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M-block cylinder heads info

  #1  
Old 08-13-2001, 01:50 PM
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M-block cylinder heads info

Hey Guys!

I'm doing some research now on M-block (351M/400) cylinder heads, and I thought I'd pass along what I've found out so far.

I always thought that all M-block heads were essentially the same, but I was puzzled by some cc measurements I did on some heads that didn't jibe with the numbers in the Tom Monroe book, and then I started looking into this further. It seems that there are many more variations than I thought, with different combustion chamber sizes, and possibly even differences in ports.

Based on what I'm finding out, it's important to use a matched set when you build an M-block, with the exact same casting numbers, foundry marks, and maybe even model year casting dates, so your compression will be even from side to side. Oddly, I've found what appear to be original, unmodified engines with mismatched heads from the factory!

All M-block cylinder head casting marks (casting number, date codes, and foundry mark) are on the top of the head. You can see them when you take off the valve cover.

The early 400 heads (D1AE-6060-A1C,A2C and D3AE-6060-G2B) used from '71-'74 all had 75.6cc combustion chambers. The D3AE-6060-G2B head was a mid-year changeover in MY 1973 and used through MY 1974.

The later heads (D5AE) were used on all 351Ms and 400s from MY 1975 until production ended in MY 1982. (All truck M-blocks came with the D5AE heads.) These heads had various chamber sizes from 74.5cc to 78.4cc. The Monroe book documents only the 78.4cc chamber size.

These are the D5AE head combustion chambers I know about so far:

D5AE-6060-AA 74.5cc (before 1977)
D5AE-6060-AA 76.9cc (1977-later CF heads)
D5AE-6060-AA 78.4 cc (1977-later MCC heads)
D5AE-6060-A2A 74.5cc
D5AE-6060-A3A 74.5cc

The ports on all the M-block heads look similar, but I haven't yet analyzed them for differences in volume or flow. I expect there will be some differences in the ports, maybe significant.

BubbaF250

1980 F250 4x4 Custom, 351M/NP435/NP208/D44HD-TTB/D60-FF/3.55s 6750 GVW, Rust & White.
 
  #2  
Old 08-13-2001, 02:27 PM
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M-block cylinder heads info

I'm gonna print that and put it in my book! I wasn't aware of the chanber differences but have seen ports that have a highly raised floor. Don't remember year but I suspect these would be later models and an attempt to speed up port flow to compensate for retarded cam timing etc. I always look for the 2v Clevelands. I think they are more nearly the same.

1977 Ford F-100
400m/c6/4:11/Gear Vender O.D.
Crane hydralic roller, forged, ported polished,Deamon,Edlebrock, yada, yada, yada
280,000 miles
Stock on the outside
modified/rebuilt everything

 
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Old 01-17-2002, 02:13 AM
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M-block cylinder heads info

 
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Old 02-07-2002, 10:29 PM
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M-block cylinder heads info

i think you will find out that the 1971-1974 400 heads are different. i also think the car engines will be different than the truck engines.
 
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Old 02-07-2002, 10:48 PM
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Post M-block cylinder heads info

GT40man,

From what I've seen, cars and trucks used the same cylinder heads. All M-block heads were originally designed for car applications.

The only M-block cast iron parts unique to trucks were the D7TE blocks, intake manifolds, right-side exhaust manifolds, and flywheels.

I recently acquired a 1971 400 with D1AE-A1C heads, but I haven't measured the chambers yet.

 
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Old 02-08-2002, 02:01 AM
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M-block cylinder heads info

after further review, aka reread your first post. i see you covered that.
 
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Old 10-04-2011, 02:20 PM
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Sorry guys. Been out of the loop for a while. I am planning a 400cid build for my 79 f250 4wd and I have come across some D1AE-A1C casting numbers. I would like to know if these interchange with the M-Block and would they be usefull for a low to mid range tork over the stock 79 heads that I already have? Not exactly sure about them or their value? I can always use some helpful knowledge
 
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Old 10-04-2011, 03:21 PM
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Originally Posted by 4x4RANGERRICK View Post
Sorry guys. Been out of the loop for a while. I am planning a 400cid build for my 79 f250 4wd and I have come across some D1AE-A1C casting numbers. I would like to know if these interchange with the M-Block and would they be usefull for a low to mid range tork over the stock 79 heads that I already have? Not exactly sure about them or their value? I can always use some helpful knowledge
You can bolt any 351C head onto a 351M/400. However, there is no intake manifold that will match up to the large port (4V) heads so you need to buy manifold spacers from Price Motorsports and then use a 351C manifold. There is no advantage in using the open chamber small port (2V) 351C heads over the 351M/400 except when you compare those to later model smog heads that have the EGR hump in the exhaust port. So, in your case, a set of early 351C 2V heads will flow a little better on the exhaust side but intake will still flow about the same.
 
