'67 GTO LS3 Swap

[CFster]

Hi, we have a '67 GTO with the stock 400 and a 4L60E we installed a few years ago. Now we want to put an LS3 in it.

I've done a bunch of research, and have picked most of my parts. However, there's a few things I'm not entirely clear on. I've scoured many threads on Chevelles, and some GTOs (but mostly different years than mine). I know there are differences...

1. I'm intending on running the stock gas tank, with an external Walbro fuel pump and filter/regulator. Do I need to run some sort of evap system? Purge or vent solenoid? Evap or charcoal canister? Doesn't the LS3 have provisions for this (evap line coming off the motor)? I know the LS3 harness has pinouts for those items.

2. What is the benefit of going with a SpearTech harness rather than the GMPP harness? Are either of these programmable?

3. Will the stock manifolds that come with an LS3 crate motor work in a '67 A-Body? I'm guessing not!

4. If not, how do the Edelbrock short headers compare to the stock manifolds performance wise? I really don't want full length headers and I'm aware there's a power trade off. What other options are there for short or mid length headers or manifolds?



5. I want to keep from moving my transmission at all. Which mounts will put my motor in the stock location? My understanding is the Dingo Sliders position the engine 1/4" higher than stock, Edelbrock's move the engine 3/8" forward from stock and the BRP mounts require you to drill holes in the frame. By stock location, I assume these manufacturers are talking about the rear mounting face of the block right? I mean what else can they use for reference?

6. Am I required to run a smaller alternator than comes with the Corvette accessory drive kit to avoid hitting the inner tie rod linkage? I'm already planning on a Kwik A/C bracket as I have a Vintage Air System in it already.

7. I'm planning on using AutoKraft oil pan but have heard that combination with a 4L60E and headers makes the starter virtually impossible to get at due to the pan's kick outs at the bottom. Any other options I should be looking at?

Thanks and I'll be sure to post plenty of pics of the build once we get going.

-Colin

[kochevy67]

well I can tell you this, I have a LS2 in my 67 Chevelle which is essentially the same car. I used 68-72 SBC frame mounts along with similar mounts which sort of mimic BRP mounts and yes I had to drill my frame after I welded up the existing holes, I also used a Billet Specialties Tru-Trac drive system due to the fact that the alternator would hit the tie rods, even though I have a rack in my car. I have Edelbrock headers and they fir well except for the one tube on the driver's side had to be massaged.

I used a LH8 Oil pan and it bolts right up with no problems. The starter is accessible but you do have to unbolt the header to drop it.

The trans crossmember had to be moved but my car is a convertible so the crossmember is different from a hardtop. I used a Rick's Hot Rod tank with a in the tank pump along with a Corvette filter which has a return line attached to it. As for the wiring I used the stock harness but I would definitely go with a Speartech Harness if I had to do it over again. I had John from Speartech make a DBW harness for me and it fits like a glove.

I hope this helps if not drop me a pm and I can help you if I am able to do so.

[rockytopper]

You should have no issues using the stock tank without a evap system. I have had no issues with the ls1 I'm running with with the same setup as you have out lined. Be aware also some of the oil pans have clearance isuues with the tie rod ends. I run the modified f-body pan from s&p which has notches in the front corners to clear the tie rods and they barely clear in my case. It all depends on your motor mounts etc.. The f-body manifolds work with your A-body if you donot want to run headers.

[neki67]

W.r.t. #2:
Speartech can make the harness exactly to your liking/customize it. They are using regular GM ECM's and it is up to you whether you go DBW or cable operated throttle. So yes, you can tune them (yourself) with e.g. EFI-live or HP-tuners.

The GMPP kit on the other hand is very complete and very professional but you can't say; 'hey would you like to make the wiring towards the ECM longer so I can (e.g.) mount the ECM in the trunk'. GMPP is using the E67 ECM which is the fastest GM ECM around and also totally tuneable with the aforementioned programs but can only be used in combination with DBW.

W.r.t. #5:
Hooker mounts will mount the engine in the same spot as the 400 you have in now so you don't have to move the trans.

[CFster]

W.r.t. #2:
Speartech can make the harness exactly to your liking/customize it. They are using regular GM ECM's and it is up to you whether you go DBW or cable operated throttle. So yes, you can tune them (yourself) with e.g. EFI-live or HP-tuners.

The GMPP kit on the other hand is very complete and very professional but you can't say; 'hey would you like to make the wiring towards the ECM longer so I can (e.g.) mount the ECM in the trunk'. GMPP is using the E67 ECM which is the fastest GM ECM around and also totally tuneable with the aforementioned programs but can only be used in combination with DBW.

W.r.t. #5:
Hooker mounts will mount the engine in the same spot as the 400 you have in now so you don't have to move the trans.

So, for $600 more I can specify harness length? Are there anymore reasons it's that much more expensive?

Just to confirm, they've cracked the ECM on the LS3 harness for tuning?

