V6 F-Body.com

V6 F-Body.com (https://www.v6f-body.com/index.php)
-   3x00 Specifics (https://www.v6f-body.com/forumdisplay.php?f=70)
-   -   4 - TKOFORPRESIDENT'S 3x00 Build - Modifications List/Procedures/Pics (https://www.v6f-body.com/showthread.php?t=3274)

tkoforpresident 03-28-2011 02:38 PM

4 - TKOFORPRESIDENT'S 3x00 Build - Modifications List/Procedures/Pics
This thread will entail all of the modifications necessary for my hybrid build from large to small, with pictures and procedures being documented along the way.

*This list will be continually updated with new information as things progress.


- 3500 LIM coolant passage tapped for CTS

- Tab on top of TCC must be cut off to allow space for 3500 LIM

- Alternator shaved a bit to allow proper fitment of valve cover

- Accessory brackets modified to allow proper mounting to heads

- 3400 UIM Lettering shaved off to allow fitment under cowl

- Modify injector harness

- Pacesetter headers need to be modified to fit 3500 heads (bolts holes need to be slotted)

- Heater core hose modified and routed to the back of LIM

- Vacuum Hoses re-routed

tkoforpresident 05-12-2011 12:19 AM

Tapping the 3500 LIM

OK, let's get started with one of the modifications necessary to get this thing done.

The 3.4 has TWO coolant temperature sensors (located in the LIM and drivers side Head) The sensor in the LIM feeds the coolant temp to the PCM while the one in the head feeds the crappy/usually off by 25*F or something ridiculous- dash gauge.

The 3500 LIM has CTS bungs located in the LIM (left side of the thermostat neck). This is where we are going to run the PCM CTS from. The only problem is that now we don't have a spot for the dash temp gauge sensor so we have two options:

1: Use a 3 wire CTS in place of the 2 wire sensor and splice into it with the dash gauge reference wire or..

2: Tap a second hole for the other CTS.

It just so happens that the 3500 LIM has an "extra" coolant inlet located on the OTHER side of the thermostat housing. We would need to cap this somehow anyways since it will not be used in the build so we will kill two birds with one stone by tapping it for a second CTS.

I picked up this tap set from harbor freight for ~ 15$


The inlet is 1/2" in diamater so you will need to use a 1/2" NPT tap. I used a 6 point socket on a 1/2" socket wrench to turn the tap. Wd-40 is a good lubricant when working with aluminum and you will want to be very liberal with the application of it.

Turn a bit at a time and when it gets tight back it out and then rethread it back in again. Once you have 7 threads left at the back of the tap then your done, there is no need to go further.

CTS's are generally 3/8" NPT so we are not done yet. You will need to go to home depot and buy a 1/2"~3/8" NPT reducer. Get brass (galvanized will corrode with aluminum). Also, pick up some thread sealer/tape while you are there.

This is how the threading should look when you're finished:

And the reducer installed:


Now, I'm not *positive* that the stock sensor harnesses will reach the new sensor locations but they should at least be very close.

tkoforpresident 05-12-2011 01:04 AM

Shaving down the 3400 UIM

This is a fairly straight forward procedure.

We need to grind down the "3400 SFI" (or 3100 if you have that upper). This needs to be done so the intake can fit underneath the cowl of your 4th gen f-body and to prevent unnecessary vibrations through contacting the cowl during acceleration.

I clamped down the intake to keep it steady while I went at it with the grinder. The aluminum comes off pretty quickly.

You can see the finished product here:


Hey, I know it's ugly but I'm planning on painting it anyways.

All times are GMT -4. The time now is 11:29 AM.

Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
2008 - 2019 V6F-Body.com