if i were to put an LT1 in an originally equipped 3rd gen TPI car, would it need a new computer and harness, or would the one already in the car work? i know it's a tough one but i'm trying to weigh my engine options here....thanks guys!

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88 Trans Am, 5.0L TPI, flowmaster cat back, high flow cat, WS-6 performance suspension, black w/ t-tops, automatic transmission....soon to be armed w/ a 5.7 TPI

 

a stock LT1 manifold wont just bolt up to a TPI car. your gonna have to modify the hell out of it to make it work on your engine. not for the novice at all. you have to drill a distributor hole (needs to be exact), drill new bolt holes, and drill and tap coolant passages in the front of the manifold with heater hose adapters. someone on this site has a listing of what all has to be done to do this. but the ecm will work.

 

If you are talking about changing in the entire engine then you are going to need the computer and wiring harness. It is not an easy swap but not impossible. Do a search for "lt1 swap"

 

I'm going to go with no on this one. Reason being:

#1. After '93, the LT-1's were sequential fire. That means that the ECM reqiures a signal from a crank position sensor. Your stock computer, as it stands, has no idea what a crank position sensor is.

#2. GM used E-prom computers in 1992,1993 lt1's. As far as you being able to use your stock computer, no. These are the part numbers for the ECM's:

F,Y 1985 1226870 5.0L/5.7L
F,Y 1986-1989 1227165 5.0L/5.7L
F 1990-1992 1227730 5.0L/5.7L
Y 1990-1991 1227727 5.7L
Y 1992 16159278 5.7L LT1
F 1993 16159278 5.7L LT1

Whether the connections are the same, and you can burn a chip to make them work together, I don't really know, but I bet it would be cheaper just to buy the stock computer

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355 c.i.
Dart 180 Heads
Lunati 224/224 cam
Harland Sharp 1.5 rockers
Performer RPM Manifold
Holley 600 cfm double pumper
Hooker Super Competition Headers
Flowmaster Exhaust
Competition Engineering Sub-frame connectors
Super T-10
GM posi 3.42 rear
Hurst Roll Control
13.9@102

 

Unless you replace the intake with one that has a distributor hole (or mod one like someone on the TPI board has done) and run a standard distributor, you'll need the LT1 computer and harness - the LT1 uses the "opti-spark" distributor which is quite a bit different from a standard distributor.

 

oops, my fault, i skimmed over it fast and thought it said manifold not engine. the engine wiring harness from an L98 and LT1 is completely different. so are the ecms.

 

i had asked this question a while back.here are my thoughts.if you were to change the knock sensor to a 3rd gen one use the 3rd gen tb and all the sensors(coolant temp. sensor for the ecm,maf,knock,tps,iat,etc. as long as the sensor relays to the ecm the same data the ecm wouldn't know what size or year engine it's running.keep in mind you will have to drill the intake for the small base distributor(remote coil) as well as splicing the new accesories harness into the 3rd gen's.with some prom work it should work.

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87 trans am,gm crate 350(4 bolt mains 10to1),L98 aluminum heads,LT4 hot cam,slp runners,slp 1 5/8 headers,3in.y-pipe,edelbrock base,hi flo cat,air foil,afpr,as&m ported plenum,gutted airbox,t-5 tranny w/centerforce clutch and a 3.27 9bolt(11.9in. brakes),ed wright's fastchip,relocated iat sensor,160 fan switch&t-stat,tb bypass,accel supercoil,cap& rotor,slp 3in. catbcak,a/c delete.

SHE IS GONE BUT I KNOW THE GUY WILL GIVE HER A GOOD HOME.

best e/t:
3653lbs./full tank+ driver.
14.10@96.53mph 2.01 60'

 

Tell ya what, try it and let us know how it goes. Especially when you get to the distributor...can't wait to hear how you get the OptiSpark to work with a 3rd gen ECM.

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1982 Z-28

See http://www.mycar.net/mafb/registry/detail.cfm?id=276 for details