Upgrade! 86 GT with LS4 and 4T65E swap (Page 1/4)
JC86GT FEB 24, 05:53 AM
This is my first post, but I've been lurking and researching this site for a couple months now. I'll give a little backstory to this project before I get into what I'm planning.

20 years ago I bought a 1984 Red notchie with the 4-banger. Loved the car, painted it bright yellow, rebuilt the engine, and after a couple years of owning it, someone turned in front of me and totaled it out. Life goes on and I never was able to get another due to having kids and not being able to squeeze the family in one.

Kids all grown now, got grandkids even, so I'm looking for a new project and a couple months ago I came across an 86 GT, black, V6 auto but the engine has slung a rod. I picked it up with the intention to put a supercharged 3800 in it. The problem is that there aren't many around my area that people aren't wanting over $2500 for the whole car so I was losing hope in finding something local to me that I could at least verify it ran.

Last week I was performing my normal search for either an engine or a donor car and came across a 2006 GXP with the 5.3 LS4 and 4T65E-HD but the trans was slipping. I started researching the LS4 swap and I believe I can do it with a little help from the search feature or the guys in this forum. I'll incorporate my sons and grandsons help of course, and who knows maybe one of them will inherit it one day!

So I got the GXP late last week and began researching all the mods I want to do the engine, trans, and the car. Here's a short list of planned work to the car:
DOD and AFM delete
Camshaft and spring upgrade
Mild cylinder head porting/clean up
Intake manifold upgrade
Wiring harness cleanup/reroute/hide
Transmission rebuild and upgrade weak points; install shift kit
Upgrade Torque Converter and install external trans cooler
Upgrade radiator
Upgrade fuel pump and fuel injectors

I'm looking at the Texas Speed Stage 2 cam- 212/218 .550/550 camshaft and beehive springs. With the other work I'm planning I'm shooting for 400-425HP.

So, I know this won't be a project I finish overnight and I plan on doing as much of it in-house as I can. I've seen multiple project builds on here start off great and lose steam as the project drags on too long, so my goal is to have the car back on the road running by the end of 2021 so I don't lose steam on it, but that just depends on what life throws at me next year; we had two major Hurricanes in 2020 that we're still recovering from so I'm hoping 2021 is going to be better!

I'm going to try to take pics along the way and post regular weekly updates and will be looking for the members of this forum to provide advice along the way if you see me going down the wrong path.

And with that, here's a pic of the donor car and in the background is my dust-covered GT. GT, meet GXP. Next step- remove the engine/trans from the GXP!
Rickady88GT FEB 24, 11:52 AM

quote
Originally posted by JC86GT:

And with that, here's a pic of the donor car and in the background is my dust-covered GT. GT, meet GXP. Next step- remove the engine/trans from the GXP!



I hope you post lots of pics and info. That is where I failed in my swap. You will basically be documenting or authoring your own shop manual for future reference.
The LS4 was a fun swap and a BLAST to drive. I have said many times that I wanted the sound of the LS v8 more than any other benefit from the swap.

The GXP had the Tap Shift option, did you get that with this car?
Have fun, be safe.

[This message has been edited by Rickady88GT (edited 02-24-2021).]

JC86GT FEB 25, 12:40 AM
Yes; the car has the tapshift option. I'm not too sure about using it in the GT though; I've read it's a potential weak point using it because GM really didn't build the transmission properly for shifting manually, but I still need to research that some more. The car also has the HUD, which I'd love to figure out how to put that in the GT... would likely require a complete dash upgrade, which is something I'm interested in, but for now, my focus is getting the engine/trans in the car and running. After that, who knows.

So far, I've not been able to even mess with it because I'm stuck on nights at my job, but that should end soon and I can start turning wrenches. The cam I've selected is a Scoggin Dickey SDR55308 with 204/222 duration and 551/570 lift and a 112 LSA, which requires a beefier spring kit. On a 5.3 truck motor, it made 430 HP and 426 TQ, so with my car intake (unknown right now what to use) should get me around 415-420 HP. I think 42lb injectors should get me enough fuel for that power range, but again, more research needed there. I'd love to get a FAST LSXR intake, but I don't have any spare body parts to sell to afford that right now. I know I'll have to modify my valley cover to facilitate a different intake manifold, but that will be easy. Just trying to find something I can afford and will fit under the deck.

