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170 ci 6 Cylinder guys - Ive got a few questions

tymbo

New Member
Joined
May 7, 2018
Messages
12
Loc.
Louisville, KY
I am going to make an offer on a 67ish maybe 68 Bronco with a 170 6 cyl in it and I have a couple questions because my budget isn't going to afford me the luxury of an engine swap for a while. I used to have a 67 ford pickup with a 300 inline 6 and it ran great and would do well on the highway.

1. What kind of highway speeds are you getting with what sized tires?

2. Has anyone switched the gears to get better speeds with the 6 cyl ?

3. I saw that the head and intake are a single casting, so I assume the single barrel carb is pretty much the only option?

I guess that I am worried about it being underpowered and not getting the same satisfaction as a 289 or 302?

Any input would be appreciated. Thanks
 

JCBombardier

Jr. Member
Joined
Mar 23, 2016
Messages
122
It’s definitely more of “mild” driving experience. My top speed is a little over 60mph on a long straight road. 30” tires, 4:10 gears. It can be tough to keep it over 35mph on a steep incline.

I hope to convert to a V8 one of these days but it’s still a blast to drive in the meantime. Just don’t expect anywhere close to the acceleration you would get out of the 300 or a V8.





Sent from my iPhone using Tapatalk
 

okie4570

Contributor
Bronco Guru
Joined
Jul 16, 2012
Messages
9,227
Loc.
NW OK
I've got two 66' with them, yes they are under powered for the bronco imo. If you're just running around town they're okay. High way driving or any hills, it's not very practical imo. I did have a 66' with a 200 6cyl with 4.56 and it was like a rocket compared to my 170 with 4.11. All of those broncos had stock sized tires as well. Some folks have added a header and even a small turbo, but I've got no personal experience with those. IMO you absolutely won't get the same satisfaction as you would with the v8 :)
 

halfcab1969

Jr. Member
Joined
Mar 26, 2014
Messages
85
Loc.
Allentown
I agree with everything above. The 170 is very underpowered and not worth putting good money into. HP /$ Im saving my money for a v-8 swap. Lots of good info on classic inlines at https://fordsix.com/archive/www.classicinlines.com/Tech.html
I would only buy what you need to keep it running. I replaced points for a cheap petronix knock off, replaced fuel pump, and rebuilt carburator. It now runs great but there's no replacement for displacement.
 
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thegreatjustino

Contributor
Red Head Grease Monkey
Joined
Jan 23, 2002
Messages
15,624
Loc.
Stockton, CA
1. 60 miles per hour on flat ground with no lift and stock size tires. 25 miles per hour up steep twisty mountain roads.

2. If you go from the stock 4.11 to 4.56 to make up for the lack of power, your top speed goes down. If you go from 4.11 to 3.50 (or anything in between) top speed may increase but acceleration will be crap.

3. Without changing the head, yes. There are aftermarket intakes/heads that allow you to bolt on a 2bbl carb. They run around $1,600 on ebay.

It is underpowered and you won't get the same satisfaction as a 289 or 302. I have a bone stock '68 with a 170. Because of all of the above, I will never buy a 6-cyl Bronco again. Whoever decided to put the 170 in a Bronco was completely oblivious the the concept of power to weight ratio. I can't say enough bad about that engine in a Bronco.
 

73azbronco

Contributor
Bronco Guru
Joined
Nov 11, 2007
Messages
7,796
If it is a stripped truck, no weight, no top, a 170 is peppy around town. Slow accel above 45 with top end around 60 due to drag. NO uphill capability except 35mph in second. But it is "fun" to drive:) Probably gets the best mpg of any engine in the EB though.

My first "truck" was a 65 Ford van with the 170, and that weighed less than an EB, and was slow, I put in a 240 and that made it fun.

I would avoid any mods to that six, save the money for a v8 later.
 

B RON CO

Contributor
Bronco Guru
Joined
Jun 29, 2016
Messages
2,412
Loc.
Statesville, NC
Hi, my 66 came with the 170 and 4:11-1 gears and 31-10.5 BFG s. It was fine for beach driving and hunting trails.
If you are a hard core off road guy you will want a lot more.
It went 60 mph. Now it got a 2 barrel adapter brazed on the head. Check out Fordsix.com. Now the engine can breath. I also got 3:50-1 gears. I go 65-70 mph at under 3000 RPM. I also got a 200 block that I'm cleaning up and I'll put in a comp cam.
The 300 big six truck engine is much more then the small Falcon six, but is a big job to swap in.
The big Bronco used that drive line.
The six cylinder Bronco used a different 3 speed and a shorter transfer case adapter then the V8.
Good luck
 