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Old 10-04-2011, 03:57 PM
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Do you have any idea what would be more beneficial towards my delimna as to what heads I should look for to benefit my engine or do I have my stock heads worked on? I can scrape up a pair of 75 heads? Im knew to this as it is my first rebuild and I want to do it right
 
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Old 10-04-2011, 08:27 PM
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aussie 302 Closed chamber 2V heads are best for Ford oems heads especially if you want to raise compression and it will assist with pinging/detonation due to better quench, but over there in the US they aren't as available and are as nearly expensive as proper aftermarket alloy jobbies.
 
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Old 10-04-2011, 09:41 PM
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Originally Posted by 4x4RANGERRICK View Post
Do you have any idea what would be more beneficial towards my delimna as to what heads I should look for to benefit my engine or do I have my stock heads worked on? I can scrape up a pair of 75 heads? Im knew to this as it is my first rebuild and I want to do it right
Check the 75 heads, those may have the EGR hump. The 351C 2V heads are not hard to find and you can usually get those for very little money....heck some guys are giving those away. The best move you can make is to pick your heads and then talk to Tim Meyer about pistons. The 400 has the piston pretty far down in the bore so building compression with just a head swap can still create a problem with detonation.
 
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Old 10-04-2011, 09:46 PM
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Originally Posted by crsmiffy View Post
aussie 302 Closed chamber 2V heads are best for Ford oems heads especially if you want to raise compression and it will assist with pinging/detonation due to better quench, but over there in the US they aren't as available and are as nearly expensive as proper aftermarket alloy jobbies.
Aussie heads are only good if you do something about the piston. The piston is too far down in the bore on a stock 400 to run the Aussie heads. You will still get detonation. It's an easy fix if you are rebuilding an engine. You can either buy a set of Tim Meyers pistons that are made for the Aussie heads, or you can use 351C pistons and an offset bushing in the rods. Been down this road with my 400 but Tim wasn't making pistons back then.
 
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Old 10-05-2011, 12:07 AM
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400 heads

Sorry guys got into a BS headlock with the neighbor who wanted to give his 2 cents why he doesnt grive a ford even though I had towed and pulled his chevy a handful last winter with my ford. Back to the heads and my rebuild 400. What are the advantages of using aluminum heads and bad things other than a great deal of $$$$? I see summit has a set for the 400 6/6L and TMeyer pistons? Or is that a waste of $$$$ and time?
 
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Old 10-05-2011, 09:59 AM
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Originally Posted by 4x4RANGERRICK View Post
Sorry guys got into a BS headlock with the neighbor who wanted to give his 2 cents why he doesnt grive a ford even though I had towed and pulled his chevy a handful last winter with my ford. Back to the heads and my rebuild 400. What are the advantages of using aluminum heads and bad things other than a great deal of $$$$? I see summit has a set for the 400 6/6L and TMeyer pistons? Or is that a waste of $$$$ and time?
Nothing wrong with alloy heads if that is what you need to meet your hp/torque goals. It's often cheaper to buy new alloys instead of rebuilding and porting a set of cast iron heads. However, you still need to do something about the piston. You need to determine what you want from the motor and how you plan to use it 90% of the time. Once you know that, you can sitdown and outline your rebuild and develop a budget. That's the best way to keep from wasting money and ending up with a motor that doesn't perform like you need it to.
 
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Old 10-06-2011, 01:30 AM
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I am thinking 9 to 1 on pistons or 9.5 to 1. I want the overall close to 10 to 1. I did however find more cast #s on the D1AE-A1C heads. Looks like a 26 or 28 stamped in corner both inside corner of valve cover and on the underneath far outside corner of the milled side? and a 2M5 in the middle on spring side. I believe they are 2v? The valves are staggard from each other?
 

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