Which P4 PCM should I use

[CDeeZ]

Okay after scrounging the salvage yard for the past few days I've managed to come up with four separate P4 PCMs

I have TWO 16197427 PCMs
ONE 16196395 PCM
ONE 16168625 PCM

Which one should I use? I'm getting really close to converting my 747 setup and I would like to know which PCM would be the best shot? I know these PCMs are all in the same family of P4's (at least I think), but is there one that I should use over the others???

[Six_Shooter]

Those are actually P66 PCMs (Some may call them "P6").

You won't see a functionality difference between them, that I have been able to find.

That being said, I would likely use the '7427, just because it's more common.

[dave w]

Either one will work. I think having an original V8 Memcal would be a good idea. I have a 93 K1500 I use to test PCM's with. I swap the Memcal with the correct tune for my K1500 and have tested 16196395, 16168625, 16197427, 16156390, and 16196396 PCM's without any issues.

dave w

[RobertISaar]

........................ hairsplitting mode engaged .........................

those are all P6. P66 = dual P6 processors. AFAIK, only the 94-95 LT1/L99, 93-95 3100/3.4RWD and 93-95 Northstar earn that title.

[EagleMark]

Has no one ever got a LT1 PCM to run a small cap EFI distributor or DIS yet? Maybe it's time for a HyBrid OptiSpark distributor on a SBC?

I must be bored to think up an idea like that again... sure would run good though!

[RobertISaar]

if you removed the dependancy of the 180X signal and the cam signal(assuming you don't want to simulate/integrate it) from the LT1 PCM, then i don't see why it couldn't be done with either the dizzy or the northstar DIS.

[jameslleary]

[EagleMark]

My bench...

[JeepsAndGuns]

I think this has come up before in other threads (using a LT1 ecm)
Is it like a super nice or extra good ecm or something? Why such a big desire to put it on a diffrent engine if its made for a specific ignition system thats not swap friendly?

[EagleMark]

It's an excellent PCM, underhood waterproof, flash through ALDL, Sequential. Drawbacks for using it on other then LT1 engines is cam sensor and the OptiSpark distributor which is mounted to camshaft behind waterpump. Other then that it looks like a TPI engine with a way better TPI.

[CDeeZ]

Those are actually P66 PCMs (Some may call them "P6").

You won't see a functionality difference between them, that I have been able to find.

That being said, I would likely use the '7427, just because it's more common.

7427 it is then!

Either one will work. I think having an original V8 Memcal would be a good idea. I have a 93 K1500 I use to test PCM's with. I swap the Memcal with the correct tune for my K1500 and have tested 16196395, 16168625, 16197427, 16156390, and 16196396 PCM's without any issues.

dave w

So you can swap memcals between V8s with similar equipment, but different PCMs, is that right?

........................ hairsplitting mode engaged .........................

those are all P6. P66 = dual P6 processors. AFAIK, only the 94-95 LT1/L99, 93-95 3100/3.4RWD and 93-95 Northstar earn that title.

LOL

Has no one ever got a LT1 PCM to run a small cap EFI distributor or DIS yet? Maybe it's time for a HyBrid OptiSpark distributor on a SBC?

I must be bored to think up an idea like that again... sure would run good though!

I'm not a fan of that optispark dizzy on the LT1 b/c it's expensive and if your water pimp goes south it usually takes the dizzy with it, but put that dizzy out of harms way, where a conventional dizzy goes and that would be cool.. Of course My ultimate plan someday is to go DIS.

My bench...

James, Mark, forgive my ignorance, but WHAT ARE THOSE?

I think this has come up before in other threads (using a LT1 ecm)
Is it like a super nice or extra good ecm or something? Why such a big desire to put it on a diffrent engine if its made for a specific ignition system thats not swap friendly?

It's an excellent PCM, underhood waterproof, flash through ALDL, Sequential. Drawbacks for using it on other then LT1 engines is cam sensor and the OptiSpark distributor which is mounted to camshaft behind waterpump. Other then that it looks like a TPI engine with a way better TPI.

Yeah, the 411 is a good PCM. I think it's a pretty common PCM used by the LSx swap guys. I think I'll run a 411 or similar whenever I get around to my 6.0 swap some day

[EagleMark]

Those are insides of OptiSpark distributors.

You and many people have fallen for internet rumors of them. They are by far the most excellent and advanced distributor ever made, there is nothing better until DIS or COP. Rumors rumors rumors.

Just because a couple people said there Opti was wasted when their waterpump leaked is BS. First the maintence on an OptiSpark distributor is to inspect distributor and replace cap and rotor at 100K. Try that with any other distributor? Mine had 125k on it and I ran the engine and ran a garden hose on it for 20 minutes without issue. If you have one that the Oring seal has gone bad, do maintenece, if your water pump leaks it's no harm to Opti unless Oring has failed, do maintenece!

[CDeeZ]

I hear what you're saying, with maintenance it shouldn't be an issue. I have no experience in LT1 stuff really, but I knew someone who had an LT1 Fbody and was pretty good about maintenance and upkeep of his car since he was a geahead, but somehow, he did end up losing an optispark b/c of a waterpump failure. But ah well

[dave w]

So you can swap memcals between V8s with similar equipment, but different PCMs, is that right?

What I've done is use the same V8 Memcal that was original to my 93 K1500 5.7 in the following PCM part #'s 16196395, 16168625, 16197427, 16156390, and 16196396 without any issues.


I've done several TBI PCM upgrades, any one of the following PCM's part numbers 16196395, 16168625, 16197427, 16156390, and 16196396 will work! I recommend purchasing a TBI PCM that has a V8 memcal if your conversion is for a V8.

dave w

[CDeeZ]

Ok I think I understand. All the PCMs I picked up were from V8 trucks, all 5.7Ls I believe, so I should have all V8 Memcals

Just fired my 427 for the first time, runs rough, going back outside with the laptop and an adx file to try to see whats up....