RHRose,
I assume that you intend on puttin a chevy in your snake. If
so I would recommend the LS6. There's more power per
cubic inch than any motor out there. It is also a very good
daily driver and the gas mileage won't kill you either.
The best kit depends on how big your wallet is and
which style of cobra you like. ( 289FIA, 427SC, slabside, etc.)
It also makes a difference as to your building skills. Some kits
are a little easier to build than others. A good rule of thumb
is the less you pay the more you have to do.
Use the search function here and you will get all kinds of
info on the various kits.
Hersh
