1991 EFI 302 swap

[Tweaver]

Hello all. I am swapping in a 1991 EFI 302 to my 1973. This new motor was built with a 350 HP trick flow kit. I bought a NV3550 kit from wild horses and the bell housing adapter kit will fit a 1991 as well. I also bought the WH headers to fit. I think the HD clutch kit from WH 4x4 will work as well. My question is regarding the flywheel and the number of teeth. I remember seeing something on a forum stating that the bronco starters wouldn’t work with the mustang flywheel due to the number of teeth. Will I need to buy a new flywheel with the same number of teeth, and the same number of mounting holes as the 1991? Or is it as simple as just using the mustang starter? The reason I ask is because I have a high torque starter that was on the factory 302 and would like to use it if possible. If this is a legit issue, do they sell high torque starters for the mustang engines that will work, or what is the easiest fix? Thanks in advance for any help

 

[DirtDonk]

You need the bell housing for a truck preferably, so you can fit the larger 164 tooth flywheel. The flywheel for your engine will probably need to be from a 90s era truck with a 5.0 (not a 5.8) so that it will have the 50 ounce imbalance factor, rather than the earlier 28 ounce, that the bronco would have come with.
If you were running a 5.8/351 you could get away with the original flywheel as long as the bolt pattern for the clutch was compatible.
The bolt pattern to the back of the crank is the same no matter what.

If the engine crankshaft was originally for an automatic, remember to add the pilot bearing.
if you don’t already have it, you’ll need the adapter bracket for the clutch bell crank because the 91 engine won’t have the drilled and tapped hole in the boss at the back of the engine. Or will you be using a hydraulic clutch? Not sure if the mustang had that or not.

On the question of the starter, I’m not sure.
The mustang did use a unique setup that fit both the automatic and manual. If I remember correctly though, it is the same as one or the other of the starters that we usually go for trucks.
You can look it up in one of the application guides to see if the starter you have is going to be compatible with a manual transmission. But you definitely want a manual transmission starter.
My guess is that it should still be compatible, whether you use the mustang bell housing or the truck bell housing. As long as it was the same part number as an older manual transmission.
I don’t know all this for a fact from experience, but it would make sense that if it’s the same part number (for example a 3205) as the truck manual transmission, then it would work in your application.

 

[Tweaver]

Between the new NV3550 kit and the Trick Flow kit, I have the correct bell housing adapter and the new harmonic balancer. The issue that was mentioned in that other forum stated that the starter was damaging the teeth on the mustang flywheel. I gotta find that other thread to see what they did to correct it

 

[ba123]

You need to make sure the starter works with both count flywheel teeth 164/157 or you can’t use that starter. Try to find the specs for your starter and if you can’t, get a new one cause it’s not worth damaging and having to pull your engine or drop your trans.

If you do need a new starter, I love mine so far and according to the description should work for you as well, but check the Powermaster page to be sure:
https://www.summitracing.com/parts/pwm-9603

Not sure if this one or the 9604 is right for you.

 

[Broncobowsher]

Starters for a small block ford come in 2 sizes. Automatic and manual. Doesn't matter the number of teeth on the flywheel, it has to do with the offset of the ring gear from the back of the block. Ford ran 2 different offsets.

*** there is one HUGE exception to this, and it involves Fox Body Mustangs. The Mustang Tremec T5 manual transmission was an oddity that used a special flywheel and bellhousing. This odd mix of parts results in using the starter normally only used with automatic transmissions. ***

There are 2 different sets of flywheel teeth commonly found. The 157 tooth is typically a "car" flywheel while the 164 tooth is the "truck" flywheel. The car flywheel is typically 10" clutch, although in the last years they did manage to squeeze in a 10.4" as that was as big as there was room for. And it did help durability. The 164 tooth truck flywheel is typically an 11" clutch, but there were some only filled with a 10".
The size of the teeth is the same. So how do you squeeze 7 extra teeth onto a flywheel if the tooth size is the same? You make it bigger. (That's how they can get that larger clutch to fit as well). But as the flywheel gets larger, the starter needs to move away from the crank centerline as well. For small block Fords, the starter is indexed/spaced away from the crankshaft with the bellhousing. The "truck" bellhousing has the starter located further out than the "car" bellhousing. (Some full sized cars did get the truck bellhousing)

