So im sure someones already posted this kind of question before but after browsing forums i couldnt find it so im just goin to ask anyways. i have the intake, wiring harness, injectors, pcm, supercharger (M62), and other random parts of my series 1 3800. attempting to supercharge a series 2. i know the lower end of the motors are different, while same bore stroke, theres like an inch difference in pushrod length and yada yada yada. would series 1 heads work on series 2 block? is there deck height differences? would it physically bolt up even if lifters and all that would be wrong? another question is would intake from series1 work with series 2 sc or non sc heads? i know the M90 has a much bigger extension to reach the belt, but this is due to placement of intake right? and i heard only difference for the wiring harness between series1sc and series2 sc is maf or map and transmission. ive already dropped a 4t60e from my series one and connected it to my series 2 which i believe had the 4t65? its not that big of a deal if you have a wiring diagram to rewire the connector. just tryin to learn a bit, any information is appreciated, i know, stupid questions, stupid answers, but lets try to keep them to a minimum thanks guys.

I do believe the intake manifolds fit differently. Someone in my top swap for sale thread told a member with a S1 it wouldn't work since its an S2 kit so it probably won't work the other way around either.

The quick easy answer is no, the heads don't fit. And for the price of the S2 stuff these days, it'* not really worthwhile fighting the battle. If you need stuff low cost, holler. I know a buddy that sells top swaps for $300 complete.

The deck height is in reference to the block. The series 1 deck is 1" higher, so everything changes. The width of the lower intake manifold is different because of that 1", and that'* not even your biggest problem. The pushrod lengths are different, and the biggest deterrent from ever trying this is that it uses a different cam. The valve order is different so you'd have to get a custom cam ground to fit, along with the custom lower intake manifold.

One guy I know of with a custom dual-engine w-body Cutlass supreme was working on a project for fitting Series 2 heads on a Series 1 block. There are advantages to the taller deck height and the better flowing Series 2 heads, but he stopped at trying to make spacers for the maniold and getting a custom cam ground. I have no idea how far he'* gotten now since we haven't heard from him in 2 or so years. Getting Series 1 heads onto a Series 2 block is the worst of both worlds. The s2 heads have larger valves and flow much better than the S1 heads, so you'd basically be creating a bastard of a motor that would be weaker than just pulling a supercharged Series 2 from a junkyard or top swapping yours.

Don't expect the 4T60E to last very long with a supercharged Series 2.