In Boswell's London Journal (1762-3), the author expresses the past tense of the verb eat with the same spelling:
I sat in till between four and five. I then went to Holborn, to a cheesemonger's, and bought a piece of 3 lb. 10 oz., which cost me 14 1/2d. I eat part of it in the shop, with a halfpenny roll, two of which I had bought at a baker's. [emphasis mine]
This makes me wonder at the pronunciation, as I have wondered before. When I first read the journals back in college, I mentally pronounced them the way we say the current present tense verb. Then I decided he must have pronounced it /ˈeɪt/ rhyming it with ate. So far so good.
Now I wonder if the word might have been pronounced /ˈɛt/ (rhyming with bet) the way some British and rural Americans have it.
The word eat itself comes from OE etan by way of ME eten, which would suggest that it might have at least for some time rhymed with ate.
Note too the past tense of some verbs are identical in spelling to the present tense (e.g., read/read), though pronounced differently.
Can someone cast a bit of light on this?