C5AE 390 block cast with cross bolt bosses

[Urgefor]

As noted in this post, apparently C5AE 390 blocks were cast with crossbolt bosses similar to the '64 blocks.  I haven't had much luck determining if it is all C5AE blocks or just some.  If anyone knows the answer to this, I am all ears.     Thanks in advance.

[thatdarncat]

As noted in this post, apparently C5AE 390 blocks were cast with crossbolt bosses similar to the '64 blocks.  I haven't had much luck determining if it is all C5AE blocks or just some.  If anyone knows the answer to this, I am all ears.     Thanks in advance.

From what I’ve observed, it’s definitely not all C5AE-A blocks, only some. Certainly no where near as common as the ‘64 model year blocks. They might be the second most likely garden variety FE/FT block to have the cross bolt provisions though, from what I’ve seen. I try to watch & log casting date codes and other block characteristics I see, both in person and on the internet, but unfortunately not many people post all the details of their blocks, so I don’t have any definitive patterns yet. There were also two different & distinctive formats of how the “C5AE-A” block engineering number on the side of the block “looks”, but again no idea if there is any correlation between the “style” of engineering number and whether it might have the cross bolt provisions. Hopefully maybe some people will post up what they’ve found.

[63ragtop]

I have a C5ae-a 391 FT no bosses.

[Urgefor]

I'm running with the assumption that early model year blocks would have a better chance to be cast with the bosses.  What I don't know is what would be considered "early"?  September to January?  September to April?

[frnkeore]

I'm running with the assumption that early model year blocks would have a better chance to be cast with the bosses.  What I don't know is what would be considered "early"?  September to January?  September to April?

Does it have any markings or scratch marks on the rear of the block?

I'm very interested in the first 2 years of the FT, '64 & '65.

[thatdarncat]

I'm running with the assumption that early model year blocks would have a better chance to be cast with the bosses.  What I don't know is what would be considered "early"?  September to January?  September to April?

“Early” would be at least June 1964. I have the date codes logged for multiple C5AE-A blocks with mid June 1964 casting dates. So figure the summer months for “Early”.

From what I’ve seen that’s pretty typical that new model year blocks tend to start to be cast at least by June.

[Urgefor]

Does it have any markings or scratch marks on the rear of the block?

I'm very interested in the first 2 years of the FT, '64 & '65.

I don't have and have not seen one of these blocks so I have no idea. Richard(FERoadster) replied to a WTB post I started in the Private Classifieds forum.  I will ask if he can chime in or post some pictures.

[MeanGene]

The main reason for the new C5AE casting number was the change in the casting to the 4-bolt mount flange

[frnkeore]

I have a C5ae-a 391 FT no bosses.

Sorry, Urgefor, I hit the wrong Quote Icon.

I meant to ask 63ragtop about the '65 FT 391, block.

[Mr Woodys Garage]

My Early 1966 428 "S" Scratch Was Cast with 4 Bolt Provisions, But, Of Course, Not Machined. I Went With The Full Perimeter 3/8" Girdle Instead Of Having The Block Finished Out For Standard 4 Bolt Caps On The Center 3 Main Bearings. It Was a Lot Of work, Was Done Very Professionally, And At Least In My Opinion, Is Superior In Strength. I will Check My Photos, And See If I Can Get A Date Code. My Understanding Is That They Were Cast From October 1966 Till February 1967. Again, Just Because I Found/Had One Doesn"t Mean They Were All Cast That Way. Seems From Prior Feedback From Other Enthusiasts, They Were Quite Rare. (Yes, This Is A 428 Block. We Installed Screw In Core Plugs, And The Obvious Roller Style Cam Bearings)

[Gregwill16]

I think you are off a year on your S scratch 428 block dates. They were supposedly built late 66 and into early 67 calendar year.

Here is a 6M S scratch that was recently advertised on eBay.
https://ebay.us/m/rJ8lIU

[frnkeore]

Regarding the Ebay block, I must note that the block may have started out as a FT, since it has a tapped oil return hole, for a compressor. It would need to be checked for a bushing in the dist hole.

[Mr Woodys Garage]

Yes, I Was Off By A Year. (Age And Radiation Does Mean Things To A Guy.)
  I Modified My Response Above To Keep Information Correct. Nothing Worse (Almost) Than Faulty Information Being Shared As Fact.

[My427stang]

Urgefor,

Do you need the C5 and/or the bosses for a specific reason?  As I understood you were using aftermarket caps.  They are wide to allow direct contact without the bosses if that is attractive to you.

I do have a C6 block in Nebraska, std bore, pressure checked, but not cleaned or magged.  Not chasing a sale, stock for later incoming builds, but if it helped you out of a bind I'd be happy to flip

[frnkeore]

Ross, does that block have a oil return in the skirt?