switching from a 1977 351w to a 1968 302. had a 164 flexplate on the 351 with a c-4. i'm assuming that i need to switch to a 157 tooth flexplate. what determines which plate you need?
Hey Don, I think the main thing that determines what flexplate you need is the bellhousing. If the bellhousing you have on your 351 bolts up to the 302, then I think you should be able to keep that set up. If you have to change the bellhousing (to the smaller orig 302 one), then you need to go with the 157 tooth flexplate. If you have to go that way, make sure to change the starter to one for a 157 tooth plate, as it wouldn't mesh perfectly with the starter you are using now. Keep in mind I don't know if the bellhousings on the 351 bolt up to 302s. I don't think they do, but I am sure someone else can verify this for you. The 164 tooth flexplate works with the 302 (AODs), but like I said before the thing you have to figure out is which flexplate will fit in the bellhousing that bolts to your particular engine. -Corbin
Flexplates It has been my exsperience to use either the 157 or 164, they both bolt up to the small blocks. The big decision is which converter bolt pattern you have or want to use and the corrosponding bellhousing. On case fill C4's where the bell bolts to the pump you can interchange either bells to match, I use the small one and 157 flexplate with 10.5 converter bolt pattern. Have also found the same starter works on either one because the mounting position is in the same relationship to the ring gear on each one. Most pan fill trans have the bell bolted to the case and are said to be a bit more durable but that is up to each persons opinion, there are many C4's case fill that have the 5 disc drums in them, the 26 spline input shaft is the way to go, it is larger in diameter than the 24. All in all consider the bolt pattern, and converter you want, the rest can all be matched and interchanged as you wish, and yes the bell will bolt up to all small blocks with exception of the early 289.
Don's Dilema To make this simple Don, take the flexplate off your 351 and bolt it on the 302. Take the c4 you also removed from the 351 and converter then bolt it on to the 302. Job is done. If for some reason you should want to use a 157 then you will have to use the small bellhousing and appropriate converter bolt pattern ie. 10.5in or 11.7/16. I can give you the part # of the small and large bell if you need it. I may have confused you with my previous post.
You can use either the 157 or the 164. You need the matching bellhousing for either one. Why would you use one over the other? For the most part, which torque converter you will be using...each flywheel has a different torque converter that will match up to it. You might want to just stick to what you got! I guess if you wanted to get into physics, you could look at the slightly smaller one as an off-the-line advantage (less rotational mass, easier to start spinning) and the larger as a top-end advantage (more rotational mass...wants to keep spinning). I doubt you'd notice much of a difference on either...
thanks guys for the info. after thinking it over in the daytime i figured that i'm using the same tranny and the 351 and the 302 are the same bolt pattern therefore i should just stay with the same flexplate. i am going to a hi torque mini starter also. talk to you all later.
