Hey GM what's up everyone, I am about to get my engine rebuilt soon, its a 2003 3800 N/A and I would like some help on what I can do to get about 250-300 base HP out of it. I want it to wake up a little. It's gonna get bored over .30, all new internals. So guys what should I get to wake it up N/A 3800. I'd really appreciate feedback, thanks.

 

Oh wow, just looked at your join date! Welcome back!

Take a glance at this thread here for some good ideas of what you can do. But trying to get near 300 HP out of a 3800 that isn't boosted won't be too easy.

https://montecarloforum.com/forum/engine-transmission-12/general-mod-plan-3800s-thanks-bumpin-24896/

 

Nice Find Mike!
Thanks!!!

 

Yes, I been at it for awhile. Unfortunately I won't be rebuilding my N/A, I'm goin to the supercharged swap over 😀

 

Are you doing a top swap or a complete engine swap?

 

I'm getting the complete engine, just wondering if I would need the wiring harness and computer, anyone?

 

I believe you would need the harness but i dont know about the computer. I think you might have to adjust something in your transmission to allow it to handle the added boost pressure the L67 puts out

 

Preciate it!

 

Do you have the engine already?

 

Ok: So you are going to run a full L67 and your stock NA trans. Neither stock PCM will run the combo. you will need a custom pcm from one of the vendors. the main diffs are: trans gear ratio, MAP sensor, and the boost bypass solenoid.

-Harness. not needed. you can get the two missing harness pieces for less then what you would pay at a junk yard for a harness. (boost bypass solenoid, MAP sensor)

-Either PCM can be reprogrammed or used as a core for your mail order PCM. For the power level you are after I strongly recommend a custom in car tune vs a mail order PCM.


The following is how I recommend go about the power level you are after:
-Don't waist time having the engine bored or custom internals. this money can be better spent on other mods. the stock bottom end is plenty strong for even the radical builds.

-XP cam, 105# springs, double roller timing chain, new valve seals

-Gen V blower, Headers, Custom tuned PCM
this should hit your 250-300 hp mark.

My plan to reach about 300 hp is:
stock NA block.
Ported Heads w/ Si Valves, viaton seals, L76 springs, mod'd retainers
Port matched LIM w/ coolant block off for SC
Ported Gen III 3.8" pulley
Ported L67 TB and have Northstar TB to test as well
Speed Daddy Headers
Full 2.5" exhaust
Lots of tuning.