At first I thought it was a 1963 327 with 69-70 heads but the HF on end is confusing that. This engine is for sale so I only have the info listed not the actual engine in hand. Front of block - 5103699 FII25HF Back of block - 3782870 Heads - 3927186
I'll wait for "squirrel" to jump in with the engine/head casting numbers, since he's so good at that. I'm curious about the accessory mounts on the from of the engine, on both sides of the engine (???). I am Butch/56sedandelivery. Looks like squirrel was typing when I was!
HF is listed here http://nastyz28.com/gm-chevy-codes/chevy-engine-codes-suffix-5.php as a 327ci 1965 300hp unit or a 1966 275hp engine. Given the block number, this is the best bet from the information available. HF suffix was also used in 1969 for a 350ci. This engine would not have the location for the road draft tube cast in to the block, but I wouldn't expect that block number for '69. 186 heads should be ~ 64cc but had the accessory holes. If the engine was a '66 275 that could explain why the heads have been swapped..
I had 3 windows open at once with Mortec, the original ad and the HAMB, so yes HF, good thing I added that screen shot. I thought the 4th number in was the year and the 186 head could be 1.94 or 2.02. Isn't there something that says what the block was in, I know I've found that in the past ?
F1125HF F means the engine was built in Flint. 11 is the month, 25 the day, HF is as mentioned above. So the engine would either be 25th Nov 1965 or 25th Nov 1966. The nastyz28 link says if its a 1965 its a 300hp vette unit, if 1966 275hp "full size", so would presume impala etc p***enger car. This is mostly irrelevant anyway, as its got swapped heads and I would have thought the bottom ends of both would be the same with only the heads being different between 275 and 300 units.
I'm coming up with a '65 model 300 hp, M/T Corvette (HF) built at the Flint plant on Nov. 25. The casting date would help to clarify the application. If it has a late '64 casting date, which I'm guessing does from the 5 at the beginning of the partial VIN, 5 being for 65 model year, it probably REALLY is a Vette engine! JMO
yeah, the fact that it has a partial VIN makes it somewhat likely that it's a 65 Vette engine. But the code was used for several different engines over the years, and knowing the casting date would be a good verification.
The fact that this block has an "870" casting number and a November ***embly date leads me to believe that this is an early '65 build date, coupled with the partial VIN, (11/25/64 perhaps) If it was an 11/25/65 build, for the '66 model year, it more than likely (not absolutely) would have a "180" casting number on the block, with a 6 at the beginning of the partial VIN, if there was a partial VIN at all. Although the same long block, HF for '65 was 300hp M/T Corvette vs. 275hp A.I.R. P***enger Car for the '66 model year. Same long block, just different carb's and intake manifold's.