I have been looking for a date correct 1971 block for my SPD April 30th 1971 Cuda. My buddy from Pennsylvania sent me pictures today of a 1971 block that he has... the casting number was definitely in the ball park for a Mounds Rd engine including hints of the Corporate Blue paint but when I asked him for the numbers under the numbers below the #1 cylinder, this is what he sent me. Can anyone here help me decode the Two lines, it looks like the first line has light stamped 3,6,8's or 0 and then a 2 on the first line and the second line reads MH 340 R (Regular Fuel) or P (premium Fuel)I believe, MH could be M=Mounds Rd and the H would be 1972 assembly but usually the year proceeds the plant from my experience, like GM for 71 Mounds Rd or FW for 1970 Windsor. The last Picture is the current May 1st 1970 engine I currently have for the car which looks nothing like his block numbers.

Looks like a 1972 engine, what is the VIN# stamping on it? Your 71 should have an assembly number starting with GM340 (1971 Mound Road) or GW340 (1971 Windsor). Being a later SPD it was most likely a GM340

Scott,
I'll have to get the Vin from him. I assumed its a 72 built engine but the January 1971 casting date thru me off along with the multiple stampings and dual lines. I'm trying to find a date correct block for my 71' April 30 build just coming up short everywhere. You built me the correct carb and I also have the correct exhaust manifolds, distributor, alternator..ect

Yea, the Mound Road blocks seem to be fewer and further between, I've seen 10 GW blocks for every GM I've seen. Casting dates to build dates varied a bunch, most were 2 weeks to a couple months a part but there were much bigger gaps sometimes so you never know.

what is the order # on your fender tag?

430 E35280

Since I am looking for a date correct block would it be to far off to use since it's a January 1971 Mounds Rd casting. Once painted all that would be visible is the casting date not the final assembly date. I would like to build a date correct 340 with lighter forged pistons and connecting rods and since the heads are X heads I'm looking to build a set of "J" heads which would be correct for the 71' year build. I have a great running May 1st, 1970 engine and I am not looking forward to spending more money for changes that the majority of people will never even notice but I feel the car is worth the effort .

My Hamtramck 1971 Duster 340 engine has a date of 1-19-71 on it and is Corporate Blue. The car has a SPD of 07/09.

I have a late 71 block with a 71 VIN, standard bore. Never was sure of the application or assembly date, or if it was A or E-body.

VIN: 1B4525**

1-27-71 cast date.

3528 = March 26, 1971. Most cars had assembly dated engines closer to the SPD of the car but there are no solid rules on that. So, as a replacement it would be fine for your car.

That is interesting and makes sense. My 1-19-71 block is matching numbers and my VIN: 1B452494