you can find a 6.0 for under 1k. add heads and cam and your way above the power of the Ls3 for alot less money. for the money you spend on the 377 you could have a built 6.0 turned 377 for the same price and have better power

or if your stuck on using the Ls3 heads and intake you can toss those on a 6.0 and still be cheaper and have same motor essentially