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Viperwolf1

Contributor
electron whisperer
Joined
Aug 23, 2007
Messages
24,316
I know an early '66 roadster now sporting a halfcab with a rebuilt 200, 4.11 gears, 30" tires, power steering and C4 that I have witnessed doing 80 mph on flat ground. This was near Greeley, CO which is pretty damn flat.
 

bmbm

Sr. Member
Joined
Jun 16, 2007
Messages
575
170 six

Ford originally intended the Bronco to be a farm/ranch type vehicle with some country/farm road type use as far as I know. My 170 was swapped after several years of use for a 200 and then a 250 which is great for my usage.
You can drop a 200 right in and with a larger 1v carb and DSII ignition you will see an improvement. Check out fordsix.com for detailed info.
One of the main disadvantages is the 3 speed trans.
 

NC-Fordguy

Bronco Guru
Joined
Jan 30, 2006
Messages
1,317
Loc.
Bethel/Greenville NC
I agree with what's been posted concerning the 170. Extremely under powered.

The 170 still lives in my 66. The wife drives it and she is content with it. With it being an August 65 build date I decided to leave it original/stockish. I did change out the distributor to a centrifical advance DUI. Plugged the scv port on the autolite 1100. This eliminated the finicky load-o-matic system. Runs alot better with these mods.
 

blubuckaroo

Grease Monkey
Joined
Jun 11, 2007
Messages
11,795
Loc.
Ridgefield WA
I'm considering going the other direction with my '62 Falcon Ranchero. It was retrofitted with a 289, but I'm thinking of returning it back to a 170 or 200 six. I want to keep the "old car" driving experience on this project.
The difference here is with the vehicle weight. This car probably weighs only 2300 lbs.
So, I may be in the market for your old six cylinder parts.;)
 

Bdhand

Contributor
Sr. Member
Joined
Aug 15, 2015
Messages
712
I'm doing a frame off on my 66 and it had a newly rebuilt but bored over 170 in it when I got it and I decided to keep it and not spend the money. Right now my thinking is I don't care about going fast just drive it around here and enjoy it. That may change when all is said and done and I get it back together. I hope I am not making a mistake but it can always be changed to a V8 later after the build is complete. I have a 63 Falcon that has a 170 in it and I enjoy it. I feel your pain with the struggle.
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,833
170 is small, little more than half the displacement of a 300/302.
It is less then half the displacement of a 351 that is commonly swapped in.
 

sk1nw4lk3r

Sr. Member
Joined
Nov 7, 2015
Messages
507
Wife's 66 170 suckkkksssssssss

Everything everyone says here is right. I know it's better for originality, and it's a cute little setup, but the damn thing won't get out of it's own way.

I wanted to convert everything over to a 289 and c4, but she wanted to keep it bone stock.

I might drop a 200 into it, since it'll basically bolt right in, and at least give me a tiny bit more power.
 

rmk57

Sr. Member
Joined
Feb 24, 2016
Messages
580
My 66 has 44,000 miles and is a real nice running little engine. I just dont see any reason to make a bigger six or v8 swap, ever. Sure it's a little underpowered, but I knew that buying it and didnt expect to be passing very many cars on the highway anyways. Mine has 4.11 rear gears and p235/75/15's and at 60 mph your really pushing it. If there is any positives about the little 6 is that in town it gets around the same mileage as our 2014 Escape.
 
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1strodeo

Squirrel Watcher
Joined
Sep 15, 2016
Messages
3,596
Loc.
Wisconsin
One of the main disadvantages is the 3 speed trans.

Agreed, I have one with a 170 and one with a 302 and both suck on hills due to the 3 speed. I would drive my 66/170 to work on the interstate at 70-75 mph on 31’s, which I’m guessing wasn’t accurate due to the taller tires, but shouldn’t it read slower??
 

bmbm

Sr. Member
Joined
Jun 16, 2007
Messages
575
Concerning your original questions there can be lots of differences in condition and state of tune but my low compression original 170 would hit 65 on the highway but was revving pretty high and that was on 235 75 15s.
You can get a 2v carb adapter or some guys get a 1v carb from a 200 or 250 which can be adapted to fit.
289/302 swap will give more hp of course but at least for me the 5 spd od change the whole driving experience enhanced by the 250 to be sure which is a torque motor. Highway driving is enjoyable now.
Just drive it until you decide what engine/trans you want to go with.
 

B RON CO

Contributor
Bronco Guru
Joined
Jun 29, 2016
Messages
2,412
Loc.
Statesville, NC
Hi, only certain import heads and after market heads have bolt on intake manifold. The Ford USA heads do not. Good luck
 
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