All Small Six ‘66 Bronco 170 vs early Mustang 170- same?

This relates to all small sixes

DrDave

New member
Just bought a ‘66 Bronco with a 170. Seller said it was rebuilt and maybe out of similar era Mustang 🤷. Would they be the same engine?
Thanks,
Dave
 

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Hi and welcome to the Ford Six forum! Yes if you decode the Blocks Design / Casting numbers you will find that these small six engines were first designed for use in the Ford Falcons, but they were installed in many other Ford and Mercury Models. There are slight differences when used in some of the models like a Bronco with 4 X 4 in order for the 170 engine to fit into that chassis it needs a specially designed oil pan, oil pump pick up tube to match that oil pans shape, and also a different dip stick & its tube, otherwise there isn't any other major difference to the block, head, or other parts.

As far as if it has a Solid Lifter or Hydrolic Lifter Camshaft Ford went to all Hydrolic Lifter Cam's in most of the 1963 year models the exceptions were in the 144 engines and some 170 engines that were used in the Econoline's, & Ranchero's, maybe in a few Bronco's, that still used the solid lifter cam's a few more years past 1963. I would say it's not likely they are solids but if I could hear it run then could tell immediately as the solid lifters have their own unique sound ticking / clicking. if the engine was changed out and is from a Mustang then no way and if you pull your valve cover and don't see an adjustable rocker arm assembly then there would also be no way they are solids. Best of luck on your new Bronco Edited
 
Hi, X2. The quick check is if you have 3 freeze out plugs on the passenger side you MAY have the original engine. If you have the later 5 freeze out plug block it is probably a 200 engine from another car.
After all these years many engines and engine parts have been changed out.
Read the tech section here and learn more about your engine and the different versions of the small Ford six. Good luck
 
Thanks to you both! As I may have noted already, the engine goes flat and sputters at RPMs above about 1300 but otherwise runs ok. Starts instantly regardless of the temp and idles perfectly. Looking at fuel filters and whether the vacuum advance next is working next. Typical process of elimination:-)
 
Hi, X2. The quick check is if you have 3 freeze out plugs on the passenger side you MAY have the original engine. If you have the later 5 freeze out plug block it is probably a 200 engine from another car.
After all these years many engines and engine parts have been changed out.
Read the tech section here and learn more about your engine and the different versions of the small Ford six. Good luck
Oh, and BTW I did notice a hole on the drivers side where the dip stick “should” go but it’s plugged and on the passsngers side! Was confusing but makes sense if the Bronco blocks required it replacement.
 
The soft plug at the front old draft tube spot tells me the block is no later than 66. I know for a fact that 68 does not have it and I have never seen one in 67 but cannot 100% say the 67 did not have one but with saying I will put that at 99.9% no 67.
 
Nice Bronco! 1966 is my favorite. You may want to get a copy of the Falcon Performance Handbook so you can identify which block and head you have with the casting number decoder.
 
Looks solid and well cared for. Mine was a northern NV resident with minimal rust in the floor drivers side and the rocker panels were pretty rusty. Rust has been repaired and rocker panels replaced, If you provide your head and block casting numbers we can identify which year they are made.
 
Yes this Bronco spent its entire life in Idaho (until now-Seattle area). It was very heavily under-coated many years ago and where the coating is now falling off the paint looks new.No rust except the standard stupid inner front fender wells 🙄. Ford must have attached salt licks to that area!
Not sure where those engine numbers are but I’ll find and send over. Thx for the research offer😊
-DaveM
 
Hi, the 144, 170, and 200 have 3 water pump bolts and the 250 has 4 water pump bolts so check that. The 200 went from 4 main bearings and 3 freeze out plugs to 7 main bearings and 5 freeze out plugs as a major design change. Good luck
 
250 would take some mods to fit in an OEM 170/200 vehicle. (@ 2" taller and 1-1/2" wider). If the starter is above the oil pan, it is not a 250. 250 uses same starter and Bell as the SBF V8.

200 starter location - "High Mount"


250 starter location - "Low Mount" (same as SBF)

.

have fun
 
Both the 200's & 250's of all years will have the 5 Freeze Plugs in the short block, X2 yes check the starter location. Another quick way to spot the 2 engine sizes is by counting the Water Pump mounting bolts a 200 has 3 and a 250 has 4. Best of luck.
 
4 fan bolts… 😆😆😆 I may be dumb but I’m not stupid! On second thought, now that I count the pump bolts again I count 3. I believe I counted the lower one from both sides thus 4 🙄🤦! Also the starter is higher and so…. a 200!(?).
BTW, per the stuttering issue, the new vacuum advance made a big difference!
 

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