Bellhousings

Route666

Active Member
Aug 16, 2003
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Brisbane, Australia
Ok I didn't want to intrude on another thread, but it got me thinking.

Am I correct in saying 351 (C and W) and 302 blocks will use the same bellhousing?

What is a 6-bolt block, and what is the alternative to a 6-bolt?

Why are 78 - 93 302/351 different to 5.0L (1994 - 95) scattersheilds and different to 65 - 78 302/351? Is it ONLY because of the type of clutch actuation and transmission input shaft length?

Are 78 - 93 and 94 - 95 bellhousings made for long input shaft transmissions? Why are they different from each other?

If I buy a new 302 block, will a bellhousing or scattershield that will fit it be interchangeable onto a 351? Will it be a 6-bolt block? (I ask this because it seems to be the superior design, as it is mentioned specifically when looking at scattershields.)


Onto flywheels

Am I correct in saying any size flywheel will fit into any of these bellhousings? (As long as it is the right imbalance for the crank.)


Cheers!
 
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Clevelands use a different bell housing than the W or 302. Any 289, 302 or 351 W that was 1965 model or later had a 6 bolt bell housing. The 221, 260 and 289 built before 1965 models had 5 bolt bell housings. I don't know when the exact date of change was.
 
clevelands us ethe same bellhousing too, its the 351M that uses the big block pattern. 302-351W-351C all use the same 6 bolt bell pattern. Depths vary with trnasmission style. Balance factor changes with crank style. Some flywheels will accomodate the old 3 finger clutch, and some the newer diaphragm style, most aftermarket units will accomodate both. 164 tooth fly can accomodate an 11" clutch. Flywheel tooth count varies with bellhousing, mainly due to starter location.
 
Route666 said:
Ok I didn't want to intrude on another thread, but it got me thinking.

Am I correct in saying 351 (C and W) and 302 blocks will use the same bellhousing?

What is a 6-bolt block, and what is the alternative to a 6-bolt?

Why are 78 - 93 302/351 different to 5.0L (1994 - 95) scattersheilds and different to 65 - 78 302/351? Is it ONLY because of the type of clutch actuation and transmission input shaft length?

Are 78 - 93 and 94 - 95 bellhousings made for long input shaft transmissions? Why are they different from each other?

If I buy a new 302 block, will a bellhousing or scattershield that will fit it be interchangeable onto a 351? Will it be a 6-bolt block? (I ask this because it seems to be the superior design, as it is mentioned specifically when looking at scattershields.)


Onto flywheels

Am I correct in saying any size flywheel will fit into any of these bellhousings? (As long as it is the right imbalance for the crank.)


Cheers!
All 302's and 351's use the same bellhousing pattern ( with the above mentioned 351M excepted) The 65-68 289's do as well. The earlier small blocks ( 221, 260 and early 289 ) had a smaller 5 bolt bell pattern. The 78-95 bells are deeper to accomodate the longer ( 1") SROD, Tremec and T-5 transmission's input shafts.
 
Thanks for the info guys, I would like to expand further:

I've just only clicked just how exactly the same 351W and 302W are. They are exactly the same except for deck height right? Which means the only components that won't interchange are the intake manifold, exhaust manifold and crank, because of stroke length and main journal size. Is that correct?

Also I notice that the Lakewood catalogue doesn't specify flywheel tooth count, so how do I get the right one? Is it based on year range?
 
351LX said:
I am running the exact same 164 tooth C-4 bellhousing with my 351c that I had with my 302.


That means your 302 is pre 1982 or H.O. 302. Post 1982 non H.O. 302s use a different flywheel/Flexplate.

D.Hearne said:
All 302's and 351's use the same bellhousing pattern

:nice: 250 I-6 and 300 I-6 will also share the bellhousing mounting pattern as the Winsor family blocks.

Route666 said:
Why are 78 - 93 302/351 different to 5.0L (1994 - 95) scattersheilds and different to 65 - 78 302/351?

:shrug: Correct me if I am wrong but don't scattersheilds vary by the type of transmissions?

Route666 said:
Are 78 - 93 and 94 - 95 bellhousings made for long input shaft transmissions? Why are they different from each other?

Bellhousings are made for the tranny and can differ for different trannies.

