Grand prix 3800 engine swap

Asked by Jan 18, 2017 at 12:06 AM about the 1988 Pontiac Fiero Formula

Question type: Car Customization

Swapping a 3800 engine into my fiero.. 3800   
engine was mounted whit a automatic
transmission,  I am using my  5 Speed
Manual Transmission.. do I need to make
changes to the engine to make it work??? I
know it mounts perfect into the
transmission.. does it matter if the engine
came from a automatic transmission?????

2 Answers


look at spending upwards round 4-5 thousand in parts etc to get er done,double that if you dont have a decent motor for the swap or the skills nessasary to do the install. Just price out the good flywheel that youll need to convert over to your tired 5 speed and youll get the drift as to what parts cost doing this swap. Even guys who have done this swap say "rebuild the 3800 prior to the swap" rather than when it starts to act up. For sure do a brake upgrade. If you insist on doing this swap half assed (by yourself) you will run into problems down the road. Do lots and lots of research,know what parts youll need, buy a few at a time over time and plan for the day youll be ready to do the swap,Do things right and dont rush,youll enjoy the end product that much more. Leave the rebuild to the pros. They know these engines and will give you a guarentee on their work. Peace of mind is a big thing when your about to embark on a trip clear across the country. No little surprizes along the way. That alone ought to be worth the 2 or possably 3 thou, you may have to pay a pro to inspect and rebuild what you already have and install that flywheel and the starter (it goes on the other side of the block) and and while he is doing all that you could be pulling your tired 2.5 or is it a 2.8? Eather or, get it and the tranny out, clean up that empty space where it was,reinsulate,wash everything down,and clean up and paint your frame so that your 3800 will have a nice home Dont forget to buy a harness for the 3800,Im assuming it came with a harness? Some places require that you provide the Fiero harness as well as the one for the 3800 Talk to some and then make your choice of who your going to have make that all important piece. look at spending 3-5 hundred on this one item. See, while your doing all that running around and chasing down parts buddy is doing the engine and the electrical guy is building your harness,both pros will give you a completion date and if you planned well,both will be ready at about the same time,meaning time for you to get er done

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