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'96Bonnevillel67 wrote: Off topic, but why would you run at the track with about 150-200lbs extra in your car?

01bonneSC wrote:....and thats pushing 4000lbs with me in it....

It doesnt drive itself down the 1/4.....

'96Bonnevillel67 wrote:Swapping heads to the STS heads, should run a 14.5ish completely stock in say a '96-'99, seeing as many have hit 14.8's in stock 4,200lb STS's.

The LC3 supercharged N* in the 06-09 STS-V puts out a respectable 469hp and 439 lb.ft. So if your looking to mod one, maybe a heads up swap with LC3 parts is the ticket?

Doesn't that blower use a front inlet though? Hard to work in a transverse setup. Turbo would be a better bet.

1fatcat wrote:

'96Bonnevillel67 wrote:Swapping heads to the STS heads, should run a 14.5ish completely stock in say a '96-'99, seeing as many have hit 14.8's in stock 4,200lb STS's.

The LC3 supercharged N* in the 06-09 STS-V puts out a respectable 469hp and 439 lb.ft. So if your looking to mod one, maybe a heads up swap with LC3 parts is the ticket?

Those parts are going to be EXPENSIVE, more than the car it's going into I would guess. Due to the cars they go into, and rarity of said cars.

ChilinMichael wrote:

'96Bonnevillel67 wrote:Swapping heads to the STS heads

Err...I'm pretty sure the two variants (300/295 vs 275/300) are computer related, not physical. It's like a Mark 8 with the Intech, it's been tuned over the years to have different performance numbers/levels..but all boils down to the chip.

This is off topic but not at the same time. If the OP decides to do a N* conversion, at least he'll know he can tune it to some small degree...

I've searched and searched and every single thing I read backs what I thought, there's no head difference, just a tune. Improvements over the years included refining the intake, tune, etc.

*NEWSFLASH*

Nobody has cracked the GXP PCM yet. Some have offered, but the price was too high.

'96Bonnevillel67 wrote:And I ran a 14.7 with just an intake. That's not the point. Swapping heads to the STS heads, should run a 14.5ish completely stock in say a '96-'99, seeing as many have hit 14.8's in stock 4,200lb STS's. Add intake and exhaust, maybe a few other small things, and you're looking at low 14's, possibly scratch a high 13 for a couple hundred $$$. Seeing as he has the motor already, it won't cost him much more besides time, and not have to worry that he can drive home because his trans. took a dump.

Off topic, but why would you run at the track with about 150-200lbs extra in your car?

Oh yeah, what car did you run that time in? And researching used heads for and STS, all i could find were 6 popper ones and places wanted 600 just for ONE.

Wren made a very valid statement which essentially kills any hope for practicality in swapping to a Northstar.

Also, the S/C STS (Which is an STS-V) uses a VARIANT of the Northstar, which is 4.4 Liter...will the heads fit? Better look into that first....not to mention...slapping them on without an S/C? Who could say for sure what you'd even get...

Why not just stick with the 3.8...proven performance and known answers (not to mention the savings in your wallet)



P.S. This topic is starting to hurt my brain...

J Wikoff wrote:Just about everything available for the SII is available for the SI.

Except time slips


If the N* is available, try considering a sonoma/fiero rwd project, if you are dead set on using the engine. The internet is great help as there are right ups on people completing these projects.

its a different engine it will not fit..

the LC3 is a 4.4 were us with GXPs run a 4.6..

and as mentioned above.. no one can tune a GXP pcm..
good luck....

SAMzGXP wrote:its a different engine it will not fit..

the LC3 is a 4.4 were us with GXPs run a 4.6..

and as mentioned above.. no one can tune a GXP pcm..
good luck....

Not a quite, Gen III/IV Chevy (LSx) series heads are pretty interchangeable, And they come in 5.3L to 7.0L displacements. Not all work on all motors, but there are a few swaps.

In reality it's more the LIM/SC and intercooler one is worried about. The Supercharged northstar has a very tall height because of the intercooler setup being above the SC, A northstar with a normally aspirated intake manifold is already at the hoodline, with a GM parts bin blower setup you'd have to seriously do something about motor height, whether it be lower the power train, make a giant hood, or combination of both.

If someone is spending that kinda money on an engine swap... You've got the wrong car first of all (get something better, ATLEAST an F body) and you might as well run an LSx motor as they're pretty much limitless as far as power goes, and bolt up to the 4t6x in our cars easily enough (still have to futz with accessories.

Northstar swaps can be pretty *dang* cool in a hot rod, there are alternative ways of running an engine where you can tune, but you're looking at a piggy back ECU at a miniumum (Greddy E-Manage) which would be a MAJOR PITA, or a standalone like megasquirt. MS would be better in the long run, and is very usable for different applications down the line, boost being one.

A Northstar could be sweet, but if you have to ask...

i really doubt you can swap parts that easy from totally 2 different motors

LD8 in the GXP and LC3 in the STS-V

Larz01 wrote:

J Wikoff wrote:Just about everything available for the SII is available for the SI.

Except time slips


If the N* is available, try considering a sonoma/fiero rwd project, if you are dead set on using the engine. The internet is great help as there are right ups on people completing these projects.

My Series 1 PB is quicker than your S2 Bonneville was, and not far off your much lighter GTP.

This topic is about a guy that has a bone stock Northstar engine and was wondering if it would be a worthwhile swap into his car in place of the 3800. How did it go from that to swapping out heads and adding a supercharger? There was no mention at all of mods yet we are discussing modded Series II L67s against a stock Northstar. Now even the Series I is being drug into this.

I said earlier that swapping in a Northstar being a downgrade is pure opinion and I still stick by that. However, I would like to add more to that statement and clarify what I am saying here. Whether or not it will be downgrading depends on what you ultimately want out of it.

1. If you are after having an engine swap that nobody else has (yes, I know they are already in the GXP, but they are not in the SSEi). 2. If you want the beauty of the V8 rumble, but are also fine with a basically stock engine that will pretty much be on par with what you already have 3. If you are willing to accept the difference in fuel efficiency.

If you can accept that and have the parts laying around including transmission, axles, wiring harness, and PCM for it, then go for it.

However, if you think the mod bug will hit someday and you want to make your car a lot faster, sticking with the 3.8 would really be the way to go.

Basically, swapping in the Northstar would leave you basically at the same level of performance you are right now, it would give you a sweet engine swap and the V8 rumble, but it would also take some time and money.

Downgrading? That is up to you.

I think the last post sums it all up yet again... This thread is done..