[neki67]

So, for $600 more I can specify harness length? Are there anymore reasons it's that much more expensive?

I don't know if the Speartech harness is that much more than the GMPP but I can tell you that you won't be disappointed by all the GMPP features. Like I said; only drawback (if/when you consider it a drawback at all) is you can only go DBW.

Just to confirm, they've cracked the ECM on the LS3 harness for tuning?

Yes, there's no problem tuning/recalibrating/etc. that ECM. I am more or less a novice when it comes to tuning/programming but have managed to swap/recalibrate/change the tune w/o any problem. I know for a fact; both EFI-live and HP tuners support the GMPP E67 ECM's that come with the GMPP LS harness/ECM kits.

[kochevy67]

I will say one thing John at Speartech is the best, I would use his harness. My question to you is if you use a GM harness who are you going to call if you have questions. Plus you can send him the ECM to put a tune in it for you.

[CFster]

Getting ready to pull the trigger on this project:

I have a 4L60E with a non removable bell housing. It's an earlier style, so it will only bolt up with five bolts instead of six. I hope that will be sufficient.

Can anybody verify my part numbers for the flexplate and spacer that I need?

12602448 - Flexplate
12563532 - Spacer

And here's my parts list:

19244097 - LS3 Crate Engine (btw, the GMPP catalog says this engine comes installed with a 2009 throttle body and I should use a 2008 throttle body if I'm using the GM harness, what's up with that?)
19155067 - Corvette Accessory Kit (Pace makes their own kit with is basically the same kit minus the compressor and brackets for $120 less - I'll have to investigate)
K10143 - Kwik Sanden Compressor Mount (up high) for my existing Vintage Air kit.
12635649 - Damper
AutoKraft - Oil Pan
Edelbrock - Mounts
SpearTech - Manual Transmission Harness Kit with ECU
SpearTech - O2 and MAF sensors
Street & Performance - Shorty Headers
Walbro External Pump 255lph
Filter/Regulator NAPA 373 (Corvette style)

As mentioned above, I'm already running a 4L60E with a Compushift controller. I've decided to keep that controller and go with a manual harness - one reason being I'd like to install a Shrifter and it requires the Compushift.

I've also been running a Griffin radiator with a big Spal puller fan. I hope that will be sufficient.

The rest of the parts will be had during the install - lines, fittings, ductwork etc.

[67 goat]

CFster,

I'm very excited about your project. I have a '67 GTO as well and am planning an LS motor swap in the next year. Not sure exactly what I'll use yet, probably whatever I can find used for a good deal, but preferably an LS2, LS3, maybe LQ4/9. I'm currently running a TKO-600 trans which I plan on keeping.

I'm looking forward for your project to start. Keep us posted as best you can!

Oh, and where are you located?

-Jeff

[Nicks67GTO]

Gentlemen. I too have a 67' GTO. I'm going to stay with poncho power for the time being. What exactly are you guys running for engines right now and are you willing to sell them? PM me with details. Thanks!

[CFster]

Motor came in last week.

Actually all I'm waiting on is the harness/ecu, headers and gas tank (decided to go with a tank with internal pump).

[CFster]

CFster,

I'm very excited about your project. I have a '67 GTO as well and am planning an LS motor swap in the next year. Not sure exactly what I'll use yet, probably whatever I can find used for a good deal, but preferably an LS2, LS3, maybe LQ4/9. I'm currently running a TKO-600 trans which I plan on keeping.

I'm looking forward for your project to start. Keep us posted as best you can!

Oh, and where are you located?

-Jeff

Jeff, I currently have a TKO-600 in a '64 Dodge, with a hydraulic clutch. Nice trans. I'm in CT.

Gentlemen. I too have a 67' GTO. I'm going to stay with poncho power for the time being. What exactly are you guys running for engines right now and are you willing to sell them? PM me with details. Thanks!

Novaguy73, we have the stock 400 in it now (original). It's smoking, so it needs a rebuild. We'll probably just put it in a crate for a while. We're going to hold onto it.

[Nicks67GTO]

Hey as you go along are you planning to keep a detailed sheet on parts, part numbers and expenses to get this swap done? I think it would be interesting to see a real world expense with this swap.

[CFster]

Yeah, we are a repair shop (of sorts), so everything is going in a work order.

[cspecken]

Curious where you purchased the motor and cost?

[CFster]

Got the accessories on. Still waiting for the right A/C pulley...

[CFster]

Does anybody know where I can get small block chevy engine frame mounts for a '67?

[phasemaster1]

Came across these http://carshop.carshopinc.com/produc...110328/CSP2380

[CFster]

Those look strange. They don't look like factory small block frame perches. They look like they set back the mounts or something.

[phasemaster1]

I think they actually set forward. Look at b-man's post #163 where he used chevy mounts and had to drill new holes in frame cross member.

https://www.pro-touring.com/forum/sh...ng-list./page9