221/250 flexplates

Can I use a 250 auto flex plate on a 221 or are they balanced differently? Thanks

i believe they are balanced the same, zero balance, however there might be a difference in bolt patterns.

221 flex plate is a pattern all of its own.

redxm":2lthwf7s said:

221 flex plate is a pattern all of its own.

Click to expand...

It uses a 2.75" bolt center spacing, not 3.00" like the 250.

An XP 200 or XR 200 or XR 170 auto but so will an imperial bolt patern 1971 to 1985 200/250 Falcon or Cortina 157 or 160 teeth flexplate if you slot the six holes 1/8" each hole to the center.

You won't have any problems getting something to suit.

If your using a C4, you use the 157 factor flexplate, if your using a BW 35, use a 160 teeth item. The story is that early pre 1965 Ford 221, 260 and 289'S used 160 teeth flexplates, then went to 157 teeth in 1966. Ford Australia used the VoLVO 144/164 160 teeth flexplate when it got the same BW 35 gearbox

Thanks for your replys. I am indeed using a C4, so where do I find a flex plate that's correct for a 221? Can I use the 289 157 and remove the weight or is the crank pattern different?

xpcoupe221":2ibadsfh said:

Thanks for your replys. I am indeed using a C4, so where do I find a flex plate that's correct for a 221? Can I use the 289 157 and remove the weight or is the crank pattern different?

Click to expand...

Yes, you can use the 289 157 and remove the weight, but you also have to slot the six indexed bolt holes inwards. Two things are required.

Some important info.


There are small (136), medium (157 or 160), and large C4 (164) flexplates. The Aussie C4 equipped engines had an intermediate 157 teeth size for C4's only. The 160 teeth item is rare as, but every Borg Warner 3 stage auto, Model 35/40/41/51 had the early 160 Small Block Ford Compact Fairlane ring gear.


Any early Aussie or US V8 157 teeth flexplate will work, but the 164 teeth item won't. Cleveland stuff is normally 164 teeth, 28 Oz un balance, but there are 157 teeth 28 Oz flexplates on most C8,C9, C10 equiped 289 and 302's.

An Aussie market 1964 C4 equipped Compact 260 or 289V8 Fairlane 160 teeth flexplate is super rare, and still has to be slotted to fit a small 221 I6.

for the 157 teeth, you'll have to:-


1. "neutral balance" it from the 28 oz 99% of them had [or sometimes 50 ounce unbalance].

That means a professional engine balancer will have to remove the 0.793787 kilo check weight (or on rare occasions, a 1.41748 kilogram weight). Ford did it by cutting out presses steel, or by adding a riveted bias check weight. The guy who does the engine balancing then has to do whatever is easiest to bring it back to perfect balance).

2. Then have a machinist slot the holes inboard to 2-3/4".

NB// All non ohc SBF's have 3" six bolt pitch centers, with one hole out of sync for indexing.

The C4 equipped Falcon or Cortina i6's 1971 to October 1980 have a 157 teeth flexplate you can use, but the same "slot the holes inboard to 2-3/4" requirement" to fit the 1965 to 1970 170188/200/221 engines.



You just have to do the changes. The one size fits all 4.0 DOHC starter motor fits all the wide block 1966 on wards engines, 157 or 160 teeth, as the pitch is the same and 3 teeth don't make a difference.


http://fordsix.com/forum/viewtopic.php? ... 08&start=0

addo":2ibadsfh said:

First picture shows the pre-250/crossflow PCD vs the later PCD.



Second one shows the comparative nature of the two flexplates for BW and case-fill C4. You can see where the balance weights are drilled off.

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xctasy":2ibadsfh said:

Addo's shots at top Left. 170/200/221 for 1966-1970. Has 2.75" pitch bolts at crank.

Addo's Right. Case fill 250 C4 flexplate.

My BW 35 auto flexpalte, 1983 item.

BW's have four bolt holes 9.75" appart. If you scale the flexplates via the drawing using the bolt holes, you'll posibly find the C4 one has 10.5" bolt centres. In addition, the C4 flexplate has its ring gear spot welded on, not riveted like mine. There are lots of balance holes that I don't have on mine.

Looks like gassed250 wins...by a nose!

Click to expand...

Talk to Brad Girwood at Atomic Performance Parts.

They have a standard C4 bolt pattern billet blank,

#306720 - Chrome Moly Flexplate Kit
Suit Ford 6 cyl EA-FG.

http://www.atomicperformanceproducts.co ... G_8276.jpg

It comes in only a 3" six bolt spacing, but Brad might be able to source one unmachined. From 1965 to date, the flaxplates have been 160 teeth items with no changes, and they will work on your engine if machined to suit the 2.75" crank bolt pitch fitted to the very early model (pre-metric) Ford 6 cyl engines (144, 170, 200, 221)

http://www.atomicperformanceproducts.co ... lates.html

While we are on the subject and sorry to hijack, can a C4 bolt up to an Aussie 200 or am i better off getting the 250 pre bottom end?

C4 is a straight bolt up, anything from 1968 to 1980 will fit. Only issue is the flexplates bolt pitch. Aussie over head valve blocks from 1965 to 1992 are wider than the US ones, so you have to find an Australian C8 bellhousing to fit it up. Most autos from 1965 to 1992 were Borg Warner 35 or 40's, but plenty C4's were found on tow pack or Taxi Falcons and some 72-81 Cortinas, generally the tall block pre cross flow or non alloy head x-flows in 3.3 or 4.1's from 1972 onwards.

From 1968, IIRC...the Aussie Fairlane "3.6 litre" got the C4 as an option on the base 221 in line six.

I have a crossflow c4 bellhousing, I’ve been trying to locate a local 250 pre with c4 complete, then drop my 2V head on and get running again.

A cross flow bell housing and C4 will work on any 200 engine, even the US pre 1965 design one.


(Ford Australia made a transitional factory wide block adaptor to move the little weak kneed small diameter flywheel and flexplates up from the Mr Puney-Verse 132 and 136 teeth items to the V8 spec sizes.They did this because Australian conditions didn't like small diameter torque converters or clutch plates, especailly when they were planing to have one standard block for the planned 250 and tall deck 200 engines. They fronted up with a much stronger block and different V8 size trans parts to beef up the strength. US 200's have always suffered from poor clutch clampiig and cracking rig gear on the small 2.77 and medium 3.03 bellhousing engines. The 157 and 160 bellhousing was a great first start. Ford USA went to a 157 and 164 teeth low mount bellhousing in 1968 with the US 250, and 1981 with the big bell 200, for the same reason).

All you need is an Aussie 160 or 157 teeth flexplate from a 188/221, or the 250 one redrilled to a 2.75" six bolt pattern. After 1986, they were metric bolt, but if redrilled to 15/32" bolt size, and slotted from 3.00 pcd to 2.75" pcd, you'll be line.

The Atomic flexplate above will do the job, or a stock one from a 72 -80 C4 200 or 250 I6 redrilled.

Ther's nothing stopping you now.

Thank you, now the other issue, how to go faster.