Engine ID year

[GenLee1970]

The /6 engine in my 73 Swinger is not original to the car as the vin doesn't match. The guy I bought it from said it was a 71 engine. It doesn't really matter in the long run, but I'd like to know. I googled it and read a few articles and posts on dating the motor but they didn't really help. The numbers on the block near the alternator are GW 225 R 3553.

I know G was the series code for 71, but what about the W? I thought "warranty" but it has a vin stamped in the correct location. And the R? Raised block? 3553?

Anyone know off hand?

 

[Alaskan_TA]

W= Windsor Ontario engine assembly plant.

R - Regular fuel recommended.

3553 - Engine final assembly date from the 10,000 day calendar - April 20th, 1971.

Are there 4 more digits aft the date?

 

[GenLee1970]

No, no other numbers that I could see.

Thanks for all the other info O

Al