All Small Six 250 vs 200 for a daily driver in Bronco

This relates to all small sixes
J

jba6555

New member
Hello all. I figured you guys were the ones who could best steer me in the right direction. I have a 72 half cab bronco that I daily-drove 20 years ago that I would like to daily-drive again. It has a 200 with a three-speed currently. I also picked up a complete 250 with a c4 out of a 76 maverick. So I have both available.

I aim to build a nice daily driver with enough power to run an auto and possibly a/c. At times I think I would like to put an AOD behind it, but then I start adding up the cost to get the adapters and the extra power needed to make that work and think it probably isn't worth it. However, the thought of overdrive is appealing.

What would you guys suggest is the best and most cost-effective way to get to the power necessary for that application?
 
Though the 250 six isn't a direct bolt in in place of a 170 or 200 Six it is still possible with only a little extra work (you would need to weld up a custom 4 X 4 oil Pan and Pick up tube from the parts of the 170 / 200 six's oil Pan. Many of our site members have done this swap in their Bronco's. As far as an AOD Trans goes they can be bolted right up to any of the 250 Six's using the correct factory parts since they also have the same 6 bolt SBF V8 Bell Housing Patterns as so many of the AOD's have so there isn't a need for using an adapter plate. Good luck
 
What performance mods are necessary to make it viable to power an AOD in a bronco? or for that matter a C4?
 
Hi, members here have used the 250 in broncos with good results. A big advantage is the SBF Bell housing that allows the use of more transmission choices. That being said, the passenger car C4 is a lighter version of the Bronco C4. If you want the easier to install Bronco C4, it will be a heavy duty "pan fill", and have the needed output shaft. Next, you need to find out if this will work with your transfer case adapter.
If you want to go with an overdrive automatic, I suggest you research what 4 WD setup will fit from perhaps a newer Bronco or Pickup.
Good luck
 
jba6555 said:
What performance mods are necessary to make it viable to power an AOD in a bronco? or for that matter a C4?
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A C4 is easy I like to use the 1971 up C4 Transmission from a V8 these have all the Factory Improvements and plus the Extra Clutches the Sixes didn't get, I install a TransGo shift kit a small Auxiliary Transmission cooler. In your case if you go with the 200 Six then you need the Case Fill Car trans and if you go with a 250 Six then you could use a Case Fill Trans with a 157 Tooth Flex Plate or you can also use the Pan Fill C4 Trans that's also a little stronger and uses the 164 Tooth Flex Plate. Other up grades that might make sense if there is lots of off-roading 4 X 4 use is adding more clutches an aftermarket Input shaft and maybe a Convertor with a little extra Stall. A SBF C6 could be used and is super strong I still install a TransGo shift kit a small Auxiliary Transmission cooler in them their only disadvantage is that they are heavier and will take a little more power to turn them over the C4's.

For the AOD depends on the year Trans you start with you can use the 4R70W wide gear set or just start out with the later transmissions like the 1995 & 96 F and E series version that will have that wide gear set already in them. I install a TransGo shift kit a small Auxiliary Transmission cooler, if you go with one of the AODE or the 4R70W then you need a dedicated Electronic Shifter Control for them.
 
Thanks guys lots of good info there. Is a stock 250 sufficient for running a c4 in a bronco? What about an AOD/4r70W? Is a stock 200 sufficient to run a c4?
 
jba6555 said:
Thanks guys lots of good info there. Is a stock 250 sufficient for running a c4 in a bronco?
Click to expand...
Yes for sure many of the 250's came stock with a C4 behind them starting in their first year of 1969 and almost to the end of their production, in their last two years though they got upgraded to a C5 with a lock up convertor. .
jba6555 said:
What about an AOD/4r70W?
Click to expand...
Yes it could do that just as easy.
jba6555 said:
Is a stock 200 sufficient to run a c4?
Click to expand...
Yes for sure many of the 200's came stock with a C4 behind them starting in 1965 and almost to the end of their production, in their last year though they got upgraded to a C5 with a lock up convertor.
 
i like my car-like 5 speed (C sig) but the AOD (kick dwn or TV cable) or 4r70w (electronic control) would B nice (OD gear in there).

