• Mustang Forums
  • 1965 - 1973 Classic Mustangs -General/Talk-
  • Classic Mustang Specific Tech

Engine Flex Plate

  • Thread starter Thread starter geostang351
  • Start date Start date Dec 3, 2013

geostang351

Member
Mar 30, 2005
946
0
17
Danb., CT
Dec 3, 2013
#1
  • Dec 3, 2013
  • #1
Confirmation; an 86 351w requires a 157 tooth, 28oz fly wheel?
 
Last edited: Dec 3, 2013
2

2+2GT

10 Year Member
Apr 25, 2009
3,333
10
79
Southeastern Pennsylvania
Dec 3, 2013
#2
  • Dec 3, 2013
  • #2
Well, the 28 oz is important. What year and trans are you putting it in?
 

geostang351

Member
Mar 30, 2005
946
0
17
Danb., CT
Dec 4, 2013
#3
  • Dec 4, 2013
  • #3
The plan is a T5 from a donor 90-93 mustang. The weight balance is for the motor, not tranny....?
 

dennis112

15 Year Member
May 15, 2005
1,561
36
79
Amish Wonderland of Central PA.
Dec 4, 2013
#4
  • Dec 4, 2013
  • #4
geostang351 said:
The plan is a T5 from a donor 90-93 mustang. The weight balance is for the motor, not tranny....?
Click to expand...

Correct, the weight is motor related and the flywheel must match. All 351w's (any year) are 28 oz imbalance. The 5.0's were all 50 oz. Old 302's were 28 oz, but not really designed for a T5. The T5 probably uses a 157 tooth flywheel (none were 164). What you need is available through the aftermarket in 28 oz.
 
Last edited: Dec 4, 2013

rbohm

Founding Member
Apr 12, 2002
6,698
550
204
tucson,az
Dec 4, 2013
#5
  • Dec 4, 2013
  • #5
dennis112 said:
Correct, the weight is motor related and the flywheel must match. All 351w's (any year) are 28 oz imbalance. The 5.0's were all 50 oz. Old 302's were 28 oz, but not really designed for a T5. The T5 probably uses a 157 tooth flywheel (none were 164). What you need is available through the aftermarket in 28 oz.
Click to expand...

^^this^^
 

robert912005

Member
Sep 7, 2009
161
4
19
Evansville, Indiana
Dec 5, 2013
#6
  • Dec 5, 2013
  • #6
dennis112 said:
Correct, the weight is motor related and the flywheel must match. All 351w's (any year) are 28 oz imbalance. The 5.0's were all 50 oz. Old 302's were 28 oz, but not really designed for a T5. The T5 probably uses a 157 tooth flywheel (none were 164). What you need is available through the aftermarket in 28 oz.
Click to expand...
What do you mean "old 302's were 28 oz, but not really designed for a T5"?
 

dennis112

15 Year Member
May 15, 2005
1,561
36
79
Amish Wonderland of Central PA.
Dec 5, 2013
#7
  • Dec 5, 2013
  • #7
robert912005 said:
What do you mean "old 302's were 28 oz, but not really designed for a T5"?
Click to expand...

I was referring specifically to a change in manufacturing when the original 302 became the 5.0 AND the T5 was first used. The old 302 no longer existed when the T5 came out. The flywheels/flexplates are weighted differently for the 2 motors.

What was originally known as the Ford 302 began in 1968 and its basic form was used through about 1981. It had a 28oz imbalance crankshaft (the same as a 289) and its other SBF predecessors. In 1982 Ford redesigned the crankshaft counterweights to make it lighter. To make up the difference, Ford needed to use a different imbalance weight on the flywheel/flexplate and the harmonic balancer. (50oz imbalance) None of these are interchangeable between the 2 motors UNLESS they have been appropriately rebalanced.

The T5 was first available in Fords in 1983. Since the old 302 (28oz imbalance flywheel) was discontinued before then, they never had a factory T5 so no factory 28oz imbalance flywheels were available for it. Luckily the aftermarket has stepped up and now the T5 swap is an easy conversion for the earlier motor.
 
Last edited: Dec 6, 2013

robert912005

Member
Sep 7, 2009
161
4
19
Evansville, Indiana
Dec 6, 2013
#8
  • Dec 6, 2013
  • #8
i see... thank you for the explanation...
 
V

v8only

Active Member
Jul 3, 2003
2,378
22
49
Dec 7, 2013
#9
  • Dec 7, 2013
  • #9
T5 has nothing to do with the flywheel...you can run the old style 10" finger style clutch with vintage 28 oz flywheel if you wanted
 

robert912005

Member
Sep 7, 2009
161
4
19
Evansville, Indiana
Dec 7, 2013
#10
  • Dec 7, 2013
  • #10
Im not trying to hijack this thread but im going to put a t5 in my 65 coupe with a 302 and the next thing i need to buy is the flywheel. Any suggestions?
 

rbohm

Founding Member
Apr 12, 2002
6,698
550
204
tucson,az
Dec 13, 2013
#11
  • Dec 13, 2013
  • #11
robert912005 said:
Im not trying to hijack this thread but im going to put a t5 in my 65 coupe with a 302 and the next thing i need to buy is the flywheel. Any suggestions?
Click to expand...

what trans do you have now?
 

robert912005

Member
Sep 7, 2009
161
4
19
Evansville, Indiana
Dec 13, 2013
#12
  • Dec 13, 2013
  • #12
c4
 

rbohm

Founding Member
Apr 12, 2002
6,698
550
204
tucson,az
Dec 13, 2013
#13
  • Dec 13, 2013
  • #13
robert912005 said:
c4
Click to expand...

ok then you want a 28oz balance factor 157 tooth flywheel. here are six from summit racing that will fit your application. they vary from an inexpensive steel wheel to a high end aluminum wheel. for the street i would go with one of the steel wheels myself. these are all set up to handle a 10.5" clutch by the way.

http://www.summitracing.com/search/...n?SortBy=BestKeywordMatch&SortOrder=Ascending
 

robert912005

Member
Sep 7, 2009
161
4
19
Evansville, Indiana
Dec 14, 2013
#14
  • Dec 14, 2013
  • #14
ok thanks for the advice
 
You must log in or register to reply here.

Similar threads

R
Flex plate and starter issues
  • RJH46
  • Jun 24, 2025
  • Other Auto Tech
Replies
19
Views
968
Other Auto Tech Aug 19, 2025
nickyb
F
C4 Transmission
  • Fri Guy
  • Jan 23, 2025
  • 1965 - 1973 Classic Mustangs -General/Talk-
Replies
3
Views
746
1965 - 1973 Classic Mustangs -General/Talk- Jan 23, 2025
LILCBRA
M
For Sale C4 Transmission Package for 79-93 Ford Mustang
  • Mustang _Mike
  • Dec 20, 2024
  • Other Classifieds
Replies
0
Views
251
Other Classifieds Dec 20, 2024
Mustang _Mike
M
S
Car shakes when taking off help???
  • STANKYstangs
  • May 10, 2026
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
12
Views
169
1996 - 2004 SN95 Mustang -General/Talk- May 27, 2026
LILCBRA
FUEL FLEX HOSE KIT
  • 93gtmustang
  • Jul 15, 2024
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 2
Replies
33
Views
4K
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Jul 23, 2024
AeroCoupe
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1965 - 1973 Classic Mustangs -General/Talk-
  • Classic Mustang Specific Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?