Top swap while doing LIM?

**Brammer** · 10-22-2013

I know my car needs the LIM gasket replaced, with 145k on the clock it's a ticking time bomb for coolant/oil mixture to invade. It seems like if I have to tear the plenum off and the lower intake manifold I might as well do a top swap. I know that for a N/A I will need at least headers to avoid KR. My big concern is tuning, there is no one near close to me that can tune it in car. Southern Virginia doesn't quite specialize in proud car owners so shops that can tune are an abnormality. Is there anything that could be used to record data values so someone like Overkill could tune a PCM for me or do they have to be in the car etc? Further more how much of a chance does my non-hd transmission stand lasting more than 10 minutes with a top swap?

**dsmuts** · 10-22-2013

You realize you have to swap the heads to right?

**DanPrixGTP** · 10-22-2013

For your tune, contact Overkill to get one or you can also purchase a tune from ZZP or 3800performance. You do not need to have your car their. They can send you a tune through the mail. But you may have to send them your PCM, I believe.

Yes, you should get headers while doing a top swap. Since you have a high compression block, you'll more than likely see more KR on stock manifolds than a typical GTP.

Your non-HD trans will work.... for now. Be prepared to set some money aside to have it rebuilt with some upgraded parts. These transmissions are built with tinker toys and break all the time. Take me for example, my trans had to be rebuilt twice, when I was stock. But the Non-HD trans is almost identical to the HD trans.

Lastly, Dan is right, you need to swap the heads as well when doing a top swap. NA heads will not work. Go pull a pair of heads off a GTP from your local junkyard.

**dsmuts** · 10-22-2013

Non hd trans is the same as the hd trans aside from gear ratio and differential

**Brammer** · 10-22-2013

Did not know I needed to change out the heads. Well that's a bummer. Looks like I might just do the LIM Gasket, Plenum Gasket, TB Gasket, Coolant Elbows and maybe an HV3 insert or something.

**DanPrixGTP** · 10-22-2013

Heads arent that difficult to pull off. Its like 8 bolts per head.

**Brammer** · 10-22-2013

My biggest concern is the tune. I know a 'can' tune is not ideal by any means for a top swap.

**MoarkatsINmuhtrailer** · 10-22-2013

You need:

Supercharger
L67 Lim
L67 heads
L67 harmonic balancer(crank pulley)
L67 coilpack bracket
L67 accessory drive tensioner and idler pulley
L32 map sensor
New belts
Refresh some more stuff like radiator hoses, coolant elbows (aluminum replacements are preferred, Dorman PN# 47065hp)
Headers or plog/downpipe.
Tune
May as well do an oil change or two (cheap ones too)

**Brammer** · 10-22-2013

I assume I would also need/want a Aeroforce as well to make sure it's done up right.

**MoarkatsINmuhtrailer** · 10-22-2013

It is a good tool to have

**Brammer** · 10-22-2013

How would headers run/affect performance on a N/A 3800?

**DanPrixGTP** · 10-22-2013

You dont want headers on a NA if your stock other than that.

**MoarkatsINmuhtrailer** · 10-22-2013

Dan if you start with that backpressure bull**** I will flip a ***** on you

**DanPrixGTP** · 10-22-2013

Don't know what you're talking about

**Brammer** · 10-22-2013

Well if it's not the top swap route, I'd probably just do the LIM gasket and put an HV3 in and then maybe ported manifolds, downpipe etc. just generic air/exhaust mods.

**Brammer** · 10-22-2013

Wait a minute, I'm an idiot. I don't know what I was thinking. The valves and everything are contained inside the heads, they just drop right on with new gaskets don't they? When doing the LIM gaskets or the top swap, do the injectors need new o-rings?

**DanPrixGTP** · 10-22-2013

Yes, GTP heads just bolt right on. Pull off NA heads, bolt on L67 heads. With new head gaskets, of course.

Injectors do need new o-rings. Why? Because they are very cheap, and you do not want to take a chance with a fuel leak.

**Iceman6669** · 10-22-2013

Who is talking Back Pressure??

**Brammer** · 10-22-2013

Well hell, I might piece this together over the winter and do it in the spring when I can use the bike as a daily driver. Yeah I've heard one too many horror stories of engine fires from pinched o-rings, I'll gladly replace injector o-rings. On a related note, are the Speed Daddy headers the ones that can be found on ebay for ~$250 or so?