383 is there any big difference!

[have issues]

  I was just wondering  have 66 383 2 barrell engine short block only stamping is R on pad next to dist. Just picked up a set of 516 heads. How far off from a four barrell HP am I?

[moparteacher]

From a 66' 383 HP? Probably cam, intake, carb, double roller timing chain. and valve springs.

[jess13]

The bottom end was all the same until they went to cast cranks in early 1970's (well except for some very early 383 cranks was a little diff).  Two barrel , 4 barrel,  it didnt matter.  Just camshaft & small things is what made the diff.     The 516 heads may have a smaller exhaust valve,  some did, and some didnt.  If it has the smaller exhaust valve you can just get the bigger vavle put in.  That will make a good little combo you have there.


Jess

[ksdartguy]

Yes, not much difference.
The piston height is down some on 2 bbl engines.
If you are rebuilding put in some KB 162s and run the
steel shim gaskets.
Depending on the decks, you should be close to 10.0 to 1

[PureGTS]

Not a whole bunch.
  You're probably going to want to rebuild it anyway just to make sure of what you have inside. So increase the compression a little bit and add a bit more cam and you're there. I'm not a big fan of steel shim head gaskets, unless they are the MLS (Cometic) types, so I'd add some compression to compensate for the Fel-pro 1009 (.040") compsoite gasket.
  The 2bbl cars' cams were around .410 -.420 lift. Nothing really histerical, but compared to a .450-.455 magnum cam, the were lacking the HP for obvious reasons. A better cam would be a good call too. It doesn't sound like you are looking to go crazy with this engine so keeping it simple in the cam dept would be a good thing too. Based on that, I'd go with anything .484 lift 284 dur or less. Anything more would start getting into critical checks areas.