What should I do with this 400 ?

['Cuda Hunter]

I have answered a few of my questions by re reading all this. 
I'm a little slow following you Chryco.  But I'll catch up. 

[Chryco Psycho]

Yes that is the kit
WHy 451 , this is more personal choice but more CI is not nessisarily better , the more ci the higher the pin is in the piston , & the shorter the piston becomes , this make it harder to keep the piston straight in the bore allowing it to rock , it can add extra stress to the piston skirts & push the pin under the oil ring ,  you also lose rod ratio so the rod is more sideways in relation to the cylinder adding side loading to the piston ,  to me this shortens the life of the engine & creates more of a short life race build than a long term street engine . A 451 build takes 7 lbs off the rotating mass of a 440 & gives up very little , allowing the engine to rev a lot faster without sacrificing strength or durability .
The 451 will provide more than adequate power for a strong street build , ask some of the people who run a well built 451 

['Cuda Hunter]

Ok. That's kind of what I thought you would say. 

I'm in.  Sounds like some fun. 

Since my heads are 83 cc, That would give me approximately 9.87 compression.
Would I want to ask 440 source if there is a different sized head gasket to make a little more compression?

[Chryco Psycho]

I would ask what gasket thickness they use to calculate their comp ratios

[HP_Cuda]

It's on their website. My setup got me around 10.5 with .36 thickness cometic gaskets.

[1 Wild R/T]

I would ask what gasket thickness they use to calculate their comp ratios

They state .039 at the top of the page.. The thing I'm not thrilled with on their 451 kit is the pistons are spec-ed at .017 in the hole, add .039 for a head gskt & your at .056 the very edge of useful quench... At the very least I'd deck the block an extra .010-.015 which some say could cause intake alignment issues but since the .039 head gskt is .018 thicker than a stock steel shim gskt it's a non-issue...

Course if your using stock open chamber heads theres no chance of quench anyway..... But I'd still deck the block allowing for future upgrades..

Another thing if your considering heads is there's a new option recently thats getting very point reviews from the machine shop/head guru types... These heads are cheaper, they claim the quality & flow are excellent.. Not a serious race head but a excellent street/mild race piece... For more info search Sidewinder Cylinder Heads over on Moparts...