When 'doing " a vehicle the research & plan (budget 4 most of us) comes 1st. As an auto is a system & every prt wrks together toward that end (from cam thru tire choice) U must come up w/1 U stay w/thru to completion. Changed components or the plan mean poor decision or not enuff research (well, I guess technology might have changed during ur production).

The same ol same ol: "What is ur application?" answ will guide the plan (80% of the RPMs). Mall craw?, show?, street?, strip, 2 lane black top, stop'n go commute (ad infinitum)~

BTW: last few yrs ('75 on?) U could only geta bronk w/the bent8, C4 (or 3 speed top loader)
 
My 66 weighs about 3900 lbs without a roll bar on 30" tires and a 250 six just as point of reference, don't know what is on yours, large bumpers, big tires, winch etc. In 1966 the 289 was introduced to the Bronco with a c4 and that apparently was an acceptable driving experience. The 289 is about 13% more cubic inches than a 250 so it should have about 13% more power. Keep in mind I am guessing that a 250 with a torque/rv cam, 9 to 1 compression, 3 angle valve mod, DSII ignition would be enough to equal a 289. Attached to a c4 you could assume it would be sufficient depending on your definition of sufficient. Now if considering the AOD I would suggest calculating your axle ratios (4:11 likely but verify), tire diameter, AOD overdrive ratio as this might be too much for the 250. As you know there is nothing about a Bronco that is even remotely aerodynamic.
As far as ac I don't know how much hp that uses.
 
Actually you might be ok with the AOD/250. You could shift to third if needed for a steep grade and still have the overdrive available for level terrain. Not sure of the power consumed by the AOD compared to c4.
Probably could have added previously that the driving experience with the 250/NV3550 is easily sufficient for me. A vast improvement over the 200/3 speed. Comfortable highway cruising at 65+ and even the steepest grades I easily maintain speeds of 55 in fourth gear with a stock 250 that had about 80,000 miles on it claimed by the guy I bought it from and he did a valve job on it also. Using an automatic would change the performance slightly of course but this may provide some insight for you.
 
yes, "C4 is least parasitic of the autos" is what I all ways heard.
A modern auto is electronic (see bold, my last post) and would need
a stand alone (read: expensive) controller. 200/250 and C4 came in OE rigs. In
'72/3 (a yr or 2, '73/4?) even a bronk hada 200. I bet it could be ordered witha C4.
The i6 rest0mod on this side of the pond (usta get laughed at by the lard as$e$) is the
250/4.1. Being 'stroked' (tq) has advantages in a bronk st drivers dont need (they want HP
achieved in higher rev.s) unless just 'light to light driving' (ie multi short 'drag-like' runs). So
back to the eternal automotive Q: "What is [U]the exact application[/U] for this vehicle?"
AND
the eternal bronk issue: "Itsa [U]multipurpose[/U] vehicle." - cant B all things to all ppl. U must
pick one (rd? off rd?) or suffer the consequences of 'good at a couple things, not great at anything". I
shade it a good bit to 'off rd' (i6, big 1V, fairly low gear 1st). U may B urban there. I do some DD and that's Y I
have an auto transmish car. I hate shiftin (cept ina 'truck'). Trucks R more 4 wrk (& the clutch helps w/that). BUT
"to each their own" !
BTW: 200 gota AOD oe as well (like my fox wagon)
 
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chad said:
i like my car-like 5 speed (C sig) but the AOD (kick dwn or TV cable) or 4r70w (electronic control) would B nice (OD gear in there).

