LSed LT1 or ZZ430 TPI?

stuckincincy

Apprentice
Sep 26, 2011
71
51
18
Greater Cincinnati area
Hi all,
Looking for opinions on what to do with my 86 Monte Carlo SS. It currently has a 95 LT1 with a 4L60E. I'm not happy with the lack of diagnostic and tuning capability with the current computer and the inherent opti-spark problems (been stranded on the side off the road in two different cars because of dead opti's), I've pretty much stopped driving it because of ignition knock under acceleration. I have a low mileage 350 cloned to ZZ430 specs with a TPI induction and the original TH200-4R from the SS sitting in the garage. I am planning to convert to an LS based computer setup with whichever way I go, but can't decide what engine and trans combo to go with. I can update the current engine harness to add the coils and crank signals using an LS computer. Here's the 3 options I'm considering:
1. Keep the current LT1/4L60E and just update the electronics using a torqhead signal kit.
Pros: Shortest down time, don't have to redo the A/C, P/S, fuel lines or cruise control setup.
Cons: Cam and crank signal kit costs about 2X what the GEN 1 parts would run, ugly accessory drive all mounted on passenger side, servicing the P/S pump and A/C compressor is a huge pain,
very few options and fairly expensive to change the accessories
2. Use the TPI engine with the 4L60E
Pros: Lowest cost, should be worth over 400/LB & HP with the right tuning
Cons: longer downtime, would have to redo A/C, P/S, and fuel feed.
3. Swap in the TPI and TH200-4R
Pros: similar to option 2
Cons: same as option 2 plus highest overall cost since the trans would need to be rebuilt, would need to figure out a VSS signal for the ECM and cruise control.
Let me what you think and if I've missed any pros or cons.

TIA,
Craig
 

Built6spdMCSS

Geezer
Jun 15, 2012
5,804
9,715
113
Florida Beach
There are a couple kits out there to convert a Gen II LT1 over, LTCC was one of them and I don't remember the second one. I've tuned a LS PCM ran LT1 and it responded quite well.
 

Supercharged111

Comic Book Super Hero
Oct 25, 2019
4,934
7,716
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Colorado Springs, CO
I want to convert the LT1 in my Camaro over to a 411 PCM. I've pre-emptively added a 4X reluctor and OBDII timing cover. I won't be adding a cam sensor. The PCM will batch fire the injectors this way. As an experiment I unplugged the cam sensor on my truck and it ran exactly the same. The opti will only exist as a cap and rotor and it'll be the most dirt cheap way to get that level of tunability and diagnosis ability.
 

stuckincincy

Apprentice
Sep 26, 2011
71
51
18
Greater Cincinnati area
I looked at Bailey and Delteq years ago when I started the swap, I know Delteq had shut down and thought Bailey had too. I want to use the 411 pcm because I can't find anyone locally to tune it and I can't pull any trouble codes with my current 95 LT1 pcm. That's why I'm looking at torqhead for the LT1 or EFI connection 24X for the tuned port.
 
Last edited:

Supercharged111

Comic Book Super Hero
Oct 25, 2019
4,934
7,716
113
Colorado Springs, CO
I looked at Bailey and Delteq years ago when I started the swap, I know Delteq had shut down and thought Bailey had too. I want to use the 411 pcm because I can't pull any trouble codes with my current 95 LT1 pcm. That's why I'm looking at torqhead for the LT1 or EFI connection 24X for the tuned port.

If you want 24x either of those options are good. If you want a 411 on the cheap, you can do what I mentioned above.
 

Built6spdMCSS

Geezer
Jun 15, 2012
5,804
9,715
113
Florida Beach
Yea I've been trying to find what I mentioned above, fired this in google as a start.


What I've seen is where the OPTI is taken out, that is the Cam Sensor, and LS Coils are ran. That I think is the LTCC Kit, it was 10+ years ago.
 

Supercharged111

Comic Book Super Hero
Oct 25, 2019
4,934
7,716
113
Colorado Springs, CO
Yea I've been trying to find what I mentioned above, fired this in google as a start.


What I've seen is where the OPTI is taken out, that is the Cam Sensor, and LS Coils are ran. That I think is the LTCC Kit, it was 10+ years ago.

That's how it's done with if you want 24x and sequential EFI. Are you ready to open your wallet that far? If you want to be cheap and resourceful, there is another way. Just not sure what your goals are with this. Mine is to not have the opti as a liability and have all the goodness the 411 offers for as dirt cheap as possible. The TPI would have its cam sensor jammed down the distributor hole.
 

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