1981 Ford Bronco 300 Straight Six new exhaust

This is my 1981 Ford Bronco.
It has the 300 I6 in it and I recently swapped out the original manifold for some 1989 fuel injected manifolds, put on a 2.5" exhaust, and a Dynomax turbo muffler. The difference in sound and performance was amazing!

Next it needs a good bath, sat under a tree for a month while I collected parts.

Category:

Autos & Vehicles

Tags:

• ford
• bronco
• straight
• six
• 300
• 4.9
• exhaust
• 1981

[guyfrommybox]

how loud and deep is the new muffler from outside of the truck?

[milesaway1980]

@guyfrommybox I need to get an updated video of it, but the sound from outside the truck is great. It's got a nice, rich sound to it without being really raspy. It's not super loud at idle, but can definitely make some noise when it gets above 1500/2000 RPMs.

From inside, I can barely hear it until I get on the gas.

[milesaway1980]

Not that I know of. But I've seen some new computer controlled 4 barrel carbs that Holley is coming out with that I'd love to try. Fuel injectors in the venturis instead of fuel jets.

[milesaway1980]

Yeah, the 2 piece EFI manifold is great because they're a huge performance improvement for the carb motor and are STOCK. Can't beat that. I've heard nothing but miserable complaints about headers, so I'm glad I didn't touch them. With these, I can put them on and forget about them.

[milesaway1980]

With the setup in the video (1bbl with EFI exhaust), I got about 17 - 22, depending on my speed and terrain. It was awesome.

Have a 4bbl on there now, and it's getting a bit less, but I'm still working out the kinks. Know a few guys who get 18 - 20 with a 4bbl, so I'm hopeful.

[guyfrommybox]

@milesaway1980 Please do get another video up! Your trucks nice. I was thinking of getting one of these mufflers. Right now i have mine straight piped and i like how deep the sound is.

[evilperson86u]

Yeah don't put headers on unless if you upgrade the whole intake. The EFI Manifold flow just as good, and besides they only good for drap racing.

[seapeddler]

Has anyone tried the EZ-EFI system on a 300-6 yet?

[rocintrucker83021227]

You made a wise call by putting the 2 piece manifold on instead of headers. I have headers for my 1988 f-150 and I kept blowing the gasket out. And I baby mine I don't take it over 2000 rpm to shift it. Those manifolds are not quite as smooth as headers but they don't blow out gaskets. Peace

[Orttymonster1]

My 300 I-6 is getting about 15 mpg Combined Cty/hwy with the 1 bbl carb. really with all the torque this engine puts out the mileage tremendous. I'm going to install a Hydrogen Generator on mine to up the power and mpgs.

Nice truck! keep up the good work!