When 'doing " a vehicle the research & plan (budget 4 most of us) comes 1st. As an auto is a system & every prt wrks together toward that end (from cam thru tire choice) U must come up w/1 U stay w/thru to completion. Changed components or the plan mean poor decision or not enuff research (well, I guess technology might have changed during ur production).

The same ol same ol: "What is ur application?" answ will guide the plan (80% of the RPMs). Mall craw?, show?, street?, strip, 2 lane black top, stop'n go commute (ad infinitum)~

BTW: last few yrs ('75 on?) U could only geta bronk w/the bent8, C4 (or 3 speed top loader)
Click to expand...

My application is to drive around town most of the time. Highway speeds of 65, I doubt I would push it past 65 very much. Stock axles with 31" tires.

What do you all suggest for the best value build for that type of power?
 
"...What do you all suggest...
100% stop'n go traffic w/speeds below 45 MPH? Whats this 65MPH, 10%?
How many mi/yr?
Me only:
The 3 speed it came with would do well. A 3 speed auto (which I like drivin around town (less shiftin) but we in merica usually havea coffee of something in the other hand (C4). I understand you Continental types do not uses car for ur dinning room.
aahahaha
OD is for over 35, 45a for long stretches of drving (in my mind) to save the engine &/or reduce fuel use...
200 / C4; 250 AOD but needs a 'kick down' or TV cable to connect carb to transmission. HTH~
 
jba6555 said:
My application is to drive around town most of the time. Highway speeds of 65, I doubt I would push it past 65 very much. Stock axles with 31" tires.

What do you all suggest for the best value build for that type of power?
Click to expand...
What is your rear axle ratio? Unless it's greater than 3.73:1, I would not recommend the OD trans. 1)As has been pointed out, aerodynamics mean the engine sees a relatively high load at high speed. It is easy to over-gear and have the engine in so much of a bind that economy is worse in OD, and power is terrible. Factory vehicles were bad about this 30 years ago, my f150 has terrible factory gears, and it runs better and is more economical in 3rd than 4th below 65 mph. If you have 3.73 rear-gear, in OD your final drive ratio is 2.61:1. That's asking a lot of a 250 in a brick-shaped truck at speed. 2) the internal power loss is more with the OD. Driving mostly in town this is a constant waste of gas. 3) Electronic automatic= $650+ for the stand-alone controller. AOD = TV cable mock-up, and it has to be right. 4) In town application, rarely over 65 mph- keep the original 3 speed, or C4.
Peace.
 
Definitely confirm your axle ratio as suggested, it's good to know all the relevant data. As far as I know six cylinder Broncos had either the 4:11 or 4:56 ratios.
It seems that an automatic transmission is non negotiable for your Bronco so:

A 200/C4 will have slightly less performance than what you had before and keep in mind that 65mph on the highway won't be much fun for extended periods because of the current low gearing and you probably don't want to shell out for axle gear changes which would most likely be too much for the 200 anyway. If your 200 is weak it may not maintain 65 mph with the C4 and 31" tires. But for mostly in town use it may be fine for you.

A stock 250/C4 will have no problem with 65 mph but will be revving fairly high due to you current axle ratio. The fact that you have 31" tires will be a minimal help so good to have.

As stated you are probably good with your 4:11 or 4:56 ratios and an AOD/250 but I have not seen this powertrain combo so all is opinion at this point.

Optionally, the 250 should attach to what you have now and only the pan modifications would be any real work.
 
ask Stormin Norman (Fairmont).
LTD/Marquis (nother fox body right after) had it I believe, in 1st 2 yrs (a real transition period - '82/3. For
carb/CFI too).
26/7 inch tire is a standard bronk tire (took 15 & 16 inch "GS" I believe was the designation). 31 inch are known to
fit well w/o fender trim. They need to be a bit narrow though (less than 10 inch).
Rear ends oem: 4.11, 4.56 and 3.50, all but the middle could get lock.

