Fiero 3400 Airbox/ Stock Exhaust Question (Page 1/1)
Kyabbage NOV 22, 11:44 PM
Hi, I'm a new user to this forum, I've been using it for just under the past year for pretty much any technical problem I've had with my '85 SE notchie since I bought it around the same time.

I've recently started my first ever motor swap! A 3400 (LA1) into my fiero from an '03 Impala, and I've got it most of the way done from all the information up on here, but I still have some questions.

#1 Exhaust


The flange that came off the header originally was too long to clear the trunk, so I'm just wondering which kind of flange to order, I've got very limited options locally (small town stuff) so if anyone has a part number or something that would be wonderful!

#2 Intake

I want to try to adapt the tubing from the airbox (in my case I plan on trying to keep the fiero original) to the throttlebody. I still have my mass airflow sensor hooked up, so I'm a little stuck on how to do that.
Spoon NOV 25, 07:38 PM
You may want to find an exhaust shop that does custom bending.
Or plan "B": Trace out a pattern from the exhaust manifold flange and go to your parts store. Tell them to look thru their Walker catalog for a companion flange that matches your drawing. Thickness may vary,,,, thicker is usually better. Don't forget the flange bolts and gasket. While you're there pick up an appropriate length of that flexible exhaust tubing and fashion it in a shape to connect to your receiving pipe. This will be your pattern for the real pipe. Allow for a braided flex connector and maybe a Cat if required. Once you're satisfied with your results remove the assembly and take it to your exhaust bender and have them duplicate your project. I used this method on my 3800sc swap.

Results may vary..

Air intake ducting: Compare the Fiero ducting to the 3400 ducting for inside diameter size. You may get lucky if the are similar. Distance from air box to throttle body is the next measurement to take. If you're near a bone yard search out for something you can modify to work.

Spoon


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"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut

[This message has been edited by Spoon (edited 11-25-2022).]