Okay well please bear with me lol I'm still learning.

So basically what I am supposed to do here is
get a 'new' 3800 Engine (the one that came with my Monte)
and then basically add the Super Charger parts on top of the engine from the L67 (AKA Top Swap)
???

Because I found a rebuilt 3.8 for about 900 and my mechanic would install it, the only real trouble I'm having is finding the L67 Supercharger parts. No one seems to carry it.

 

4t65 and 4t65e are the same thing- people just leave off the e sometimes because its easier to say, and still conveys which trans it is. The e just means it is electronically controlled (which is common to all of our transmission now, so its no longer a very important designation).

The main difference have already been stated above, the 4t65hd has an upgraded differential, lower chain/sprocket ratio that is usually 2.93 (compared to the normal 3.29 in the regular 4t65), and a larger torque converter. Other than that, the two transmissions are pretty much the same- they're both the middle of the line FWD transmission in the GM line (with the 4t45 being lower, and the 4t80 being the higher).

Since both transmissions carry the same "65" designation- they both are rated for the same gross vehicle weight of 6500 pounds (not surprising since they share about 95% of the same components)- and strength wise they seem to both hold up about the same.

I believe the reason why they built the HD version is because they were having problems with excessive wheelspin destroying the differentials on regular 4t65's with the L67. As long as you avoid burnouts (especially letting 1 wheel spin faster than the other)- both transmissions seem to hold up about the same.


IMO you have 3 real options:
-buy a regular used L36 (and forget about modding it- or add a turbo later)
-buy a regular used L67
-buy an L36 bottom end, and an L67 top end and do a "top swap"

If you're having a mechanic do the work- I wouldn't personally try to get into the top swap thing- as they usually overcharge for 'custom' work (even though its bolt on). I'd either just buy a straight L36 or a straight L67 if you want the extra performance and modability.

IMO scrap the idea of buying a rebuilt 3800, the failure rate is MUCH higher with them, and the 3800 is so common, there is no real reason to buy something that has been rebuilt. Its not like its a particularly rare engine or anything.

As for parts- the 4 places I would try are:
-ebay (worth a shot, sometimes cheap engines go through there)
-Morad Parts Company (a junkyard specific to the 3800 cars, they will have everything you need, buy you will pay a little premium for them having it)
-clubgp- look in the classified section, yesterday there were 3 threads on the first page alone offering complete top swaps.
-3800pro- look in the classifieds (sometimes you get stuff on there that isn't cross posted on clubgp

Between those 4 sources and local junkyards as a last resort- you should be able to find every possible 3800 part you could need.

 

Bumpin was spot on in his response in my opinion. I do want to add on to that a bit though. The 3800 motors can do 200k miles when maintained properly. There are plenty of these motors around under 100k miles, and many well below that. Finding one that has plenty of life left and doesn't need a rebuild isn't hard at all. As far as the top swap, from what I've read there can be issues with the bottom end after this is done. Also simply swapping the entire engine and trans for a L67 with the HD trans gets you the entire top of the line package vs having a L36 and non HD trans with an L67 top end.

Finally having seen the Morad facility I wanted to comment. Unlike junkyards I've been to, everything at Morad is stored neatly in a warehouse and not outside. It's not like they would be out digging through a bunch of cars in a field looking for the parts you need - everything there is well organized.