G.T. Fieros

I have been trying to decide between staying with a 3800SC and modifying it for my Formula or going with some thing else since the LS4 I was looking at ended up being no good.
I am considering a nice low mileage 3500 or a 3900 and using my F40 6 speed with it and see how that goes then maybe add in a nice turbo later on.
Also considering a nice eco tech and maybe a turbo one at that. Draw back to the eco tech is the cost of a good turbo engine.
I found a very nice low mileage 3900 that is out of a manual G6 making it a fairly easy job as I also can get the ECM and harness along with the engine. Plan would be to keep it fly by wire and make good use of the VVT.
So basically either a modified 3800SC using a 2003 SSEi engine I already have and instal the XP hot cam with its supporting parts and short stack inter cooler. or the 3900 and maybe a turbo later on or last choice the eco tech turbo.
Any and all opinions welcomed. Dan

as much as I like the 3x00 series motors, the 3800 will probably the motor to outlast in parts to come. 3900 was only made for a short time and not much aftermarket for it while the 3800 motor will have aftermarket parts for a while still.

Yes that is true, I am mostly only considering the 3900 due to its power being about the same as the 3800SC but using 87 octane fuel instead of a min 92 which costs a lot more. But the 3900 is a very tight fit in the Fiero and will be a lot of work getting the stock ECM to work just right.

3900 is also drive by wire, so if you want the VVT you need the keep the ECM & the funky gas pedal to go with it.

Yes did a 3900 auto swap last summer and kept the stock ECM and fly by wire throttle body but was not that impressed with it. I am wondering if maybe more tuning is needed or the addition of the BCM to make the VVT work properly. Mind you that was an 07 Van drive train and ECM where if i go with the F40 I will be using the G6 ECM which from what I have been able to find out is a more aggressive program power wise.
I know 3500 and 3900 engines can easily be found with low mileage for quite cheap where it is getting harder all the time to find good 3800SC engines that do not have at least 200 to 300 thousand km or more on them.
Main thing I am trying to avoid is the need for the high test fuel with the cost of gas these days but with a properly set up 3800SC Fiero you do get pretty good fuel mileage which helps off set it a bit.
Think we just need spring to finally arrive so I have to make a choice and get to work on the car. Dan

If fuel economy is a big concern, why not go with an Ecotec? Lots more room in the engine bay, great on gas, and lots of aftermarket support for more HP