250 build

69stang_250

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Ok so I have somewhat of a plan for my build, but I know I will have questions along the way.

Here is the plan as of right now, or the plan in the works.

Head: mod log or AL? Still not sure on this one based on the exspince. Assuming machine work isn't too bad on the engine, I may just bite the bullet and get it. If so though, would you suggest the bare head or assembled?

Carb: torn on two barrel or small four barrel. In the future it will be a MPFI engine, so would the two barrel be ok for the time being?

Cam: 274/274. Not sure on the lobe sep just yet. I am thinking 110 based on the rpm ranges.

Pistons: the cylinder walls look ok, but there is not much of the cross hatch left on the walls. Once I measure I will figure out if I change the Pistons or not. Here are the questions. 255 Pistons worth doing if I keep the log head to get a 9.5 CR? Are the flat to 2.3 HSC Pistons worth putting in?

CR: 9.5 max if for some reason I stay with the log head. 10.5 max if I go with the AL head.

Bearings: I am pretty lost on which is the best. From reading on the CI web page they carried clevite bearings. Which do you prefer and where is the best place to get them now?

Rings: moly rings seam to be the best for all around use. So I'm going the them. Is there anything I should know about them other than the hone grit to use on the bores?

Rockers: I'm going to stay with my stock shaft mount but would like to get some adjustable 1.6 but have no idea where to get them or who makes them. I will be going to full roller rockers at a later date.

Timing chaine: from the looks of it, these are heavy duty enough in stock form. So I will be going with stock.

Rods: I will be getting them reconditioned and balanced. They are steel, so I am sure they will support the build just fine, but my question is if shot peening and ARP bolts are over kill for this engine? I'm hoping to see mid to low 200 hp.

Ignition: I will be doing a custom curved DSII with MSD controller. This seems to work great on these engines from what I have read.

Do you guys have any other input?

This car will be a weekend/sometimes daily car. I can deal with a rough idle, but relyability is the most important to me.
For right now the car has a 3.03 but will be going with a t5 a little later along with 3.25 or 3.55 rearend. I currently have a 4cyl t5 that I thinking of putting in once the engine is ready to go in, just to make things easy. Currently I have 3.00 gears out back and I have heard that the 3.97 first gear works really will with 3.00 gears. I will figure this out as I go.
 
When I built my 200, the cam company recommended a 108 LA for the standard trans. I have the 274/274.
Clevite bearings are good, there's plenty of sets on ebay. You should be able to find them at your local parts house as well.
You might as well go with ARP rod bolts while you're into it.
Remember that with a lot of compression you're going to need higher octane gas. I'm not sure that 10.5:1 would be happy on pump gas.
 
69stang_250":3fps4bff said:
Ok so I have somewhat of a plan for my build, but I know I will have questions along the way.

Here is the plan as of right now, or the plan in the works.

Head: mod log or AL? Still not sure on this one based on the exspince. Assuming machine work isn't too bad on the engine, I may just bite the bullet and get it. If so though, would you suggest the bare head or assembled?

if you want the aluminum head, contact does10s and see if he has access to one. i think at this point the answer would no, but ask first. and if he does have access, then pony up the money for one now, or hope to find a good used one later on.

Carb: torn on two barrel or small four barrel. In the future it will be a MPFI engine, so would the two barrel be ok for the time being?

a two barrel will be just fine. another option would be to use a two barrel CFI unit from something like a 3.8l ford V6, and use the megasquirt controller. at that point it would make it much easier to go with a multi port EFI since you would alreayd have the controller, and some tuning experieince.

Cam: 274/274. Not sure on the lobe sep just yet. I am thinking 110 based on the rpm ranges.

not a bad cam choice for a 250. 110 lobe separation angle is a nice compromise overall.

Pistons: the cylinder walls look ok, but there is not much of the cross hatch left on the walls. Once I measure I will figure out if I change the Pistons or not. Here are the questions. 255 Pistons worth doing if I keep the log head to get a 9.5 CR? Are the flat to 2.3 HSC Pistons worth putting in?

the 255 pistons are always worth doing with the 250. do run the numbers carefully though to make sure you are going to get 9.5:1 compression. that will work nicely on pump gas.

CR: 9.5 max if for some reason I stay with the log head. 10.5 max if I go with the AL head.

even with the aluminum head i would stay under 10:1 compression for the street

Bearings: I am pretty lost on which is the best. From reading on the CI web page they carried clevite bearings. Which do you prefer and where is the best place to get them now?

i have used to good effect over the years, clevite, federal mogul, speed pro, and trw. all were good pieces and i would recommend any of them

Rings: moly rings seam to be the best for all around use. So I'm going the them. Is there anything I should know about them other than the hone grit to use on the bores?

moly rings require a very smooth cylinder wall, and they break in very quickly.