What parts do you need? Not the mustang clutch. 11" clutch should be part of the trans swap kit. That is truck stuff.
Mid 80's and newer flywheel from a 302 truck (need to match with the pressure plate). Someone can chime in on going from an old 3-finger to a newer diaphragm pressure plate (and matching flywheel bolt pattern). I am not the most up to date with what works.

For a starter to damage teeth on a mustang flywheel. This is getting weird in a Bronco world. There should never be a Mustang flywheel in a Bronco. But maybe they were referencing running it in a Mustang? Going back to that Mustang oddity I highlighted above. Mixing and matching manual/auto starters and getting it wrong. I could see how a starter gear not fully engaging/disengaging from a flywheel will tear it up. But a Mustang flywheel only comes in 157 tooth. Which requires a 157 tooth "car" bellhousing. If you put a 157 tooth flywheel in a 164 tooth "truck" bellhousing, the two will never touch. The starter just spins air.

 

[Tweaver]

Starters for a small block ford come in 2 sizes. Automatic and manual. Doesn't matter the number of teeth on the flywheel, it has to do with the offset of the ring gear from the back of the block. Ford ran 2 different offsets.

*** there is one HUGE exception to this, and it involves Fox Body Mustangs. The Mustang Tremec T5 manual transmission was an oddity that used a special flywheel and bellhousing. This odd mix of parts results in using the starter normally only used with automatic transmissions. ***

There are 2 different sets of flywheel teeth commonly found. The 157 tooth is typically a "car" flywheel while the 164 tooth is the "truck" flywheel. The car flywheel is typically 10" clutch, although in the last years they did manage to squeeze in a 10.4" as that was as big as there was room for. And it did help durability. The 164 tooth truck flywheel is typically an 11" clutch, but there were some only filled with a 10".
The size of the teeth is the same. So how do you squeeze 7 extra teeth onto a flywheel if the tooth size is the same? You make it bigger. (That's how they can get that larger clutch to fit as well). But as the flywheel gets larger, the starter needs to move away from the crank centerline as well. For small block Fords, the starter is indexed/spaced away from the crankshaft with the bellhousing. The "truck" bellhousing has the starter located further out than the "car" bellhousing. (Some full sized cars did get the truck bellhousing)

What parts do you need? Not the mustang clutch. 11" clutch should be part of the trans swap kit. That is truck stuff.
Mid 80's and newer flywheel from a 302 truck (need to match with the pressure plate). Someone can chime in on going from an old 3-finger to a newer diaphragm pressure plate (and matching flywheel bolt pattern). I am not the most up to date with what works.

For a starter to damage teeth on a mustang flywheel. This is getting weird in a Bronco world. There should never be a Mustang flywheel in a Bronco. But maybe they were referencing running it in a Mustang? Going back to that Mustang oddity I highlighted above. Mixing and matching manual/auto starters and getting it wrong. I could see how a starter gear not fully engaging/disengaging from a flywheel will tear it up. But a Mustang flywheel only comes in 157 tooth. Which requires a 157 tooth "car" bellhousing. If you put a 157 tooth flywheel in a 164 tooth "truck" bellhousing, the two will never touch. The starter just spins air.

I bought the 1991 motor out of a mustang with standard transmission. My motor is at the builders garage but I think my bronco flywheel has a different mounting bolt pattern than the mustang, correct? So if I buy a flywheel for a 1991 truck 302 with manual transmission it should work? When I bought this new NV3550 transmission from WH, they said the adapter kit would work for the newer 302s so hopefully no flywheel clearance issues with that. I should be able to re- use my bronco starter and clutch kit, correct?