✓ on posts 15 & 16 (by'n large) otherwise (my opinion)
8^ )
Find rear end w/a rear jack up... chalk tire/DS... spin tire (1 time) & count revs for DS to come around to "0" again = rear gear
(4.11 = 4 & a tenth rev) OR see axel code. Report here w/ it's weight load (2780 lb or the 3300) to ID which of 8 it was. HTH
 
I drove that bronco back and forth to college 20 years ago. I rolled down the interstate with a 200 and a 3-speed. I know what that experience is like. Its totally doable its just annoyingly loud revving the motor that high. I am not sure if it has 4.56 or 4.11 but those were the options for 6 cylinders and the rear end has not been changed.

So again back to my original question, what modifications would you do during the engine rebuild to free up power without going overboard for the needs of a daily driver with overdrive?

Cam? 2V carb modification to the head? Headers? deck the block? I am curious as to how you would all tackle this project. I feel like when I read build/performance threads on here they are often trying to squeeze more power out of engine than is necessary for a daily driver in a rural town of 65,000 people.


I do appreciate all your comments.
 
The main problem with the Early Bronco's with either a 170 or 200 Six is not the amount of power the engine can make if you want to be driving it at a steady 65 to 70 or more MPH, its the Axle Gearing of the Original Package. It was designed to do a job well for its day and since you have owned it all these years and you all ready know well how it drives its not so much of a mystery how it would work with a 200 and a C4. You also asked about a 250 swap and using either a C4's or a AOD. You can make any of these engine and trans Combo's work and build them to accomplish the stated goals once you know which one you want to go with and which parts of the Bronco's Original Parts Combo that you want to keep and or must continue to stay with.

Here is how I see it the 200 is very easy since it bolts in and there is a well proven parts package to build them to great daily driver power level and they can be built on fairly low budget to, you will have to use the C4 with it (a Great Trans and a big favorite of mine) unless you buy an adapter Plate Kit to be able to go with one of the Over Drive type Transmissions or there is also an Over Drive Unit (the Gear Vender's) that can be bolted on to them to. When using both a 200 or 250 with a C4 the Axle gearing would need to be different like 3.50 or so this might not be cost effective. With a 250 you would have much more Torque than a 200 Six so you all ready are ahead with that package and there are also proven parts combos to take them even further too, you likely be happy with a near stock 250 Six, and the big advantage though is that you could go right with an AOD, a AODE , or even a 4R70W. which would work very well with those 4.11 or 4.56 axels that you have now (check your Door or Door Jamb Tag Code is important so that you can verify which you Ratio you have now) to me this is your best option to do and you would then be able to drive it like you would like at todays speeds with the engine RPM much lower and quitter. Best of luck
 
I wouldnt go even that far.

Start small, with what you got. Optimism that: DSII, carb'n ignition tune. See what you think. Do it right, tho - dont neglect.
I guess I'm an incrementalist.
May B its my science background?
Low cash flow (still w/a hi investment quotient, 10K$ in it now)?

"...squeeze more power out of engine than is necessary..."
U already decided on OD of some kind. The bronk is a multipurpose rig. Does a coupla things OK, no thing well. To customize means you're accentin on... ?
St driver it seams. Look at 'the Handbook' for standard approaches w/a i6. Pick a modern cam, build the motor around that. 80% of the use's RMPs, and octane you'll fill it with. Glad ur doin research B4 decision making. May be lots more ahead. Indoing so U will have a much better product than "just get going'. Congrats~
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(oh'n dont 4get the above:
 
jba6555 said:
I drove that bronco back and forth to college 20 years ago. I rolled down the interstate with a 200 and a 3-speed. I know what that experience is like. Its totally doable its just annoyingly loud revving the motor that high. I am not sure if it has 4.56 or 4.11 but those were the options for 6 cylinders and the rear end has not been changed.
Click to expand...
Scratch my post above, should have kept quiet. Since you've got 4.10 or 4.56 you don't want a non-lockup 3 speed automatic! RPM will be even higher.
 
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