L67 mods question

**slims00ls1z28** · 05-19-2012, 11:17 PM

I'm trying to build a mental picture of what I'm going to need for this L67 I acquired. I figured I only need 350ish RWHP out of it to be plenty quick. Not building a wheelstanding 1/4 mile burner just a fun quick car that I can do a little autoX fun in (87 Fiero GT). I prefer the blower whine to a turbo so I'm keeping the M90. I know there's alot of 3800 sites but some are blocked from work so I'll ask here first. Will a stock rebuild kit with new (stock type) pistons be fine at this level for my intent? I really do not want to sink 600$ on forged pistons, unless it is a must. I already guessed ported blower and heads, exhaust, tune, valve springs, and probably going with the short stack intercooler. Which cam/pulley size is needed for this hp level?

**Smittro** · 05-21-2012, 10:01 PM

Stock pistons will be fine, con rods are forged from factory.

May want to go with some clevite mains and con rod bearings, as they are the most commonly used in FI v6 apps.

I can't quote you a cam as I'm not familier with all the after market profiles for the L67 (ima dohc kinda guy).

I can tell you if you have'nt found out yet all 3800II's use a factory roller.

A popular pulley is the 3.4, I'd recommend some better rockers, 1.7 or 1.8's depending on lift.

Other than that your bases look pretty well covered.

Stroker kits are also available to the 3800 as well.

**Smittro** · 05-21-2012, 10:09 PM

May want to shoot GTP231 a pm as he may be able to give you some cam pointers and so forth.

He used to run his L67 GTP @ the track and he's also a tech.

**ls1camino** · 07-22-2012, 08:13 AM

Here is a quick mod list. I put this together when I was going to mod my GTP, but I ended up going Twincharged instead. I'm currently selling off what I already bought.

Gen V M90 (off of the newer GTPs)
2.8, 2.9, and 3.0" pullies (there is nothing set...you need to play with it on the dyno)
Gen III to Gen V TB Adapter Plate
Ported TB
XP Cam
105# Springs
Modded Retainers
Double Roller Timing Chain
Intercooler Setup
42# Injectors
Upgraded Fuel Pump
Fuel Pump Hotwire

There are a lot of little things, but these are the main things.

**GTP231** · 07-22-2012, 03:15 PM

Also stock pistons are hypereutectic. Though supposedly a few forged factory bottom ends exist like OE aluminum heads. Series 3 rods are powder forged which are a bit stronger than stock Series 3s.

What cam is in the current engine Jeremy?

**ls1camino** · 07-22-2012, 03:53 PM

L32 motor with ST2 cam and 105# springs.

I have a set of IS4 heads, ST5 cam, 130# springs, and a meth injection kit sitting in my garage for when I get tired of only 500fwhp.

**GTP231** · 07-22-2012, 03:55 PM

Take the IS4 heads somewhere good so they flow some real numbers...
500 sounds optimistic for your current set up...

**ls1camino** · 07-22-2012, 04:21 PM

Originally Posted by GTP231

Take the IS4 heads somewhere good so they flow some real numbers...
500 sounds optimistic for your current set up...

Really? Ive heard/read that those are some of the best heads.

T67 turbo is bigger than most people that just slap a turbo on N/A GPs and they make 425hp. I bet I can at least touch 475.