Rockers: I'm going to stay with my stock shaft mount but would like to get some adjustable 1.6 but have no idea where to get them or who makes them. I will be going to full roller rockers at a later date.

early rockers were adjustable, and can be used on your 250 with no issue. check the classifieds here for guys selling sets of rockers. i dont remember what the stock ratio is off hand, it would be in the falcon 6 handbook though.

Timing chaine: from the looks of it, these are heavy duty enough in stock form. So I will be going with stock.

not a bad choice, but if you are feeling a bit rich, contact does10s and see if he will build you a double roller chain for your 250.

Rods: I will be getting them reconditioned and balanced. They are steel, so I am sure they will support the build just fine, but my question is if shot peening and ARP bolts are over kill for this engine? I'm hoping to see mid to low 200 hp.

shot peening is optional, but a good option none the less. it strengthens the rods. if you do peen the rods though, do it AFTER polishing them, otherwise you lose the advantage.

as for ARP bolts, i dont consider them optional, i consider them mandatory. so pop for a set of those and have them installed. i have broken too many stock rod bolts over the years.

Ignition: I will be doing a custom curved DSII with MSD controller. This seems to work great on these engines from what I have read.

personally i would not use the MSD controller. you dont need it. i would go with the chrysler orange ignition box and wire it to work with your DSll distributor. check out www.gofastforless.com to learn how to wire the chrysler box to the DSll. i would also use the msd blaster lll coil. that combination worked great in my old 66 falcon.

This car will be a weekend/sometimes daily car. I can deal with a rough idle, but relyability is the most important to me.
For right now the car has a 3.03 but will be going with a t5 a little later along with 3.25 or 3.55 rearend. I currently have a 4cyl t5 that I thinking of putting in once the engine is ready to go in, just to make things easy. Currently I have 3.00 gears out back and I have heard that the 3.97 first gear works really will with 3.00 gears. I will figure this out as I go.

i would go with a V8 T5 and 3.55 gears, that is a combination that works great for most setups. using the four cylinder T5 with more than the 3.00-3.25 gear would end up with a first gear that would be essentially useless, unless you were going to pull stumps.
 
Thirsty 250 can use a lot of air, the Offy tri-port type setup or direct 2bbl are good ways to make improvement in overall performance and drivability. I run a built 250 with 272 cam and alternate setups of 3-1Bbls or big 2bbl for fun. THe Offy' 3 1bbl Holley 1904's use a big truck carb on center for idle and outer carbs for progressive or synchronous as adjusted on the Offy linkage. The 3 1 Bbls run great with lots of adjustments capable (needed) . I swapped them out for a 500 CFM 2 bll with a plenum to the 3 log ports. The 4412-2300 is more consistent idle over different temps and plenty of performance with the 250/272 cam. A 'Cobra' T5 and 3.80 rear make a drivable setup with many capabilities.
I also have a stock MAverick 250/3.03 which needed a switch to a DSII ignition and 2Bbl 350 CFM carb on a simple adapter to make it a good driver.

have fun

'61 T'Bolt Six:
Ford C8DE 250 Six; Bored .070 over with TRW AMC 258 Pistons, Clifford Shot Peened Rods, Clifford 272H Cam, Cloyes timing set, Melling blueprinted HP oil pump, Fisher Dampener, Offenhauser Tri-Power 3X1 aluminum intake manifold adapter w/log Hi-Rise Plenum - Holley 4412 500CFM performance carb, GM HEI ignition trigger, Champion racing spark plugs., SFI 157 neutral balance-lightened racing flywheel spinning Centerforce Stage II Clutch, T5-Z Cobra 5speed tranny, Pinned engine mounts, Short throw Hurst Indy shifter, 8” 3.80:1 TracLoc Posi rear, Cal-type Traction Control devices and Shelby sway bar, Mustang front strut bars, Scarebird Disc front brake mod, Fabricated subframe connectors, tranny crossmember and rear spring mounts, 8 Point Roll bar, 5 point Safety Belts, Mustang 5.0 alum. racing radiator, Perma-Cool electric pusher fan, Holley fuel pump/pressure regulator, Hooker 6602 dual out longtube headers, Matte black/alum. 6=8 Clifford valve cover.Smithy silencers, Original tube radio, vacuum wipers and front fender Gunsights…
 
OSo I talked to Does10s and will be getting an Aluminum head for the build. At the most, I will be cleaning up the ports, chambers and doing some port matching. Now for the questions.

With the CS 274/274 and seeing track time every once in a while, would the single spring with damper be sufficient?

Do you guys think 10.1 CR is still too high for the engine? I will be running pump gas but don't Ming using octain booster if needed.

Any other info you guys may have about doing the AL head swap would be much appreciated.

Thanks everyone.

Oh, also, I will be going ahead and springing for full roller rockers from yella terra.
 
