1975 250ci what can you all tell me about it?

[Anonymous]

I am looking at buying a 250ci that is said to have come from a 1975 Maverick. What all can you tell me about that year 250? I know very little about which years are desireable more than others. What type of ignition did they use in 75? What was the compression ratio like? etc.

By the way, I am planning on swapping it into my '66 Bronco, which currently has the 170. I've heard I'll have to relocate the motor mounts, but that's not a big deal.

Also, this engine does not have a carb currently. What are recommended carb replacement choices?

Unless there is something significantly bad about that year, I will probably buy it. I have been looking for a 250 for a while now, and this is the first local one I have run across.

Thank you,
Morgan

 

[CZLN6]

Howdy Back Morgan:

Q-I am looking at buying a 250ci that is said to have come from a 1975 Maverick. What all can you tell me about that year 250? I know very little about which years are desireable more than others. What type of ignition did they use in 75? What was the compression ratio like? etc.

A- The '75 250 is a good engine combo. It is physically taller than your 170 by about 2". The pan will likely be a different configuration too. Take a close look at the two side-by-side. I'm away from home now and my references, but I seem to recall that the compression ratio in '75 was down to 8.2. The '75 will likely have a 1st generation of the DuraSpark system. The distributor will look like your stock '66 170s, but does not have point, and has typical vacuum and centrifugal advance built in.

Q- By the way, I am planning on swapping it into my '66 Bronco, which currently has the 170. I've heard I'll have to relocate the motor mounts, but that's not a big deal.

A- Along with motor mount fabrication you may need to move the radiator forward as the '75 has a longer shaft waterpump and crank damper.

Q- Also, this engine does not have a carb currently. What are recommended carb replacement choices?

A- The '75 250 will have either a Carter RBS or a Carter YF. For performance and simplicity the RBS is preferred (by me), as it has slightly more CFM thatn the Y- 215 vs 197. Neither carb is very long lasting and both are susceptible to dirt contamination especially with the stock automatic hot air choke. Both have a weak accelerator pump system that seldom lasts more than a few years. Keeping either clean with a once a year spray down with a good carb cleaner and running an ocassional can of fuel system cleaner through will help.

I seem to recall from other posts that the Broncho has a specific oil pan and some clearance issues on the underside. Overall the 250 should make a very nice upgrade for a lighter '66 Broncho. The 250 is quit torquey. The 250 oil pan is not interchangeable with 200 or 170s.

About the only down side to this engine is the huge quench height FoMoCo left. THis is particularly a problem as CR rises, but a 8.5 or less, it is not much of an issue.

Hope that helps.

Adios, David

 

[Anonymous]

Thanks for the reply. I had forgot about needing to mod the oil pan but that's not a big deal either. Lately I've been getting kinda handy at metal fabrication, and I kinda enjoy it too. One thing I was not familiar with is quench height. What is it? And can anything be done about it? It wouldn't be a problem now, but in the future I will probably do a few mods to the engine to get a few more ponies. Right now I'm just wanting to get an engine swapped in before a big spring trip I have planned. I like the 170 but I'd sure like to have a little more get up and go. The carb will be a short term solution as I plan on converting the engine over to fuel injection in the near future. I think I'm going to hack the intake log and fab up a better designed manifold, then plumb some injectors in and run it with a MegaSquirt EFI computer.

 

[Anonymous]

One other thing. Is there a significant increase in horsepower between the 200 and the 250? I believe the 200 is a direct bolt in swap. Especially since the bronco came with 200's. I don't mind making the changes for the 250 to fit, but is it the better option or should I consider the 200 instead?

 

[CZLN6]

Howdy Back:

Either the 200 or the 250 will make a nice improvement in your Broncho. The 200 may be a little simplier to swap because your 170 pan and pickup may be able to be adapted to a 200. You can also use the shorter shaft waterpump and pulleys. 200s used both the long (later) and short (earlier).

The 250 will definitely have more low-end torque- which is nice for 4 wheeling and a little more forgiving in any situation.

Either engine can be modified to perform well, but just because the 250 is 25% larger in displacement then the 200 don't expect it to hold that ratio in the HP department. Regardless of what you do they will still have a relatively small bore, limiting the size of valves and intake. Cutting off the log will lessen that obsticle some.

Another plus (or two) for the 200 is ease of availability, parts, and no quench hurdle.

The quench issue has been discussed in several previous topics. Try doing a search. I'm at an RV resort in Mesa, AZ right now and don' have much computer access time. If you don't find anything, ding me when I get home around 3/5 and I'll fill you in on the problem and possible solutions.

Adios, David