fuel, cooling, mounting and exhaust systems,.

 

Attila,

All the engines you mentioned sit inside a thirdgen camaro with no modification on the mounts?