2005 Pontiac Grand Prix GXP LS4 DoD 4T65E TAPShift powertrain swap into a Pontiac Fiero



Cooling system hookup (LS4 engine to Fiero). Used two molded heater hoses: AutoZone p/n's L-4103 and L-4447. These hoses came longer than needed but had the bends molded into them that were needed; so just cut them to fit. The main coolant feed and return were a little more complicated...

Basically what you will need to do is use the stock Fiero 2.8 coolant crossover pipe that connects the engine to the left side coolant tube. What you will need to do is cut off the 90 deg bend about 2 inches from where the mounting bracket is welded to it so you have just the 90 deg bend and nothing else. Make sure the end you cut is cleaned of sharp edges because a hose will need to be connected to it. Then you will need a GATES brand radiator hose p/n 21758 and cut off the 90 deg section that has the flared end; this flared end will connect to the t-stat housing (inlet) and the other end will connect to the 90 deg portion of the crossover pipe you just cut off. Then all you will need is another 90 deg section of radiator hose to connect the 90 deg section of pipe to the right side coolant tube coming from the radiator as shown in the pictures below...


That takes care of the right side coolant tube hookup to the LS4's coolant inlet (t-stat housing). Now what's left is connecting the coolant outlet to the left side coolant tube in the Fiero. What you will need to do is use the remaining section of Fiero crossover coolant pipe you cut the 90deg bend off of and cut about another 3" or so of tubing off the end you cut on previously. The goal is to remove the section with the welded on bracket so you have a clean surface to clamp a hose onto. I found the perfect radiator hose for this application, it's for a 97 Chevy Pickup C1500 4.3L V6; AutoZone p/n: XL-183. Once you get this hose you are going to cut off about 3" from each end. Then you are going to cut it into two pieces a couple of inches from the 45deg bend at the one end of the hose. If you are doing this swap for yourself you might want to mock the pieces up on the engine in the car before you cut the hose to make sure your fitment is right. Once done, you should have something that looks like this:


I feel it is necessary to support the metal section of the coolant crossover tube to the cradle or other surface to help keep it from swinging around while the car is driven. I used the remaining bracket on the coolant tube and fashioned a strip of stainless steel that allowed me to bolt the coolant tube to the trans mount bracket; which you can kind of see in one of the above pics. The left over piece you cut off of the XL-183 hose can be used to connect the coolant crossover tube to the left side coolant tube going up to the radiator.


Air induction system and air filter:


Used K&N filter p/n: RU3130 and part of some GM air induction tube p/n: 25176891 as well as the original MAF sensor from the LS4 and the air induction piece that connected it to the throttle body.

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