Question about 440 heads

[73ChargerSE]

440 heads can be bolted on a 400, correct?  I may be able to get a nice set for a decent price.  Would it be a significant horsepower gain?  If not, what is a cheap way to increase head flow?

[Bandit72]

  sure will fit, depends on the casting numbers whether or not there is any real gain...some 400's had pretty good heads to start with

[daves68]

440 heads, 400 heads, 383 heads, it's all the same thing- meaning they easily interchange. Go by the casting numbers to determine which ones you are considering. Remember that the #452 heads that came off of the 400 we're actually pretty good, flowed good and have the factory hardened valve seats that you will need for todays great fuels. Older heads, 906,516,346 will need the valve inserts installed by a machine shop. Presently working on 2 sets of 452's myself.

[73ChargerSE]

Where are the casting numbers on the heads? I have 2 sets of 400 heads (both on engines), so I'll check both.  And the 440 heads have the same casting numbers, because they're pretty much all the same?  Also, what makes a 400 Magnum a Magnum?

[daves68]

The casting number is located in 2 places. Take off the valve cover and look around for a cast in raised 7 digit number. The last 3 digits, in your case, will be 452. Example 4006452. Same with other heads from other years. The second location is on the underside of the head. Pull them off of the engine and flip it over with the combustion chambers facing up. Under one set of intake runners will be the same casting number as above. The differences in heads is the model year, not the engine size. Different years had different features-valve size, flow, hardened seats, etc.They will all swap from one size B engine to another. A 400 cube 452 head is exactly the same thing as a 440 cube 452 head.  Magnum had little better cam, exhaust, and carb. Same basic engine, a few added goodies. That's what makes Mopars so great. Relatively easy to upgrade.