390 Ribbed block

[preaction]

Was a 390 ribbed block made ? I came across a Ford remanufactured engine with a rivited tag and a C3AZ part number installed in a 66 Tbird with bearing and bore info stamped on the tag it is a ribbed block it has a date but the year is not readable and I cant find a  block casting number it came with a D0 stamped starter any ideas ?

[Katz427]

 The local Ford rebuilder, shop was about 5 miles away. According  to a machinist  who worked there,  engines were rebuilt with whatever blocks were available. So if a person needed an engine for a 1963, a 390 block was selected ( any year available) ,  pistons, and rods, and a camshaft similar to the stock specs. IF a shortblock, that was what you got, if complete with cylinder heads, any pair of 8 bolt exhaust, cylinder heads available, were used. 
So even if the tag reads C3... , the block could be whatever 390 block that was available  for rebuild at that time. The machinist  said they were not worried about numbers matching.

[frnkeore]

What is the casting date code, under the oil filter adapter?

[Rory428]

Yes, ribbed 360 are quite common, virtually every 360 or 390 block cast after about 1971 has the ribs.

[preaction]

This rebuilder was in Oklahoma city, Oklahoma. The year number was slightly ground on and unreadable. It was a fancy tag aluminum with two drilled holes in the block and two fastners like the ones used on the underside of a FE intake to hold the oil splash pan on. We removed  the fastners to remove the tag and oil was coming out of the holes at a very fast rate. This was on the passenger side of the block.

[thatdarncat]

Like Rory said, the blocks with the external “ribs” were just FE/FT blocks cast at the Dearborn Iron Foundry (DIF) starting in early 1971, and the ribs continued through the end of DIF FE/FT production sometime in 1974. ALL the FE/FT blocks cast at DIF during that time period had the ribs. The Dearborn Iron Foundry quit putting casting numbers on the blocks starting during the 1969 model year, so it’s also not unusual for the block not to have a casting number. They do still have a casting date code under the oil filter adapter pad, but as you found sometimes they aren’t readable. You should find the DIF logo on the side.