Building supercharged M42, looking for advice

[Damatheus]

Hey all.

I've got a 1977 320i (E21) that I am going to swap an M42 from a 1994 318i into. My plan is to build the M42 top to bottom and add a supercharger. Looking to get as close to 300hp as I can and still be streetable.

I am good with wrenching and working on cars, but I've never done much with motor work so I'm new to the building process, bear with me.

My plan is for new pistons, rods, valves, springs, cams, light flywheel, and a supercharger and hopefully a WAR chip if it is compatible?

I have been shopping around on the VAC motorsport website and they seem to have everything I would need, despite what seem like high prices.

So, a few questions.

First off, where else other then Metric mechanic and VAC can you find M42 performance rebuild parts?

What is reasonable boost?

What would be the best compression?

What is the best route to get the M42 up to 2.0L?

Any other advice appreciated!

[bme30]

Ive done a lot of research into sc the m42.  I was going to keep the motor stock internals to start.

The dasc uses an eaton m45 sc for their bolt on kit.  Now if you were to find a m60 or m90 sc you can use a bigger pully on the bigger sc so you can get the same psi as the m45 but at lower sc rpm.  This helps reduce heat soaked sc.

A good set up that ive seen was using the m90 sc from the ford thunderbird supercoupe.  The set up uses the m90 before the tb kinda like a turbo set up.  The m90 from the ford is shorter than the eaton m90 used by gm in the grand prix/bonnaville.

As for building the motor, i would up the cams, and leave the stock pistons.  For you up the cams and lower the compression.  I dont think you really need to bore the motor as the sc will add a lot of tq your way.  But thats my opinion.

Good luck and hope that helps!

[Damatheus]

Thanks for the advice on the different superchargers. Giving that I want to run high boost, having a larger SC will probably be the best bet for me.