Thread: 406 C3AE-V Cross bolt???

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I have a 406 engine part number C3AE-V. This block has cross bolt mains and they look original. I know all the books say that its not a cross bolt block but is that entirely true? I know Ford did some weird stuff back in the day. Any help would be appreciated. Thanks!!!

Never have heard of one, but that certainly doesn't mean that one didn't sneak out the back door at Ford once upon a time.... Next time you're among the old Ford parts guys, I sure would like to find one of the old 4V Autolite inline 4V carb and intake setups sometime....and not have to rob more then a couple banks to own it..

FFR should be around sometime, hopefully he can shed some light on what your block might be.

The only true crossbolted 406 block I've seen has been a C2AE-BD block. It was rumored a NASCAR block back from the day. This was back in the late 70's. I've had both the C3-D and V blocks and both were cast with the crossbolt bosses but had 2 bolt maincaps from the factory. The maincaps were both C2AE caps and grey iron not nodular like the C3AE 427 caps. Anything is possible and it's not the first I've heard of owners finding crossbolts in their 406's. Have you checked the cyl wallcores to see if it has 427 cores? STD 406 cyl wallcores can fit a 13/64" drill bit shank between them. My C3-D block had one side cast with 427 wallcores and a 7/64" bit shank a snug fit. Weird but true and some do have 427 cyl walls. The 406 was a "tweener" engine. Developed from the 390HP and the precurser to the 427. The 406 is not only very rare but interesting as it was the test mule for the development of the 427. The only way to see if the block is an original crossbolt block is to measure the mains to see if they have been line bored. You need to line bore the block when you install new maincaps. This will tell you the real story. If the engine is built and running enjoy it till it needs a rebuild. Then you can get to the bottom of things. But if the engine is out and apart check those mains!!! Very cool engine and thanks for posting. The 406 is one of my favorite engines. Let us know what you find.


G.

I'll have to check out the block a little more closely. The engine is out of the car and apart so I can get a better look at it. It still has the crankshaft in it and is a C4AE-B 427 crankshaft. The motor was definately rebuilt at one time and used in a Cobra. I received it with a snapped rod! Other than the obvious, are there any tell tale signs of align boring that are easy to spot in the FE's. I really appreciate the help here in this forum. Thanks!!!

Normally .001-.002 of material is removed when the block is align bored. Offhand i can't remember the exact measurement of the mainsaddle bores. Both 406's i had used a grooved crank on the mains and were C2 and C3 castings. But it's hard to tell if that's the original crank. It may or may not be. You might be able to tell from the timing set as align boring brings the cranks centerline a little closer to the cam. In some cases a shorter timing chain is used. You can inspect the main area and see if it's looks like it's been machined. Original blocks would have a patina on the main face area. Best thing is maybe bring the block to a good shop and have them measured. I'm sure they can tell. It's hard to say otherwise without seeing the block in person. Either way it's a really nice block to have. What heads are on it?

G.

Thanks for the help FFR! The block came without any heads on it. They were used on the new engine put in the car so I never saw them. Upon close inspection at the crossbolt areas on the side of the block they all have that little recess around the bolts like the factory cast them. I really think this thing is an original crossbolt engine unless, someone went to the pains of replicating those recesses. This thing must be one of Fords factory mistakes, or actually bonuses! I do want to check the core though to see what it is. I guess I shouldn't be looking a gift horse in the mouth since I got the block for free but, its nice to find out what I have. Yeah, I got it for free from someone who was going to throw it out as scrap. I guess even a blind squirrel finds a nut every once in a while Thanks again for all the help!!

The recess you see are the crossbolt bosses. Some of the 406's have em and some not. But the crossbolt mains could be original who knows??? Holman Moody did build quite a few 406's for NASCAR and boat racing back in the day so it could be original. Being the 406 was the test mule for crossbolted mains and the 427 casting anything is possible. Books can't dictate what went out the back door...and lots of stuff did. Hard to say. But for free??? Dang bud good deal there!!! Keep us posted and if and when you drill bit the cyls let me know what you find. There were less than 1000 406 cars produced. So there are not many left. And your block is a keeper and very rare. At best maybe half or less of those survived.

G.

Yep - there were some 406 engines built that had cross bolted mains - I had a late '63 XL 2 dr hardtop. The whole engine was a mish mash of strange parts, that included the mains plus 427 long style headers. These were not someone elses add-ons because I bought the car new. Unfortunately, in my infinite wisdom I traded the car for a new '65XL w/390/330 solid lifter interceptor engine - what a big disappointment after the 406 - that entire car was a Monday built piece of junk.