Good point, the dimensions are from Summit Racing and are given as overall, so it should physically fit in. Of course it would be undersized some and like you said the flow would be pretty fast.
As for attachment, perhaps I could use some wire to connect it to the existing baffle, then seal around it with high heat tape. Or maybe it would need a sheetmetal adapter of some sort. Hopefully not, as that might be more effort than the $$ to redo it properly.
Side note, the outlets of this are 6AN which is 3/8", so it will need inline adapters to go to the 5/8" Packard heater hose.
https://www.amazon.com/Beduan-Reducer-Reducing-Fitting-Splicer/dp/B08V4Y89VD/This Post was from: https://packardinfo.com/xoops/html/modules/newbb/viewtopic.php?post_id=272443