Griffen Metamic B4C Track

Found this in One Facebook Marketplace in L.A. and the seller would not ship. Thankfully a homie in L.A. copped it and shipped it to me! Just waiting on a Wound Up Zephyr, a 19t cog and maybe some crabon headset spacers. The seat tube appears to take a wonky size post, perhaps a 28.6? I have it shimmed with a 27.2 post and it seems to be snug as a bug in a rug. It seems to be a bit of a pursuit geometry but its sizing up to be about 54-55cm which is perfect for me!