85 Trans Am w/carb, Convert to TBI?

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Oct 28, 2007 | 08:26 PM
  #1  
I have an 85 Trans am w/ an LG4 305 (4 bbl). Also have an 89 Camaro with a 305 TBI (PO claims its a swapped in 350, but i have not yet verified it , probably isn't however). Seems like everyone claims their Camaro is either a HO or a 350 and few really are. The T/A motor runs poorly and has blowby, so I am entertaining a plan to swap the Camaro TBI motor over. I prefer TBI to a carburetor for drivability anyway.

I have a few questions 1) Are the fuel tanks in these two cars the same? I will need to use the sending unit, pump and fuel lines from the 89 car, but not sure if it will drop into the 85 tank 2) I know I will need to use the engine harness, ECM, and fuel pump wiring from the Camaro , but are there any other wiring issues (specifically under the dashboard) to be concerned with? 3)Does the 85 TA have a VSS? If not will the 89 ECM function w/out it? I have several GM factory service manuals for similar vehicles to help sort out the wiring. I plan to get one for the T/A as well.

Since I have a complete running donor vehicle, I figure this swap is very do-able.. just looking for a little guidance from those that have done it already. Thanks
Jim
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Oct 29, 2007 | 08:01 AM
  #2  
Re: 85 Trans Am w/carb, Convert to TBI?
The RS has the L03 in it. It was rated at 170 HP. No HO, but more then your current LG4.

I think the sending unit and pump will fit the 85 tank, but with both tanks outside the car, you can always just swap the camaro tank in, unless it was a rear-ender. I think the biggest differences through the years was the ammount of baffling provided. I cant see any huge issues with the wiring since you have a complete doner. As far as the VSS goes, I believe that both the older CC carb cars and RS' up to 89 had the cable driven speedo/VSS, so that part should be a direct swap. 90+ had the different dash, electronic speedo, etc.
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Oct 29, 2007 | 04:57 PM
  #3  
Re: 85 Trans Am w/carb, Convert to TBI?
Thanks for your response. Sounds pretty straightforward. Only problem is dring the swap I will have 2 cars that are immobile. I only asked about the fuel tanks because the T/A tank looks alot better (lif ein the rust belt is tough on gas tanks/lines/floors etc)
Jim
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