Route666 said:
If I buy a new 302 block, will a bellhousing or scattershield that will fit it be interchangeable onto a 351? Will it be a 6-bolt block? (I ask this because it seems to be the superior design, as it is mentioned specifically when looking at scattershields.).....Am I correct in saying any size flywheel will fit into any of these bellhousings? (As long as it is the right imbalance for the crank.)

New non H.O. blocks can use the same bellhousing and scattersheild but not the same flywheel/flexpalte and harmonic balancer (as the 351W). Pre 1982 or H.O. 302 will share all four items. As you indicated this dating is specific to the crank not the block. ie if you put a 1976 crank in a 1988 block then go by the pre 1982 rules.
 
Route666 said:
Thanks for the info guys, I would like to expand further:

I've just only clicked just how exactly the same 351W and 302W are. They are exactly the same except for deck height right? Which means the only components that won't interchange are the intake manifold, exhaust manifold and crank, because of stroke length and main journal size. Is that correct?

Also I notice that the Lakewood catalogue doesn't specify flywheel tooth count, so how do I get the right one? Is it based on year range?

Oil pan is different too as are the brackets.

Lakewood scattershields can hold either the 157 tooth or the 164 tooth flywheels. The only difference is the starter location. The Lakewood has 2 sets of holes to accomodate this.
 
danny clemens said:
Clevelands use a different bell housing than the W or 302. Any 289, 302 or 351 W that was 1965 model or later had a 6 bolt bell housing. The 221, 260 and 289 built before 1965 models had 5 bolt bell housings. I don't know when the exact date of change was.

Stuck my foot in my mouth on that one. I've never put a bell housing behind a Cleveland and thought that I had read where it was different. It may have been the Modified I had read about. Thanks for posting the correct answer. I was able to learn something new.
 
dennis112 said:
Oil pan is different too as are the brackets.

Lakewood scattershields can hold either the 157 tooth or the 164 tooth flywheels. The only difference is the starter location. The Lakewood has 2 sets of holes to accomodate this.

...and the oil pump, pickup, pump shaft, and distributor.

I'll back up the scattershield info. My McLeod is the same as a Lakewood and it has two sets of starter mounting holes. I asked the same question during the summer before I bought it.
 
302 coupe said:
clevelands us ethe same bellhousing too, its the 351M that uses the big block pattern. 302-351W-351C all use the same 6 bolt bell pattern. Depths vary with trnasmission style. Balance factor changes with crank style. Some flywheels will accomodate the old 3 finger clutch, and some the newer diaphragm style, most aftermarket units will accomodate both. 164 tooth fly can accomodate an 11" clutch. Flywheel tooth count varies with bellhousing, mainly due to starter location.

This Georgia Southern graduate makes me so proud I think I will have another sip of water from beautiful Eagle Creek. I always keep some on ice in the frig!

HistoricMustang
www.historicmustang.com
 
havack said:
:shrug: Correct me if I am wrong but don't scattersheilds vary by the type of transmissions?

Ahh of course, the one thing that should have been most obvious to me about bellhousings and scattershields was left out.

I've never been good with years of parts, I would rather see things listed as "fits 6-bolt 302W, 351W/C and Tremec 3550/TKO 7.200" input shaft transmission." It just seems easier to me.

Anyway, thanks everyone for expanding my knowledge base! I'm also overjoyed that now I can break up all the projects I want to do a bit more and I don't need to get a very specific car (302, manual trans, AC, etc, etc). Now I can basically get any smallblock 69 sportsroof and I'll be happy.
 
I have run into several problems trying to install a 1979 351W in a 1969 Mustang that had a 302.

1) The 351W flywheel is the 164 tooth and the 302 flywheel is a 157 tooth. Obviously, the 1979 351W flywheel is a larger diameter. I think I will need to get a flywheel that is a 50 oz. balance that has the 157 tooth ring so I can use the original starter due to mounting issues to the bellhousing. I this was the flywheel found on the 1969 351W from the factory.

2) The 1979 351W came with a 4-bolt balancer and my pulleys won't work. I will either have to get an aftermarket balancer or get an original for a 1969 351W so the pulleys will work properly and have the proper balance.

3) To make things more complicated, I used the new water pump I had for the 1969 302 and put it on the 351W. The outlet on the original 351W water pump was on the driver's side and it is now on the pasenger side so it will match up to my new radiator. The pulleys are a concern again because of the water pump and/or the balancer/crank pulley issue noted in point #2.

