modifications
Posting Guru
Joined: Jul 2003
Posts: 1,028
Likes: 1
From: San Antonio
major mods that are popular is a ats,banks, hypermax turbo system kit. other wise its like any gas motor more fuel/air(80 parts air to every part fuel) mixture you can get in and out of the motor the more power you will have. water, nitrous, propane injection also all increase power. porting and polishing the intake and heads works too. the 1986 6.9 is a good motor with only one real problem head gaskets blow easier on these motors ether bore the holes out for the head bolts so you can run 1/2" bolts instead of 7/16" bolts or go to arp studs you will have to pull the motor to do ether one. congrats on the truck and good luck.
Senior User
Joined: May 2004
Posts: 119
Likes: 0
From: Wilkeson, Washington
Here is some easy things you could do: 1st cut out the soupbowl, this is the thing inside the air cleaner that looks like a bowl. Next route the air intake right next to the radiator, be sure and cut some of the extra metal out of the way, this way your getting alot more air to the motor. Then run 3-3.5 exhaust all the way back. All this might set you back about $300.00 with the exhaust being about $280.00 of it. I also have an 86 and she pulls the 31 foot TT easier now. Its no speed demon, just seems to pull the hills and not bog down near as much. You could always turbo it, seems like the thing to do here. Alot of help at this site, these guys are great with help. Congrats on your truck I sure like mine.
Elder User
Joined: Sep 2004
Posts: 577
Likes: 0
From: Peoria IL
If you wanna crap out 2000 $ you can get a turbo. That doesnt count labor and a new exhaust and intake system for the turbo. Sure does make the most difference though.
I cut out the soup bowl and ran a 5 inch intake behind the grille/ headlight. FREE
Exhaust is a 2 1/4" y pipe to 3" dumping in front of passenger tire. No muffler or cat. Mufflers look better in the bottom of my dumpster than on the bottom of my truck. (Police disagree)
Turn up your fuel pump also so it smokes a little under hard acceleration.
I cut out the soup bowl and ran a 5 inch intake behind the grille/ headlight. FREE
Exhaust is a 2 1/4" y pipe to 3" dumping in front of passenger tire. No muffler or cat. Mufflers look better in the bottom of my dumpster than on the bottom of my truck. (Police disagree)
Turn up your fuel pump also so it smokes a little under hard acceleration.
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 16
From: Nutter Fort, WV
Cut the soup bowl out of the air cleaner lid if you have one. Free if you have the tools.
Lift the air cleaner housing off the intake and compare the size of the holes. My 86 had a 4" intake throat and a 2.5" air cleaner throat. It changed to a 3.75" throat on the air cleaner in a matter of minutes. Free if you have the tools.
Next crawl under the truck. Look at the factory Y pipe. Then go to a muffler shop that can fab 3" exhaust. Start the 3" pipe so the two downpipes both dump into the 3" pipe and replace the rest of the exhaust with 3" pipe. As far as the muffler goes, if you can get away with some increased noise, use a three inch see through muffler. Less restriction is best on a diesel exhaust.
I made this intake scoop for my 86, works great compared to the small hole behind the turn signal that was the stock intake location. Took a couple of hours to fab the intake scoop and a couple of hours to cut out everything in the way to install it and then reinforce the radiator support to make up for what i cut out.
Scoop area went from something like 12 Sq In to 40 Sq In. which made a big difference.
When that is all done we can help you turn the fuel up a bit to take advantage of the extra air you have available.
Lift the air cleaner housing off the intake and compare the size of the holes. My 86 had a 4" intake throat and a 2.5" air cleaner throat. It changed to a 3.75" throat on the air cleaner in a matter of minutes. Free if you have the tools.
Next crawl under the truck. Look at the factory Y pipe. Then go to a muffler shop that can fab 3" exhaust. Start the 3" pipe so the two downpipes both dump into the 3" pipe and replace the rest of the exhaust with 3" pipe. As far as the muffler goes, if you can get away with some increased noise, use a three inch see through muffler. Less restriction is best on a diesel exhaust.
I made this intake scoop for my 86, works great compared to the small hole behind the turn signal that was the stock intake location. Took a couple of hours to fab the intake scoop and a couple of hours to cut out everything in the way to install it and then reinforce the radiator support to make up for what i cut out.
Scoop area went from something like 12 Sq In to 40 Sq In. which made a big difference.
When that is all done we can help you turn the fuel up a bit to take advantage of the extra air you have available.
Trending Topics
Postmaster
Joined: Jul 2003
Posts: 2,976
Likes: 0
From: Rep. of Texas
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
Senior User
Joined: Nov 2004
Posts: 315
Likes: 0
For what it is worth, porting and polishing helps the flow. My recomendation (without spendig $) is to match the ports with the manifold (intake and exhaust). An easy way is to place the gaskets with the bolt holes lined up, mark the profile both on the head and exhaust and intake manifolds. With a dremel, grind to the line using about a 15 deg slope back inside the port. We did a lot of this on gassers and it improved the intake/exhaust flow, no 'step' between the manifold and head.
Postmaster
Joined: Jul 2003
Posts: 2,976
Likes: 0
From: Rep. of Texas
I called an engine machine shop for a quote on resleeving the cylinders and asked if the polishing would help but was told:
Polishing the inside of the intake manifold wont help on diesels, since their peak hp range is at lower RPM's...
Is that right?
Also, could you describe a "valve job" and what is porting?
Polishing the inside of the intake manifold wont help on diesels, since their peak hp range is at lower RPM's...
Is that right?
Also, could you describe a "valve job" and what is porting?
Posting Guru
Joined: Oct 2003
Posts: 2,438
Likes: 0
From: Monroe, WA
The intakes are quite large on these engines, so I can see where it probably wouldn't help much. I'd like to do some rough porting on the heads though to see what it would do for them. I think my original head gaskets are almost gone, might have to try it this spring.
Postmaster
Joined: Jul 2003
Posts: 2,976
Likes: 0
From: Rep. of Texas
Cylinder head porting...but not just a rough job- the complete thing.
http://www.sa-motorsports.com/diyport.shtm
http://www.sa-motorsports.com/diyport.shtm
