I am looking to clarify the 351C's cylinder heads . I thought I had 351M / 400 heads on a 400 engine block . Finally double checking I see the " 2 '' script in the corners ? 2 and 4 script heads were only used on 351 Cleveland engines , right ? So the block these heads came off should be pure 351 C

 

351c 2v heads are the same on 351m and 400 engine. no 351m or 400 were built with 351c 4v heads from the factory. it dosent mean they didnt fit. same bolt pattern.
he have 4 or 5 kind of heads you can bolt on a 351c. from 70-74 351c US ford produce 4 kind. in australia they produce a mix from 4v and 2 v heads. not available in US. they call them aussie heads. australian took the closed head chamber design from the 4v US and cast them with the intake and exhaust design from the 2v US heads. if you have a 351c with 2v heads its not rare. same as 351m/400.

 

do you have a casting # ? i have all the casting #. not in hand now but someone have it on this forum. some years have different cc's chamber and valves sizes.

 

tried to find build casting ##'s ,are non I can see on the heads other than a short 4B27 one head and the other has possible 3F12 , that ones hard to read . These heads were removed off the possible 351c block that is still in a old ranchero . They weren't cc checked but are going to be . Suspect there in the 70cc range being from a 1974 year car .

What I have read is 351M ' and 400's didn't come with 2 or 4 bbl script heads . Not saying they wont work on the 400 . I will be surprised if that old rust bucket had a Cleveland .

 

You have Cleveland heads, 2v, open chamber. If there's no little raised circular "bump" next to the 2 then they are closed chamber 2v heads. Those heads will help raise the compression ratio.....trouble these days with the junk fuel we have. Still, they're desirable heads. A 'bump' beside the 2 means they're open chamber heads.

351M/400 heads would have an 'M' stamped in the upper corner. The vast majority of M Block heads have this although a few don't have any markings.

Cleveland heads could have a 2 or a 4 stamp, with or without the raised half moon "bump."

 

no bump beside the 2 , been dickering around looking for a Cleveland to replace a Windsor and find I have one right under my nose . Was a short paragraph about the only trucks that came from the factory with 351c's were rancheros , 1970 - 74 that caught my attention .

 

The 2 barrel heads are all pretty much the same. The numbers you found are casting dates the 4 is 1974 the B is the month and the 27 is the day. So you have one head cast in 74 and one cast in 73. The good thing is Ford started induction hardening the valve seats in 1972 so your heads should have hardened seats. The bad thing is sometimes they crack so have them checked before you use them. These pictures show the engineering numbers cast in the bottom side of the intake runners. The first one is a 4V Cobra Jet head form a 351C, 1973 Mustang. The other is a 2V head from a 351M or 400 I can't remember. The last pic show the difference in the port size. You might notice the 4V heads don't have the big valves for some reason Ford used the smaller 2V size valves in them.

 

the only place I didn't look was under the head . My heads have been reconditioned .

 

The first time the seats are ground that factory hardening is gone. Ford did not put an actual hardened seat in. The good thing about the C head is it has a better exhaust port, no smog.

 

how about aussie head?

 

No thermactor on the Aussie head either. Same with the 1971-74 400 heads, which although they have different casting numbers, are essentially identical to 351C-2V heads. George Pence said that the Aussie heads don't flow as well as the other 2V heads. With decent pistons from TMI, I don't see the big advantage to Aussie heads anymore.

 

Not true. If that were the case every single cast iron Ford head would require seat inserts when it was reconditioned. The factory hardening is plenty deep enough to support at least one regrind without going through. But on the other hand if what you say is true that would prove conclusively
that seat inserts are totally unnecessary, because 90% of the heads that are reconditioned don't get seat inserts. The heads in the picture with the layout dye on them got exhaust inserts, not because of the hard surface being ground through but because three of the eight had cracks in them.

 

I have ground tons of them over the years and they are anything but hard. However one rarely comes across a broken seat. I would put seats in if I was going to run any real spring psi though.

 

D1AE CB is the casting ##'s on these .

 

1971 cylinder heads - could be off an early 400 since it was first introduced in 71. It's an early 2V Cleveland head at any rate. What year is the block?