I was looking at L76 engines before I bought. which is the aluminum block version of your engine. They were used in the G8. As noted they are a cross breed between Ls2 & Ls3. The ls3 intake is suppose to fit but you want find alot of info on your mods listed because these engines are not as known as the rest of the LS fleet. LS1 tech would be tge best place to ask mod questions on this engine. The hp numbers you quote can be achived with your engine. The 6 speed is a totally different trans than the 4 speeds before it. Unless you just want to paddle shift you would be happy with a 4l80 4 speed which will fit the tunnel without mod. But if you have purchased a complete swap engine trans harness combo you be money ahead to use the combo imo al depends on your goals really.