I think these are the only issues I have run across so far. These may be easy issues to fix, but are frustrating nonetheless. I just thought I would add to the list of things that are or may be ran into when putting a 351W in place of a 302. I am open to suggestions as well.
 
OUFan22 said:
I have run into several problems trying to install a 1979 351W in a 1969 Mustang that had a 302.

1) The 351W flywheel is the 164 tooth and the 302 flywheel is a 157 tooth. Obviously, the 1979 351W flywheel is a larger diameter. I think I will need to get a flywheel that is a 50 oz. balance that has the 157 tooth ring so I can use the original starter due to mounting issues to the bellhousing. I this was the flywheel found on the 1969 351W from the factory.

2) The 1979 351W came with a 4-bolt balancer and my pulleys won't work. I will either have to get an aftermarket balancer or get an original for a 1969 351W so the pulleys will work properly and have the proper balance.

3) To make things more complicated, I used the new water pump I had for the 1969 302 and put it on the 351W. The outlet on the original 351W water pump was on the driver's side and it is now on the pasenger side so it will match up to my new radiator. The pulleys are a concern again because of the water pump and/or the balancer/crank pulley issue noted in point #2.

I think these are the only issues I have run across so far. These may be easy issues to fix, but are frustrating nonetheless. I just thought I would add to the list of things that are or may be ran into when putting a 351W in place of a 302. I am open to suggestions as well.


1: do not get a 50oz balance flywheel, the one off the 302 will do nicely as the 69 302 and the 351w have the same balance factor.

2: use the balancer from the 302 as well. it bolts on.
 
rbohm said:
1: do not get a 50oz balance flywheel, the one off the 302 will do nicely as the 69 302 and the 351w have the same balance factor.

2: use the balancer from the 302 as well. it bolts on.


I thought the 351W and the 302 used a different balancing weight. If all I need to do is put the 302 balancer and flexplate on my 351W, then I am dang near set. I then can use my 302 pulleys. By going to a passenger side outlet on my water pump from the original driver side outlet change the distance from the crank centerline to the water pump centerline?

The only other problem I have is I will need an adapter bracket for my power steering pump bracket. Thanks.
 
OUFan22 said:
I have run into several problems trying to install a 1979 351W in a 1969 Mustang that had a 302.

1) The 351W flywheel is the 164 tooth and the 302 flywheel is a 157 tooth. Obviously, the 1979 351W flywheel is a larger diameter. I think I will need to get a flywheel that is a 50 oz. balance that has the 157 tooth ring so I can use the original starter due to mounting issues to the bellhousing. I this was the flywheel found on the 1969 351W from the factory.

2) The 1979 351W came with a 4-bolt balancer and my pulleys won't work. I will either have to get an aftermarket balancer or get an original for a 1969 351W so the pulleys will work properly and have the proper balance.

3) To make things more complicated, I used the new water pump I had for the 1969 302 and put it on the 351W. The outlet on the original 351W water pump was on the driver's side and it is now on the pasenger side so it will match up to my new radiator. The pulleys are a concern again because of the water pump and/or the balancer/crank pulley issue noted in point #2.

I think these are the only issues I have run across so far. These may be easy issues to fix, but are frustrating nonetheless. I just thought I would add to the list of things that are or may be ran into when putting a 351W in place of a 302. I am open to suggestions as well.
:rlaugh: :rlaugh: :rlaugh: You're trying to "mix & match" too many parts here. Do as rbohm says, also stick with the 351W waterpump, The pass side and driver's side pumps use different timing covers. The bolt pattern for each is different and the timing pointer's are on different sides of the crank. You're going to end up with water leaking and it'll be damn near impossible to set the timing. Use all the accessories from one or the other, mixing them up just makes problems. The adapter bracket you need is a junkyard item. I had several of these awhile back but sold em all on ebay ($15-25 each:D ) You can find these bolted to the heads of 70's 302's and 351's. It's a cast aluminum or iron piece that's bolted to the head with 2 bolts and has 2 other threaded holes cast into it. Sorry, don't have a pic of one. :shrug: How's things in Lumberton ? I grew up in Silsbee, but moved out almost 30 years ago in 1977.