Georgia Fiero Club Forum

All Things Fiero => Tech Tips, Tech Questions => Topic started by: Cdepoy84 on February 22, 2021, 10:42:51 am

Title: What engines can fit in a 1984 fiero
Post by: Cdepoy84 on February 22, 2021, 10:42:51 am
What engines can fit in a 84 fiero. I'm looking at engine swapping my fiero but don't know what engines fit in my fiero. With little to no frame work done
Title: Re: What engines can fit in a 1984 fiero
Post by: TopNotch on February 22, 2021, 12:05:33 pm
This article (https://gafiero.akroncdnr.com/docs/84v6.pdf) explains how to put a V6 in an 84 Fiero.
Title: Re: What engines can fit in a 1984 fiero
Post by: Fierofool on February 22, 2021, 12:17:04 pm
Small block Chevys, Corvette, Northstar, 3400TDC, 3800 NA & SC, 4.9 Cadillac fit without sheetmetal mods.  Due to the 84 having a totally different electric harness than later years, engine upgrades are more difficult.
Title: Re: What engines can fit in a 1984 fiero
Post by: GTRS Fiero on February 22, 2021, 01:11:09 pm
Define fit.  Without mods?  With same transmission?  Without cutting the frame?
Title: Re: What engines can fit in a 1984 fiero
Post by: GTRS Fiero on February 22, 2021, 01:16:19 pm
Small block Chevys, Corvette, Northstar, 3400TDC, 3800 NA & SC, 4.9 Cadillac fit without sheetmetal mods.  Due to the 84 having a totally different electric harness than later years, engine upgrades are more difficult.

I believe the frame must be notched for the SBC swap.

I suspect for the Northstar and Corvette engines, also.

For the 3800SC, it depends on how the alternator is placed.

The 3400 DOHC, on the '84, maybe.  It is a tall engine, so the decklid could be an issue.
Title: Re: What engines can fit in a 1984 fiero
Post by: Fierofool on February 22, 2021, 02:13:09 pm
Swap to an 85-88 decklid.
Title: Re: What engines can fit in a 1984 fiero
Post by: pgackerman on February 22, 2021, 05:21:31 pm

Today's 4-bangers have more than double the power of your '84's 2.5L and come with a 5 or 6 speed manual, or at least a 4-speed auto.
Guessing their smaller size would allow them to fit easier than a V6.

They also get better mpg out of your sub-10 gallon tank; which might be a concern if your planning on driving further than local auto shows.
Title: Re: What engines can fit in a 1984 fiero
Post by: GTRS Fiero on February 22, 2021, 06:51:36 pm
All true; however, many of those engines will require a lot of electrical work.

A year ago, I did a lot of research on engines.  Not 4-cylinders, but 6- and 8- cylinders.  I published a bit of that, but still have more than 200 pages of notes.  The most important take-away was that it's all up to your builder.  Only your builder can answer these questions.  So, the Spring articles last year were limited to info about the engines themselves.
Title: Re: What engines can fit in a 1984 fiero
Post by: Raydar on February 22, 2021, 09:37:50 pm
The real issue is that the C500 connector is very close to where the left (aka "front") exhaust manifold wants to be. Right in the middle of the firewall.
85 and later cars extended that connector over to the area between the battery and the shock tower. Otherwise, any number of engines will fit without a great deal of difficulty. It really depends upon how much power you want.
One "neglected" swap possibility is the LE5 2.4 Ecotec. It was never available "boosted" in any GM car (Those were the 2.0s and 2.2s) but it made more power in NA form than any other Ecotec. (177 HP or so) "The rest of the story" is that it is the motivational force that drives the Polaris Slingshot.
In that application, a nice cottage industry of go-fast parts has evolved. Some of them are very likely adaptable to that engine, installed in a Fiero.
Title: Re: What engines can fit in a 1984 fiero
Post by: GTRS Fiero on February 24, 2021, 07:14:57 pm
What engines can fit in a 84 fiero. I'm looking at engine swapping my fiero but don't know what engines fit in my fiero. With little to no frame work done

Frame work?  That eliminates just about every V8.

Many engine swaps necessitate transmission swaps.  Certain transmissions require modifications to the engine cradle/subfeame.  If you add horsepower, you need to beef up certain things.

Who will be building this?