LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

what all needs to be done to run a top mount distributor?

Old Sep 24, 2010 | 05:42 PM
  #1  
LSWHO's Avatar
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what all needs to be done to run a top mount distributor?

...and keep the stock pcm?
Old Sep 24, 2010 | 10:01 PM
  #2  
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Obviously, you will need an intake with provisions for a rear distributor, but need more info on what else you are doing. You won't be able to keep the stock fuel injection without the opti.
Old Sep 24, 2010 | 11:56 PM
  #3  
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If your looking to toss the opti I would just go with a ls1 type set up. Check out http://www.eficonnection.com/eficonnection/24x.aspx
Old Sep 25, 2010 | 01:54 PM
  #4  
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i think you could use a 411 pcm which has the 18436572 firing order, the reluctor ring and timing cover from a 96-97 lt1 car, or the reluctor from a l31 vortec engine and the 96-97 LT timing cover that has the crank sensor provision, and a vortec reluctor, the 96-97 LT1 reluctor might actually work...

if your serious about it it would take some wiring, or find a donor vehicle, i think the 2000-2001 express van is the best thing to use as a platform because it has a vortec engine in it and uses the 18436572 firing order, yet it uses a LS based pcm..

finding the van would probably be kind of difficult but not impossible if you know some large salvage yards, the van is a fleet utility model.. also any LS based pcm can be flashed to the 411 pcm, the reluctor and crank sensor can be bought from advanced or autozone, or find any old vortec engine at a junkyard and get the parts there.. i'm pretty sure the transmission functions can also be disabled if your using a non-electronic controlled transmission, i'm using a 700r4 in my 27 rpu, so i wont need trans functions, the vss would be one of the dakota digital boxes that connect to the speedometer provision on the transmission...

this setup is what everyone and their brother is using to convert old gen1 sbc's and bigblocks to fuel injection...

all kinds of info on it on the internet about it, you need to hit up streetrod forums.. www.thirdgen.org (i think that was one source of info) i found alot of info on it, and also on hotrodders.net or com is another one... i found all this when i was looking for a good junkyard fuel injection setup for a gen1 sbc... actually after you get to reading about it, all the information from site to site matched up pretty close and was rather simple after i read up on it more and more...

theres really no need to buy an eficonnections setup i dont think.. unless i'm missing something.. all they have done is basicly took the outer part of a LS reluctor which is 24x and adapted it to work on an older engine, and with the correct pcm and reluctor you dont have to do this.. for instance the 411pcm and vortec reluctor which can be found at about every junkyard in north america..


i found a 99 truck, got the pcm, and coils from it.. i'm probably going to go back and get the injector harness, coil harness, and probably the injectors, and also the pcm plugs..I'll have to move the coils and injectors to the correct the firing order because the 99 firing order of 18726543 is different from the gen1 sbc and LT 18436572 firing order.. i'll then use an old vortec timing cover that will bolt up to a gen1 sbc, and also the old vortec 4x reluctor will work...
Old Sep 25, 2010 | 02:16 PM
  #5  
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heres a parts list i found on several sites for converting a gen1 sbc to fi

12200411 PCM (LS1, Truck, S-10, Blazer, Express, others)
Wiring Harness for 12200411 (must follow Vortec L31 schematics for the correct firing order)
Vortec 305/350 Distributor (has cam sensor in it)
Vortec 305/350 Harmonic Balancer (which is shorter by the thickness of the reluctor)
Vortec 305/350 Timing Cover (provision for crank position sensor)
Vortec Timing Reluctor Ring (goes behind timing cover)
Vortec Crank Position Sensor
Vortec Ignition Module
Vortec Coil
Knock Sensor (2001 Express Van w/ 5.7 engine)

not sure of the LT1 timing cover and the vortec timing cover, i think the bolt pattern is the same, just the LT1 cover has a hole in it for the distributor and the waterpump drive, which would need to be plugged....

the 2 things that make the LT1 bastard to any other gm fuel injection is the pcm and the optispark that contains both the crank and cam signal.. about every other gm fuel injection set up uses a seperate cam signal and crank signal, seperating the high voltage side for the ignition from the crank signal.


added this:
for an LT1 specific swap:
you'll need an intake with a distributor hole, alot of people use a victor jr fi intake, there is another intake thats about $100 cheaper its a professional products fuel injection intake, and you need the rails also... you'll also need an intake elbow to use your stock throttle body or a 4 hole throttle body.. also a hood to clear it all, a vortec distributor, split your opti harness, leave the low voltage side intact(for crank signal) the high votage side will connect to the vortec distributor,coil, and icm...

whats funny is do a search for a 93 truck distributor, and compare the cap to an optispark cap, also compare the coil and icm, they look near identical, almost bet theyre the same part numbers except the cap.. you could also have a distributor hole cut into a stock intake, but you'll have to know a machinist or someone that is familiar with doing it.. if i were building an engine and had it out of the car i wouldnt be scared to do it, actually would do it and not think twice..

Last edited by brucer; Sep 25, 2010 at 03:27 PM.
Old Sep 26, 2010 | 08:44 AM
  #6  
MichiganSkip's Avatar
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From: Three Oaks MI
ask this guy,
https://www.camaroz28.com/forums/sho...d.php?t=306241

do a search, it's been talked about years ago.

https://www.camaroz28.com/forums/sho...ht=distributor

Last edited by MichiganSkip; Sep 26, 2010 at 08:47 AM.
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