First off, GOODMORNING!!!

Ah, had a lot of Monster already. As the title states I am trying to see what I can reuse off of my old motor. The car is a 92 RS with the TBI 305 and T-5 combo. The motor going in is an L69 from a 87 Monte Carlo SS. I already have a Edelbrock Performer Intake and Edelbrock Performer series 650 cfm w/ electric choke from a previous el camino build that never started, all still new in the box, along with some other goodies. Can the alternator and power steering pump still be utilized? The Harmonic balancer? little things like that. The motor is going to be put in the machine shop for a good thorough cleaning and to be re-ringed, but it only had around 65,000 miles at the time it was pulled so the machine shop wants to just check all measurments and what not. My endstate is to go ahead and finish my wire tuck by the end of the weekend so if possible. AC, air pump stuff, egr, ect will all be deleted. It will be a track car only pretty much for local auto-x events and whatnot, so emissions is not an issue, and it will be registered in SC as well, so no inspection. As a disclaimer, I chose to not go the 350 route due to a free motor falling in my lap with low miles, I also want to keep the T-5 for now due to budget, and just because I want to. I know this is kind of broad, but I am deffinently looking for insight and not critisism. Thank you for your time!

 

IIRC the l69 was an option on the Z28s. AFAIK it should be a straight swap. Youll need to either modify the fuel pick up for carb or run a regulator to lower the pressure at the line. We are in the planning stages now of a 283 sbc into a 92 RS....so only reason I know some of this is by finding out what wont fit on our swap! Lol.

BTW. Im 45 minutes from you, near Morehead City and the beach.....so ever need nething hit me up!

 

Basically what's on the front and what's on the back of the LO3. The accessories, damper, flywheel no problem. And a few side things like the starter, oil pressure sender, and temp gauge sender.

Hopefully none of the TBI exhaust is going back on.

 

Hey Gents, thank you both for the resoponses. Thats a negative on the exhaust as a whole. Im currently looking around for a good shorty and y-pipe combo, lots have caught my eye but just looking at the moment. Car already has a full 3" into dual tips with a glass pack, sounded good, but myself and a friend are looking at fabbing another exhaust utilizing the SLP LM2 resonator, single all the way out the back under the axle sense ground clearence is not that big of an issue for the application. At the moment the wiring is kicking my tail. Im trying to figure out what I can keep and what I can get rid of and I can not find a thread that shows details on this, so i'm kind of winging it at the moment. I have seen the tbi swap threads for the carb conversion and I was tracking on the fuel pick up. Im debating the swap to a mech fuel pump, but everyone seems to be more for the electric with a regulator, so why go against the crowd! Ha. So I will be doing that mod bonylad. As well, dude we should deffinently do a cruise day soon, as soon as we get our heaps running! :-)

 

The ECM harness won't be needed. That the one that goes to the passenger fenderwell. It can be removed without cutting anything out.

You will still need the VSS that comes from the transmission. I'm not completely familiar with that harness's routing, it may be part of the ECM harness (someone with a TBI T5 can chime in here).

Keeping the ECM itself in place will allow it to keep powering the in-tank electric pump, if you stick with that.

 

57, please forgive me for this but im coming inside and checking this thread as I take breaks, what is the VSS and what would you recomend as the optimal setup to fuel the motor? Stay electric? Go with the mechanical setup? My dad is saying go with the mechanical and call it a day but your input on this would be awesome. I'll be back on shortly, I just finished getting the passenger side harness all the way out to the point its going into the fender. The motor will be most likely a stock bore, possibly .010 over, with a slightly larger cam. Exhaust will be as stated earlier.

 

Not directed at me, but....were running the mechanical pump on the 283 and moddin the pickup.

Lol. yeah we should do that. Thanks and lemme know if I can help.

 

VSS - Vehicle Speed Sensor. In a '92, it is in the transmission tailshaft housing. There is no speedometer cable, so the speedometer is electronic and runs off of the signal from the VSS.

Fuel - 3rd gens are not nice to the fuel as it goes from the tank to the engine. Bombard it with heat. A mechanical fuel pump tries to suck fuel through that juggernaut, and sucking lowers the pressure in the line. Combine heat with low pressure and gasoline changes phase from liquid to vapor. Carburetors don't run well on vapor. This is a condition called "vapor lock".

