does anyone know of someone who's done this? basically, if you were looking to use the factory LT1 computer and factory AUTO tranny, what would be involved in making a regular SBC/distributor work in this environment? i've got a buddy that wants to do this but he's thinking about trying to make an optispark work on an SBC (has anyone done that?)... since the opti isn't the world's greatest ignition i'm trying to talk him out of that... any thoughts/links/etc?

thanks!

 

I iwsh i could say yes but teh LT1 PCM would need a completely different signal thnan the dist or any GM dist can provide..You may be able to run a vortech truck dist..I havent pulled one apart but it may use high and low res signals..

 

IMO you would have much better luck running one of the late 3rd gen ECM's since they were designed to operate with a normal distributor vs an opti. The 90-92 SD ECM's are considered the best of them BTW. However if you went that route you would need something to run the 4L60E.

Not saying you couldn't get the 94 PCM to work but I think its more trouble than its worth.

 

You might try using a Vortec truck distributer. Not sure if it will provide all the signals. I was doing an intake on one and took a good look at it. It uses a simular type of trigger as the LT1

 

Why not just run a 700R then?

All my "FI SBC in a 4th gen" plans have always included FAST & a coil-pack setup. I wouldn't run a computer that's limited to 7K rpms, and a distributor that has a 60K mile life expectancy.

 

The Vortec truck distributor only has one output that roughly emulates the Opti low-res outputs.

If you're hellbent on running an LT1 PCM on a GenI SBC, it might be best to look at adapting the Opti internals to a standard distributor.

 

The opti internals will fit inside a small cap distributor... once you rig that the rest should be easy.

 

#1 the wheel is too big unless you get it into an HEI #2 you will never get the ring in the perfect location to provide the presise timing required to have the low and high res signals at the proper point in time..

 

Oh well, I guess that I don't know what I'm talking about... to bad I can't find the pics of it right now, oh, and it runs also...

 

I am interested in seeing the out come of this, if you can get something to work...

 

Why bother? Your talking about putting gen1 non roller block into a 4th gen???

use a l98 block and pcm if your just after the looks but want simplicty I guess?

 

I’m not sure why you’re differentiating a Gen I roller vs non roller block.

The biggest reason that I can see doing it in an originally LT1 car is if you really need a serious setup, to use one of the beefier aftermarket blocks which are just not available as LT1’s, but I’m not sure why you would run an LT1 ECM.

The reason to do it in an older chassis ranges from the LT1 PCM is more flexible then the more traditional ECM’s that GM used, or you’ve got an LT1 in an older chassis and want to get rid of the opti (don’t trust it, need more room up front…), and then you just drill the back of the manifold for the distributor, make a spacer and hold down and remove the oil pump drive in the back of the block, and you’ve got a ‘normal’ distributor in an LT1.

 

I've actually been trying to find an answer to this question too. I know that the vortec truck distributors do send a dual phase signal to the ecm (high-res and low-res). They utilize a CKPS (crank position sensor) to do this; so if you wanted to use a vortec distributor, you'd have to use the matching CKPS. Then you'd run into the same question I desperately need an answer to: will an lt1 ecm recognize a vortec dual phase signal? If anyone on this board has access to that little nugget of information, please post it on this thread. I don't have the first clue where to get info on voltage, ohms, etc. for either the opti-spark or the vortec, or for ANY of the sensors I need info on, and i know a few fourth-gen owners who don't want to keep any part of the opti in their car if they don't have to. Somebody out there has got to have the numbers to let us know which GM part #'s can talk to an lt1's ecm (i emphasize that GM because I would much rather be able to go to any NAPA or GM dealership and get my parts NOW, than have to worry about which one of my custom and/or aftermarket parts will crap on me and put the car OOC for an extended period of time ).

 

This is interesting. I may have to look into this. Which year vortec truck distributor would be the best to look for?
Kory

 

One thing i am wondering:

Why not try to adapt an ls1 pcm? if you have a CKP, you could try to adapt the reluctor ring from the ckp to the one on the vortech trucks front cover.

The ls1 pcm only needs the ckp signal to correctly fire the injectors.. a simple camshaft sensor COULD be added and i know there is a thread here of someone that did design a camshaft position sensor out of an opti unit.

The other is.. why not use the front cover AND opti and lt1 camshaft on the sbc block and use the opti and oem pcm? Why use a distributor? run a LTCC and good to go...