Socnarftrucks Posted January 29, 2021 Share Posted January 29, 2021 Installed a new 4.9L with a rebuilt C-6 AT transmission on my 1980 f100. Have a significant vibration. How can I tell by looking through the inspection window if I received/installed the right flywheel for this motor and not for a V8302? Link to comment Share on other sites More sharing options...
Rembrant Posted January 29, 2021 Share Posted January 29, 2021 If you look on a site like RockAuto you can look at pictures of each flex plate to see the difference between them. Basically they will be the same except the 302 flywheel will have a balance weight welded to it. I think it is on the inside or engine side. Link to comment Share on other sites More sharing options...
Socnarftrucks Posted January 29, 2021 Author Share Posted January 29, 2021 If you look on a site like RockAuto you can look at pictures of each flex plate to see the difference between them. Basically they will be the same except the 302 flywheel will have a balance weight welded to it. I think it is on the inside or engine side. Link to comment Share on other sites More sharing options...
Socnarftrucks Posted January 29, 2021 Author Share Posted January 29, 2021 This is what I got from the transmission shop. Looks like a 302 or 351 Link to comment Share on other sites More sharing options...
Rembrant Posted January 29, 2021 Share Posted January 29, 2021 This is what I got from the transmission shop. Looks like a 302 or 351 I would say so, yes. And it will cause a 300 to vibrate for sure. A 300 flexplate should not have weights welded to it like the 302 or 351 flexplates. I would say by the size of the weight on yours it is for a 351 or earlier (pre-1982) 302. 351 Flexplate: 302 Flexplate: 300 Flexplate: Link to comment Share on other sites More sharing options...
myrl883 Posted February 7, 2021 Share Posted February 7, 2021 This is what I got from the transmission shop. Looks like a 302 or 351 I would say so, yes. And it will cause a 300 to vibrate for sure. A 300 flexplate should not have weights welded to it like the 302 or 351 flexplates. I would say by the size of the weight on yours it is for a 351 or earlier (pre-1982) 302. 351 Flexplate: 302 Flexplate: 300 Flexplate: Size is exactly the same, V8 engines use weights, 6 cylinders do not. You can cut the weight off and you'll be good to go! Link to comment Share on other sites More sharing options...
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