Need a reminder, two versions of the small block flexplate 156 and 164 tooth. I have a large bell housing C4 truck transmission with the 164 tooth plate behind a 5.0. I'm sure the 157 tooth plate will work with this transmission but will the starter bolt up? I'm thinking no?
The flexplate and bell housing have to match. Starter mounts on the bell housing and it will only meet the ring gear if they are matched. Large bell housing needs the 164 tooth flexplate.
Thanks JS, one more question, can large and small bellhousings be switched on any C4? Need to know if I can go with a small bellhousing on the truck C4.
Think so. Someone will correct me if that's not right. You'll need the smaller spacer plate too. Not sure if the torque converters are the same.
I know I can purchase flex plates with dual bolt patterns for the converters. Not sure about the spacer plate. The bolt pattern would be the same so not sure I need to change the plate. Also, does anyone know if the AOD and large C4 bellhousings are the "same" size? I think they use the same size flexplate.
There are at least two different styles of C4 bell attachments. Not sure if they're interchangeable though.Then there's the dipstick to deal with. The big bell C-4's have a "pan fill" dipstick, whereas the 157's have the dipstick going into the case behind the bell.
The holes for the starter gotta be in a different position. When you get it all sorted out it would make a good tech article.
I know some AOD and big bell C4's share a common flexplate and torque converter bolt pattern. My 85 engine had an AOD behind it, I used a big bell C4 out of a 77 Granada, it bolted right up. I think, but not sure, all small bell C4's bolt the bell to the pump housing,all large bell bolts in another set of holes outside the pump housing. I'm not sure if there is a large bell that bolts to the pump hosing like a small bell, but there might be.....
You can put the 157 tooth bell on the truck C4 that has the 164 tooth bell with the seperate 5 bolt pattern..... You will need the longer pump bolts that hold the 157 tooth bell on, you will also need a torque converter for a 157 tooth bell because the truck 164 tooth bell are approx .400 longer and have a longer torque converter which will not fit in the 157 tooth bell housing..... So if you want to change to 157 tooth you will need the bell housing, bell housing retaining bolts, block plate, flywheel and torque converter.....
The 157 is quite a bit smaller then the truck 164..... I know the truck 164 is pretty tight in a 70 tunnel, but there is plenty of room in the 71 up's..... In either tunnel it will have quite a bit more air space around the bell with the 157 though.....
The difference in diameter of the 157 vs the 164 tooth flexplates/flywheels is one inch. So you can expect to gain a half inch per side on the bell housing, irregardless of the casting differences. Then there's the C5 bell which is 1 inch longer than the C-4 bell, with a pronounced bulge on top and rearward to accomodate the deeper/thicker torque converter. The C5 bell is a 164 tooth unit too.
