I'm hearing a lot about this larger bell and small bell stuff when referring to a C4 trans, especially when it comes to doing a V8 swap...what exactly are you techs referring to when larger bell or small bell is mentioned? *I myself have a 250, inline 6.*
144-170-200 i6's use a small bell housing. the 250 I6 uses a v8 bell housing though so you can bolt a 302 up to a 250's trans
It is referring to the number of teeth the flexplate has mainly. A 164 tooth flexplate requires a larger bell housing then a 157 tooth. 250's use the SBF small bell housing with a 157 tooth 0 balance flexplate. The bell housing will work with a V8, but the flex plate will not despite the fact that it will physically bolt up to a SBF. It has nothing to do with 144-200 6 cylinder engines. They have totally diffrent bell housing paterns and are a completely diffrent animal when it comes to bell housings, flex plates and torque converters.
So Jamie Miles what I'm understanding from you is that since I have this 250 motor with a automatic C4 trans it has a small bell housing; but to do the V8 swap I would need a bigger flex plate to accommodate the different motor, correct?
No ... a Maverick 250 or 302 uses a 157T bellhousing ... that is considered the "SMALL" one ... Some Ford cars used a 164T bellhousing .. that is the "BIG" one .. You do need a different flexplate to account for the different engine imbalance though ... 0 ounce imbalance on the 250 and 28 ounce imbalance on the 302.
As dmhines said, if you're swapping a 250 to a 302, you'll need the proper 302 flexplate. The 250 flexplate does not have an external weight on it, which means it'll vibrate just a little. All 302's are external balance unless the machine shop that balanced it added mallory metal and set it up as an internal balance (which usually costs quite a bit more $$$). Then to confuse things a little more, 302's could be had in either the early balance factor (as dmhines referred to as the 28 oz) or the late (50 oz) balance. The late ones started showing up around 1982, more or less.
