Never seen this casting before....396021Fa....GST?...and for your viewing pleasure it is upside down....again

 

Ted, it's from the late 72 - 76 model years. There were F blocks that had overlap dates (68-74). Does that help? BTW, where did you get it?

Edit: Not GST. It looks more like 08 T. T is an engine code used with the 455. I'd guess that 08 is either the mold number, or the production month.

 

Thanks Allan.....I must have GST on the brain��...the seller thru it in with the 71 4 speed deal....want it?

 

What is an overlap date?

 

Sure, but it would cost a fortune to ship here. BTW, GST didn't arrive as a gift from the Gubment till Jan 1, 91 so anyone who thought of GST that far back must have also won countless lotteries

The G was produced from 68-74. GA from 72-76. The overlap of G/GA production was 72-74.

 

Just an afterthought Ted,
Look at the heads on that 455. If they're GA, it's a 72. If they're J then it's 73-76. Also look to see if it has an EGR application on the drivers side of the intake manifold. That appeared in 1973 also.

 

The VIN derivative stamp on the block will tell you the year of the block. Everything else bolts on and can be changed over the last half-century.

 

Well...YEAH! That's what I meant..... But if he wanted to know whether the intake and heads were 72 or later.....my way works too.