 

[toddz69]

I bought the 1991 motor out of a mustang with standard transmission. My motor is at the builders garage but I think my bronco flywheel has a different mounting bolt pattern than the mustang, correct? So if I buy a flywheel for a 1991 truck 302 with manual transmission it should work? When I bought this new NV3550 transmission from WH, they said the adapter kit would work for the newer 302s so hopefully no flywheel clearance issues with that. I should be able to re- use my bronco starter and clutch kit, correct?

I think the Bronco flywheel (don't bolt it on the new engine) and the Mustang flywheel will have the same bolt pattern. If you get the ones recommended earlier in the thread, they will bolt up fine, including the '91 truck 302. Yes, you can reuse the Bronco starter and clutch.

Todd Z.

 

[Tweaver]

Thank you all for your help. Most of the big bronco companies sell the late model flywheels that will work for this motor. Thanks again.

 

[farmboy]

You need the bell housing for a truck preferably, so you can fit the larger 164 tooth flywheel. The flywheel for your engine will probably need to be from a 90s era truck with a 5.0 (not a 5.8) so that it will have the 50 ounce imbalance factor, rather than the earlier 28 ounce, that the bronco would have come with.
If you were running a 5.8/351 you could get away with the original flywheel as long as the bolt pattern for the clutch was compatible.
The bolt pattern to the back of the crank is the same no matter what.

If the engine crankshaft was originally for an automatic, remember to add the pilot bearing.
if you don’t already have it, you’ll need the adapter bracket for the clutch bell crank because the 91 engine won’t have the drilled and tapped hole in the boss at the back of the engine. Or will you be using a hydraulic clutch? Not sure if the mustang had that or not.

On the question of the starter, I’m not sure.
The mustang did use a unique setup that fit both the automatic and manual. If I remember correctly though, it is the same as one or the other of the starters that we usually go for trucks.
You can look it up in one of the application guides to see if the starter you have is going to be compatible with a manual transmission. But you definitely want a manual transmission starter.
My guess is that it should still be compatible, whether you use the mustang bell housing or the truck bell housing. As long as it was the same part number as an older manual transmission.
I don’t know all this for a fact from experience, but it would make sense that if it’s the same part number (for example a 3205) as the truck manual transmission, then it would work in your application.

Was reading your post and im installing a 2001 ford explorer 5.0 in my 72 bronco and running 3 speed manual trans, the block is at the machine shop doing 347 stroker work does that block have a boss in the block and the shop is balancing it to 28 oz so I bought new balancer ( old one was damaged ) is all 28 oz flywheels the same thanks

 

[DirtDonk]

The block bolt pattern for the bell housing is the same across the engine family (for the most part anyway) so car AND truck bell housings bolt right up.
The boss for the clutch pivot bracketry (bell-crank support brace) is there, but the threaded bolt hole will be missing on your new engine. Using the old clutch mechanism is not a big problem however, as you can either drill and tap a hole, or use an adapter bracket (such as our WH #8197) like this: WH Clutch Equalizer Adapter
You can use it as-is, or even modify it slightly like I've done in the past. Can't remember all the details, but I did something to make it easier to bolt up the bell housing with the bracket in place, or something like that.
Hmm, been awhile since I've done one. I'll have to get my buddy to snap a few pictures of his.

Regarding the flywheels, no they are not all the same. The bolt pattern to mount it to the crankshaft is the same across the lineup, but you still need one from a truck or heavy car application with the 164 tooth count. To retrofit a later or aftermarket diaphragm style clutch, you'll probably want to source one from a '90's Bronco or F150 with a 5.8/351 engine.
All the 5.0/302 engines would have been 50oz by then, but there were probably a few crossovers during the change-over to 50oz on the smaller engines. But someone else will have to provide that list, if you're going junkyard cruising.

And a starter for a manual transmission.

Paul