Hi all,
I just bought my son a really nice looking 85' Bronco "Roll Along" edition. 351w, C-6 auto, 9" limited slip rear, tow pkg and decent 31's on alloys. Looks great, runs great, even the a/c is ice cold. Here's the kicker, he hates driving it because it is so big. I think he may have a depth perception problem but then again, he does great in my wife's Honda so it will be a smaller car for him and I will keep the Bronco for myself. I was not at all concerned about power (or the lack of it) when he was to be the driver but I want more. It has a 2bbl feedback carb and all original exhaust. I can swap an intake and 4bbl carb on but what about the exhaust? Th Y pipe looks like 1.75" of choke point. I don't want some high dollar, hi-po, monster; just a little more all around go. This Bronco will see 90 percent street, a little trail use and may have to pull a 3,000lb trailer up some mountains once or twice a year. I am looking for some advice from those in the know. I can do a performer intake and 600cfm 4bbl carb and was thinking about opening up the exhaust from the stock manifolds back. I read several places that the stock manifolds were not so bad but the y-pipe is. Is there a free flowing y-pipe available for these???Are the stock manifold okay or are headers a "must do". Thanks in advance for any input.

 

those stock exhaust manifolds are the chokers... get some long tube or even some shorty headers on there with the 4V intake and you will notice a big difference. the shorties will bolt right up with nothing else needed. the long tube headers would need custom exhaust work.

 

You might want some lower gears in it. There are some exhaust conversions out there and they will help, but they come with a high price. Spend your money like Hemieater said first and if there's some left look at the manifold back.

 

Thanks for the advice guys. I'm not looking for huge performance, just a little better than it's got, so I think the shorty headers make sense for installation to the stock y-pipe. There may be more to come later though;>)

 

Any smog issues? Make sure before you get the sawzall out....

 

Good point!
I live in Arizona and this rig will have to pass emissions every year. A coworker just said his son told him the feedback carb on my Bronco is junk and I should just start with a different 2bbl carb. This guy said the feedback carbs had low power and did not do anything for fuel economy either. Any opinions out there in Ford land? Thanks again for the help.

 

Oop's almost forgot,
How does this feedback system work and is there a way to bypass it or eliminate it if I go with a different carb?

 

Feedback carbs are "adjusted" by the engine computer. Never had one apart, but I think some use metering rods to keep the air/fuel right. Electric choke, too, I think. And, they have a purge set up so fuel doesn't evaporate after shut down.

The problem with these is the vacuum tubing and wiring all over the place. Once something goes bad, it's hard to sort through all that. If someone has torn part of it out, good luck.

But, in working order, they are tolerable. Not high performance, but tolerable.

Find out what your smog rules are. Pass at pipe, or do they do visual as well?

Once you find that out, you'll know what you can get away with.

 

Smog check here in AZ is not too bad. Pipe test, gas cap test and you're free to go. I've never seen them pull an air cleaner but they do pop the hood just to make sure you don't have anything too unusual going on under there. It really runs good, just a little underpowered. Swapping the intake and carb now sounds like it could be a hassle and possibly cause me to fail emissions later if they look too closely. Would only doing headers and exhaust (which are fine as far as the state of AZ is concerned) make much difference if everything else is stock? Or is bypassing the feedback system not that hard? Thanks again for all the advice

 

if you can get it 86& 87 came with a 351HO option (trucks did anyway) that had 600cfm holley and factory 4bbl manifold add some headers and your set

 

If its mostly visible, grind the mfg name off the aluminum intake and paint it to match the rest of the engine color.
This also works for street racing the chebby idiots who cant look part the obvious since they mail ordered their whole motor.

 

............

 

thanks stryder thats sig worthy right there.....lol

it wont fit in my sig dang it

 

Tony,
Just make sure you correct my lack of spell check/typing skills. Not sure how I hit the "r" instead of the "s", but you still get the point.