I agree with Bill the T-bolts had the 427 HR with 8V (2-4). After the 63 1/2 Galaxies were introduced and got the first 427 8V low rise and high rise engines they were available in the other galaxy models. Early 63's had 406's 4V and I think 3-2's. The R designation was in that years serial number to designate the 427 8V. I think the 427 4V was a Q engine. I had a 63 1/2 Galaxy XL with the R engine. I think ford kept those codes for a few years at least. I had the pleasure of watching Larson Ford race the TBolt at Dover drag strip in NY. It was quite a car. I ran in the low 12s with mine it was a Holman Moody blue print with not so stock a cam. More info on Gessford Machines web site
http://www.gessford.com/images/FordMuscleStory.htm
Some info from that page I quote “All 427 blocks are cast from high strength alloy iron with a 4.23 bore. Most 1963 64 blocks were identical to the 390 high-performance and many 406 blocks in that they had beefy lower end webbing, 2 bolt main caps, large
oil galleries and a preasure relief valve near the rear top center. Some 63-64 blocks used “cross bolt mains” ussualy 427-8v low riser and all 427 high riser engines. All 65-66-67 blocks were side oilers, just like the 427 SOHC, and used cross bolt mains. The side oiler was also used in 1968, but
oil galleries to the lifters because this engine used a hydraulic cam.”