77 model 470/727

[texas charger 73]

I have a chance to purchase a '77 model 440/727 combo.  Either truck or rv.  I currently have a 73 charger with a 318/904 and 8 1/4 rear.  I know I will have to upgrade rear end eventually.  First off I can get this combo(motor disassembled)  for $400. Is that a fair price.  Next I would like to push about 300-400 hp without dumping a ton of money.  I figure is should be pretty simple.  Have heard them are low compression motors.  What best way to increase compression? Need something reliable, dependable  with a little fun.  Car will see no track timem

[John_Kunkel]

$400 sounds like a good deal. A truck/motorhome 727 might have the short tailhousing that won't work in a passenger car.

About the only practical way to increase the compression is with pistons. Although the '77 440 was advertised at 8.2-1 compression, it's actually closer to 7.7-1 so a decent increase in CR will wake the motor up more so than most other mods. 

[texas charger 73]

I plan on going through and doing a full rebuild.  I want to a try to get around 10.1 compression.  Should the heads be worked or just leave alone.  Plan on a single plane intake and 850 carb. Hp manifolds. 

[Challenger340]

I plan on going through and doing a full rebuild.  I want to a try to get around 10.1 compression.  Should the heads be worked or just leave alone.  Plan on a single plane intake and 850 carb. Hp manifolds. 

With the HP manifolds, "most" single plane intake manifolds can be a mismatch, other than the Holley Street Dominator Intake which seems to be an improvement on just about anything/any combo ? just a very good all around intake !

PISTONS, and Piston SELECTION are absolutely critical, due to the abundance of mis-information regarding actual Compression Ratios published in stock replacement Piston Catalogs particularily for 440's.
DO NOT FALL INTO THAT TRAP ! as so many hundreds have people have that rebuild their 440's with stock "cast" Pistons and end up with a TERD !
because,
there is NO SUCH THING as a "stock" cast replacement Piston that yields anything but mid 8's to one compression in the real world with open chamber heads.
Meaning,
FORGET about using any of the "cast" rebuilder style Flat Top Pistons, they are no where near their advertised Compression Ratios !
You have been warned.

Even for a "stock'ish" type 400-425hp 440 rebuild... about the first Piston to be considered could be the KB237, but "Balancing" because of it's lightweight, and a Torque-Plate for Honing is recommended due to the special ring-end gap requirements for the hypereutectic alloy..... BOTH of which adds cost.

Next up, and my first choice... would be the L2355F Federal Mogul "Forged" Pistons.
Compare their weights to whatever comes out of your engine core... sometimes you are good to go without rebalancing..... T/Plate is recommended.... but these will work without it on an extra .001" wall clearance and NO special ring endgap requirements.
CR with any open chamber cast iron head(86-88 CC's) and a composition head gasket should come in at around 9.5:1, perfect for like a XE268H Compcams hydraulic and the aforementioned 425HP through the hp manifolds, but approaching 500 ft/lbs which is what you REALLY WANT !

Morale of the story.... and most importantly, IMO
DO NOT use any of the stock "cast" rebuilder Pistons.... they are FAR LOWER Compression that what the books say.... and I don't care what your dumass engine builder says.... YOU are now smarter than he is about 440 Mopars.