Usually an Alum head when used on many engines will let you raise the compression ratio an additional 3/4 to 1 point over an iron head. But the 250's are a different animal with some 250's having lots of deck height (my 77 is about .120 down the hole) it's not the best situation (and prone to detonation) when trying to raise the compression. I am going to use longer connecting rod and a custom piston to bring the deck height up. There are some other ways too like maybe stroking the crank a little too. I also plan to use an injection system using a combo of water & alcohol. Good luck :nod:
 
I am planning on using 255 Pistons to rais the deck height right now for budget sake. I have seen some off ground the crank and make a 273? But if I go that rout it will be way later down the road. For what I will be doing with this I can't justify spending so much on forged Pistons. I know they will free up some HP and last, but the AL head and roller rockers are taking up a lot of my budget.

All in all, once I get the head, assemble, and cc it, I will adjust fire from there.

Here is a good question. Have any of you used the old TBI on these engines?
I have a few ideas running though my head on the injection and this is one.
The other is taking the fuel injection set up out of an old 77 280z I have back in Louisiana and adapting it to this engine. Still doing research on all that though.
 
What are your guys opinion of the shaft mounted roller tip rockers? Thinking about getting a set from does10s since they are available.
 
69stang_250":3gbzxdl8 said:
What are your guys opinion of the shaft mounted roller tip rockers? Thinking about getting a set from does10s since they are available.

in my opinion, roller rockers, whether just a roller tip, or a full roller rocker, are always good. the reduce side loads on the valve guides, which is always a good thing.
 
Yes I agree, kinda wondering more if you guys had any issues with them or if you think for the price that the full roller set is a better rout?
 
Better double check the combustion chamber size on the aluminum head before getting those 255 pistons. IIRC they are about 52cc and with the 255 pistons you would be looking at about a 10.5 to 1 or more static compression ratio.
 
I am going to check the chambers first thing once the head is assembled and everything. I have read different things on the chamber sizes. 52-56 cc from what I have read. I am hopping it is 56, but will adjust fire as needed. Do these engines just not like compression, iron or aluminum head? I would have thought 10.5 with the AL head would be ok, but it seems most keep it 9.5 or lower.
 
Oh they like compression...just want you to be aware of what you might end up with and that you are ok with it. As long as you have decent pump gas and not too much timing you should not have detonation issues and the alum head should be more forgiving. The 274 cam should also help with the dynamic compression as well. Keep us posted!
 
I am going to try and keep the CR between 10-10.5. Looking at the Pistons and cyl walls yesterday, got me thinking about decking the block and keeping the Pistons that are in it right now; that is if there are no cracks or anything when I pull them out and inspect them. I am going to see what the most cost effective rout is once the head is here and asymbled.

I am not sure how accurate the CR cal on the classic inclines site is, but:

Head cc ( assuming 56 cc head as cast ): 56
255 piston cc: 1.5
Bore( using stock): 3.68
Stroke: 3.91
Deck height ( assuming stock .120): .035
Head gasket crush: .050

CR = 10.4

This is using assumptions only. I plan on cleaning up the chambers, which I have read can gain a cc or two. This will drop it down to 10.2-10.3. These are fine numbers with me, but again will adjust fire as needed. Now here is a question for you guys. What have your stock 250 deck heights read when measuring? The falcon hand book says between .120-.150. I have to get a gauge and measure mine before I take it apart, but I'm just curious.
 
I'm not sure what the original deck height was on my 250 but with my 255 pistons my deck height measured out to be .027
 
Had the engine been rebuilt before? Or resurfaced?
Oh, and btw. I love your Mav! My dad had a blue 71 while I was growing up till my mom hit a deer with it. Brakes weren't the greatest back in the day lol
 
69stang_250":1ng5pan3 said:
Had the engine been rebuilt before? Or resurfaced?
Oh, and btw. I love your Mav! My dad had a blue 71 while I was growing up till my mom hit a deer with it. Brakes weren't the greatest back in the day lol
Thanks! And no the engine had not been rebuilt before. During my rebuild the block was decked just enough to clean it up...maybe a few thousandths at most.
 
That sounds about right then. I know the 255 pistons raise the deck 0.085. So that brings the deck to .035 if it started at .120. so probably .008 to clean up the surface.
I am about to head to the parts store to pick up a ridge reamer, then go clean up the engine and do some measuring. I will post some pics today of the progress.
 
So after doing some measuring today, the deck height on my engine is .112. Looking at all the components, It's hard to tell if the engine has been reducible in the past. If so it was done with all ford stamped parts, but anyways..... The 255 Pistons are out of the question. New plan: 2.3 HSC Pistons and deck the block accordingly.

While inspecting the cylinders, the ridge on the top seems to be the cylinder, however, the bottom of the cylinder has a small ridge on each side but not on the outer sides. I'm guessing that is just from how the piston rides. With that I am going to take it to the machine shop and get them to put a bore gauge in there and see how much it needs to be bored. This is to make sure it's a true round cylinder.

Now for a few questions.

Small pin under the rope seal on the rear main cap? I watched a vid on YouTube where an old ford mechanic said to remove it because it causes the seal to leak. Is this true?
 
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