While looking around on this subject, I ran across a few threads on Lonestarspeedzone.com, JalopyJournal and The H.A.M.B. about Meyer Speedway, the Modifieds and the #7 Blumrick car in question. Since I never visited that track, what I can gather from the posters information is the cubic inch limit was for the Pony class just under the Modifieds. As far back as 1963 there was talk of 427's , 406's and 428's being used in the mods. One poster mentioned a couple of times about the #7 car using a pontiac engine. In the video MarkJ posted the announcers tell you the car chasing Blumrick is running a big 427 and the 7 car has a 327 with 3 2bbl carbs. I have no idea what types of engines the #7 car may have used during its life but in the 1963 press photo I am convinced what I see is a poncho head. In the second photo the valve cover above the second man from the lefts head is too long to be a SBC to my eye but photos can fool you. So, what you have started MarkJ is a history mystery. You are in Texas old son so do some detective work and find some answers for us. If I found this much, you should be able to find more.