FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: Urgefor on October 21, 2025, 07:11:24 PM
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As noted in this post (https://fepower.net/simplemachinesforum/index.php?topic=12292.0), 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.
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As noted in this post (https://fepower.net/simplemachinesforum/index.php?topic=12292.0), 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.
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I have a C5ae-a 391 FT no bosses.
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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?
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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.
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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.
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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.
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The main reason for the new C5AE casting number was the change in the casting to the 4-bolt mount flange
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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.
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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)
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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
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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.
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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.
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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
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Ross, does that block have a oil return in the skirt?
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Frank just an upside down 352 on the bulkhead, a 5c10 date a real small c5ae-a
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Urgefor,
Do you need the C5 and/or the bosses for a specific reason?
Mostly to make my life a bit easier. I have a '64 block with the bosses but the project car is a '66. I've fabricated some motor mounts to make it fit but it just "bugs" me a bit. Long story short, I was not aware some C5 blocks were cast like that also. If I can get a C5 block with bosses and extra material in the webs like the '64 block along with the 4 bolt engine mount pattern, it would be a win/win for me. I have a couple C6 engines. To be more precise, one engine (from a country squire) along with a complete drivetrain from a '66 Galaxie that was a real man's car. 4bbl, 4spd, no air, no power brakes and no power steering. :o
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Ross, does that block have a oil return in the skirt?
It does not
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i have a nice std bore c5ae-a block with bosses and thick main webbing
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i have a nice std bore c5ae-a block with bosses and thick main webbing
By chance have you seen this post (https://fepower.net/simplemachinesforum/index.php?topic=12941.0) in private classifieds?
For historical purposes, what is the casting date on your block? Also, it sounds like Kevin would be interested in a picture of the C5AE-A casting on the block for information gathering he has been doing.
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FERoadster here (now). Just got home this evening.
I was in Parker Colorado (near Elizabeth Co.) for the past 2 weeks and saw your message but couldn't reply because I didn't have my password. Message did go to my cell phone.
I will get photos tomorrow of each side, the front and rear bulkheads and the date code, I will also take a photo of the cross-bolt bosses and crow's feet area.
I'll post them on this thread.
Richard >>> FERoadster
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Pictures attached.
Block has a date of 1964 and day of 9 but cannot tell the month. Would someone take a guess?
Block is C5AE-A and main saddle supports are the early style and not crow's feet (reinforced). It is a DIF block.
No other special info.
Richard >>> FERoadster
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Block has a date of 1964 and day of 9 but cannot tell the month. Would someone take a guess?
Thank you very much for the pictures Richard. The letter denoting the month looks like a G(July) to me.
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Your picture actually does show your block has the “crows feet” main webs.
(https://i.postimg.cc/k5Y4NqsD/IMG-9253.jpg) (https://postimg.cc/rdWMM6vL)
And my guess would be “G” for the month also. A “4 C” would likely be too early for a C5AE-A block, and no other letter used would have that shape.
*And I’ll just edit to add - there is also usually a stamped assembly/test date code, often on one of the corner ears of the block, or on the front, and that will often help confirm the casting date code. Most common FE engines were assembled anywhere from a few days to a couple weeks after the block was cast.
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I didn't realize there are 2 or 3 "crow's feet" styles (Thanks Kevin) Here are 2 other types I've got. Also, the D4TE block date.
The C5 block I said was an old style since there is a window in the main saddle support. Just realized that the window is caused by the cross-bolt boss.
I've got a 3rd type but couldn't get a good picture today.
Richard
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Forgive me for asking the same question again, but I think maybe I didn't do it well last time, or I am not understanding the issue.
If you are using Billet Speedworks caps, or an equivalent pan rail to pan rail cap, why not use any 4-bolt motor mount block? You'll be cutting back the bosses anyway unless you plan to narrow the caps, or narrow them and use spacers as well.
Some say locating off the pan rail is weaker, but depending on component weight, a 2 bolt main can swing 600 HP, 6000 rpm. The caps are located off the register not the cross bolt, so you are really only grounding harmonics and adding another plane of stability, so they really shouldn't be any twisting force. If this is going to be a bigger machine than that, I''d think the rest of the block is going to call uncle anyway
Seems like I'd pick almost any good 390 4-bolt block, make sure registers fit nice and tight on the parting line, light fit with the pan rail requiring maybe a little lube to slide in by hand for reference, and make the block choice and machining easy
Thoughts?
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No need for forgiveness. :) For me, this thread is mostly about information gathering. For example, prior to this thread, I was not aware that some 428 blocks cast in late '66/early '67 were cast with the bosses extra material in the web.
My 2 cents on the different block castings in relation to installing cross bolt caps in a nutshell. While it isn't required (as you have noted) to have a block with the cross bolt bosses to install the caps and benefit from them, for whatever reason those blocks were cast with the bosses and extra material (crows feet) in the webs. While not necessary by any means, it seems like a better base/foundation to start with if cross bolt caps are being added. This, of course, assumes availability. Sometimes you have no choice but to work with what is available.