Nevermore

Wonder if those tiny size jump starter can really apply on my 1967 Jaguar E-Type. Takes forever to get engine started and I wonder if portable jump starter can help. That thought came from an email talking about fanttik t8 apex jump start pack which I have never heard. Did look it up online https://fanttik.com/pages/t8-apex-overview ,the website looks neat tho. It says pretty much works on any Vehicle up to 8.5L gas and it works as a 65W fast charge power bank as well. Got flashlight on it and some other features. Is it worth to buy? I mean for a jump start pack it seems pretty small, does it really work?