Thought I had a 390 but now I'm not 100% sure.. every 360 or 390 I've seen has a 352 stamp on the front of the block on driver side. This block is stamped 105 backwards. Any ideas?

 

That is a block from early 70's up to end of production in 76, either 360 or 390. If it has 3 vertical ribs cast on side of block, it is probably a service block, that was sold over the counter

 

Ok thanks just getting ready to rebuild it wanna make sure I didn't goof up and buy the wrong kit

 

The reverse image replaced the long used 352 block. It has a bit more webbing in the bottom and considered a better block by some. Those blocks came with the heads with hardened valve seats, if memory serves.

It could be either a 360 or 390 and you will have to check the stroke to know fo sho. These were used in trucks and aftermarket.



John

 

Was told by the builder when I got the truck it was a 390

 

Just sayin, Most FE 352s & 360s magically become 390s on sale day. Not trying to say that your's is not a 390. A stroke check is the only to know for sure.


John

 

At the risk of asking a loaded question...how do you check the stroke?

 

set the crankshaft to Top Dead Center, with pointer at 0deg
pull plug number 1 and 4 (no 1 will be at the top of the cylinder and no 4 will be at the bottom)
take a skewer of wood or something thin and put it down the holes parallel to the cylinder wall until you touch the piston
mark the skewer on both cylinders at some point that will be equal on each cylinder (at the valve cover is my suggestion)
the difference between the two marks will be the stroke measurement

360= 4.05" bore x 3.5" stroke
390= 4.05" bore x 3.784"

that will get you close enough

 

I just use the No. 1 cylinder and measure how far up and down it goes.