I will likely do some Youtube videos as well, as I know pictures just don't capture everything.

I guess one big question I'm trying to answer is do I want to have someone else program the PCM, or just get HP tuners and do it myself and then have it for tuning later. This is my first foray into modern computer controlled engines really, always just done old school with carburetors, so I've got to educate myself some more on that stuff too.
Dennis LaGrua FEB 25, 10:30 AM
If you have the paddle shift option you will most likely have to retain most of the drive by wire features of the original PCM. I've never done this swap so Fieroguru might have a better answer.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

Trinten FEB 25, 01:04 PM
If you haven't bought your DoD Delete stuff yet, LSXceleration ( https://www.lsxceleration.com/ ) is where I bought a lot of my parts from. They were really great to work with. I hard ordered a number of other things, including one of their full "replacement seal" sets. They called me and said "Hey, you know between the DoD delete and the kit you bought, you would have wound up with two of <item, item, item>, so we're taking the cost of those off your bill and refunding it."

They also didn't have something in stock (I don't recall what right now), so they gave me a free upgrade to the compcams version of it (so maybe it was valve springs?)

Anyhow. Really pleasant people to work with. I had called them on a number of occasions with questions, and even when they could have upsold me, they took time to understand my project and power goals, and would make a good recommendation.

They also have a fantastic trunion upgrade kit that my builder strongly recommended. Let me know if you need any part numbers!
JC86GT FEB 25, 09:51 PM
Thanks for the tips! I haven't bought anything yet. I'm researching what parts I believe I will need. Some folks just buy what looks good or what other builds used; I'm a lot more analytical in selecting my parts to ensure they work with one another so I'm taking my time.
JC86GT FEB 25, 09:58 PM

quote
Originally posted by Trinten:

They also have a fantastic trunion upgrade kit that my builder strongly recommended. Let me know if you need any part numbers!



Let's see them part numbers!
Trinten FEB 25, 10:40 PM
You got it!

Here is the "important stuff" -- I got other stuff, like clevite coated bearings and such, but that's easier to find.

Dual valve spring kit with tool steel retainers - 80540K1TS

Gen IV LS DOD/AFM Delete Kit - DOD-Delete (yes, that is their sku, when it comes up, they have a LOT of options to customize exactly what you want. I got all sorts of goodies with mine). Things I tacked on:
16 (full set) COMP #850-16 Lifters
ARP Replacement Head Bolts
Valley Cover w/o PCV 12598832
Intake/Exhaust gaskets
GM Crankshaft bolt 12557840

LS Rocker Arm Trunnion Upgrade Kit 713702-KIT

GM LS Lower Gasket Set CS5975A

I appreciate wanting to buy the highest quality one can afford. That's how I do it too. I ask all sorts of questions and do a lot of reading, then ask people I trust for their opinion (FieroGuru is super awesome and patient with all the stuff I've asked him over the years).

[This message has been edited by Trinten (edited 02-25-2021).]

JC86GT FEB 25, 11:41 PM

quote
Originally posted by Trinten:

Valley Cover w/o PCV 12598832

I appreciate wanting to buy the highest quality one can afford. That's how I do it too. I ask all sorts of questions and do a lot of reading, then ask people I trust for their opinion (FieroGuru is super awesome and patient with all the stuff I've asked him over the years).




Appreciate the info; already checked out their DOD delete and will save me a few bucks over the one I was looking it with similar options.

On that Valley cover w/o PCV, I just started researching it, but how do you vent the crankcase w/o the one on the valley cover?
Trinten FEB 26, 01:20 PM
That is a great question and one I can't answer! lol

When I asked Mike (the guy doing all of the hard work on my build) if I should get one with or without it, he said without. I didn't think to ask him why. I am running a turbo too, not sure how that plays in. I will ask him next time I talk to him (either tonight or tomorrow) and let you know!