[dezldave961]

You'll need to get L67/L32 s/c heads to finish it up. They're not hard to install after cleaning them up and prepping the gasket surface. Bolts/gaskets are about $50-75 for stock/Felpro style, which works great on most builds of this type, including my own s/c engine.

The 2-bar MAP from 2003 & older are the flat rectangle style that needs an adapted harness (or rebuild yours with the new connector). The 2004+ cars got a 2-bar MAP that looks just like the L36/L26 ones, just a different part number. I run a 2004+ sensor in my turbo build, so it looks stock on the intake, but you can use either for a s/c setup.

ZZP sells the connector for $15 to run the rectangular sensor (or a plug-n-play adapter harness for $50, I guess). You'd just need to make the connections and peel back the wire loom/tape on the harness a bit to mount it on the rear of the s/c like an L67's.

Here's an L32 2-bar that came on a 2004 GTP engine I just got. There's actually two on each car, since they also have a barometer sensor next to them, open to atmosphere.

 

[dezldave961]

The $50 kit from ZZP is mostly unnecessary, since you just need the MAP connector... (especially the boost bypass solenoid... We post about it probably 2-3x a month here, so I'll have to start copy-pasting in the info).

The heads are necessary for this swap to be completed the typical way, along with new rails (either find L67 ones used somewhere, or aftermarket logs from ZZP/classifieds/Aeromotive).

Connectors are the same (3/8" and 5/16" GM quick connect), it's just the routing of the L36 ones with the 90-degree bends make the routing a bit of a pain. Dorman has new straight-end hoses you can swap to, that are sold in stores cheap. They come with 18" of line to cut/replace your original ends and make them end in the right spot. I've played this game a couple times, and there's a variety of options.

 

[dezldave961]

Bottom line: buying an M90 ≠ having what you need for a top-swap. You're basically turning the top half of your engine above the block/pistons into an L67 with slightly higher compression. That's why there's a list that's pretty common on every 3800 site dealing with this.

That Milzy kit is the patch-worked way to do it (clamps & hoses, etc.). Those $10-15 Dorman parts hanging in the aisle of your local Advance/AutoZone are an easy process to do it correctly with OEM-style quality.

From ZZP, you'll need an L67-style rail if you don't have their custom-modified lower intake that adds L36 injector location holes to avoid swapping heads out. This is an oddball part, which is why I'm suggesting not chasing that path, in favor of the more universal and cheaper path of getting used OEM swap components.

The clips holding your injectors now are the same as the L67 uses, only your electrical connection may need adapting for that item. Those ones securing the quick connects will work on either GM rail.

There's no need to rebuild L67 heads to install them. If you buy some in good running condition, they can be installed as-is with a fresh gasket/bolt set. Being cast iron heads going on a cast iron block, they only require machining/prep for modification or porting, since warping only tends to occur under severe overheating issues.