For their carb'd 3rd gens, the factory used a mechanical pump with a return line. That helps keep the fuel moving in the supply line so it doesn't pick up as much heat on its journey, and keeps a cooler supply from the tank in the line. That wasn't totally effective, though, so the L69 cars (most of them, anyway), and all of the '87 model carb'd cars got an electric in-tank fuel pump in addition to the mechanical with return. This is an improvement in two ways: 1) Pumps are good at pushing a liquid, especially if the pump is immersed in fuel; and 2) raises the pressure in the supply line to reduce the likelihood of vapor lock.

That was a long explanation to lead into my answer to your question - I'd keep the in-tank electric pump operating. If you use a mechanical pump, it had better be a return type like the factory used. You can use both, which isn't a bad idea (but use a return type mechanical pump). There are a couple of considerations here: The factory V8 mechanical pump fuel lines crossed from the driver side where they come up the driveshaft tunnel to the passenger side where the mechanical pump is, over the transmission - great way to pick up more heat. The EFI fuel lines go into the engine compartment up the driver side frame rail. If you use a mechanical pump, you're going to have to add line to cross over to the passenger side. If you do that, I'd recommend running the lines in front of the crossmember - much cooler location than the routing the factory used. If you just use the in-tank electric pump with a return-style regulator (if you use the in-tank pump, you MUST use a return - the pump relies on a constant flow of fuel to keep it cool), you can just connect the reg to the EFI lines, then run a line from the reg to the carb.

 

Ah, now I feel dumb because I sat and thought about it and put 2 and 2 together and got 4. VSS, ha!

I have pretty much got the motor torn apart now, and I'm now trying to weigh out whether I should do any head work or not. I am looking for just a reliable setup with decent power but nothing to amazing. Hopefully high 200's in the HP department. Any cam suggestions out of curiosity guys? I have been looking at the summit cam kit with # SUM-K1104 duration @ .050" is 224/224 and the lift is @ 465 for int and exh. To much cam on a stock rebuild? Opinions?

 

Decided on not getting the block machined. Low miles, cylinders look good, so I am just going to get the heads cleaned and assmebled by the machine shop. Just need to decide on the cam still, but I am also looking at the xe262, its aggressive and works with my RPM range. As well, with running the T-5 and no computer to deal with, it fits my application. I look forward to some insight guys!

 

With losing the ecm and what not, can anybody tell me what functions or issues I will run into? Things like the VATS system are coming to mind... but if I am just losing the passenger side harness, can I keep the ECM? This part of the swap is worrying me and I want to do whats right. A possible thread/link that anyone knows of would be great, because I can not find crap.

 

https://www.thirdgen.org/vats_passkey_system


Should help you out the VATS thing. AFAIK....your not really losing anything related to the operation of thew vehicle...other than the motor. If I am correct the car was made before a module did this and that and so on.....they were pretty much all independent modules. You wont need the ecm and harness.

 

Bringing this back...

Decided to go the route of the in-tank with a regulator due to ease and 57's recomendation, but my question is this. Now that the harness to the ecm is removed...how does the fuel pump work if the engine harness is gone? Obviously a noob question but I can not figure out how this will work. What needs to stay in place so that I can get rid of the wiring but keep the pump? Just curious.

 

That help you any?

 

http://www.austinthirdgen.org/index.php?pid=41

Nice VATS article too.

 

Honestly ... no. But my neighbor who is helping me does so im good. As soon as I see him guys then ill find out.

 

Vats I've got though.

 

Another question, related to the fuel pump. Using the wiring diagram...what parts need to be kept? I.E, what plugs exactly, a possible write up on this?

 

as long as you keep the 3 prong oil pressure sender, the fuel pump will work off it. once the sender sees oil pressure (ie you cranking the engine over) itll kick the fuel pump on and keep it running as long as the pressure is present.

as far as the VSS wiring (i dunno if its been answered already) it isnt mixed in with the ECU wiring. it runs from the trans into the cab through main harness on the driverside, along with the backup light wiring.

 

So all i need to do is make sure to keep the oil pressure plug and ecu, just keep that wire and the ecu?

 

you dont need the ecu at all. the 3 prong oil pressure is seperate from the ecu. it just has a juntion that ties the ecu into fuel pump wiring to supply power. the oil pressure switch is a fail safe incase something happens to the ecu while driving to keep the fuel pump running. by removing the ecu, youre turning it from a fail safe, to the primary way to fuel pump runs.

 

Where on the harness is this plug? Neighbor deployed and now im flying solo on this. Fml

 

Anything?

 

The plug for the oil sensor? Its pluged into the oil sensor either on the china wall of the block right around the distributor, or right aboove the oil filter.