Buildup starting with a 400?

[NJDevil]

My 73 Challenger currently has a 400 in it.  I want to stroke it if it sonic tests ok.  I'm just in the beginning stages here and wanted to get some opinions from those that have done it before. I just got a driveshaft from Dennys that will be here in a couple days and will be pulling the 727 out and rebuilding it.  Might as well put a bolt in sprag while I have it out right?

A Couple questions

1.  Start with the 400 or go to a 440?

2.  I'd like to make between 500-600hp?  Can I get there with a converter, stroker kid and good heads(Indy?) if not whats the Best bang for buck way to do it?  I've got about $4500 to play with.    Just a street car with maybe once or twice at the track per year. 

3.  Opinions on how big to go? 400> 451, 470, 500 or 512?  Advantages? 

I know these are questions that have been answered 400 times before but this is my first older car that I'm building.  Use kid gloves. 



Thanks for the help!   This board is awesome! 

[1 Wild R/T]

Use the 400 block, it's stronger & more compact... Any one of the strokers listed can do 500+ horsepower.. I'd probably do the 470 or the 512.. I'd drop the 500 because it requires oil ring supports which aren't the best for street use..   

The 451 also has a great reputation for making serious power & is worth considering for sure but I'm a fan of big torque & you get more of that from bigger cubic inches...

Which brings us to the 512...  Lots of them running so obviously it works but the reason I would tend to shy away is the rod angle & piston height....  The piston height is the same as a 451 at 1.32 but the 451's rod ratio is 1.802  the 512 rod ratio is 1.537, the lower the number the greater the side loading on the piston.... With a taller skirt the loading is less of a concern but the 512 has both a short skirt & a high rod angle... For a street motor I'd probably let this one go....

Which brings us to the 470.... The one that seems to never get built, yet the one that for a street motor seems to have everything going for it....   1.669 rod ratio, 1,48 piston height, enough displacement to destroy things...  Only reason not to build it is the allure of bigger is better but IMO this is the one to build for a street combo..

[Chryco Psycho]

I tend to stay on the smaller side with the 400 block to maintain rod ratio  so 451 or 470 is what I would look at .
 I would use a raised port head so you can use a 440 intake such as the Holley street dominator . Indy will work I would look at the new Trickflow or Super Stealth heads .
 440 source has  good 400 stroker packages

[73restomod]

Me I like the 470, I think for a standard size port size, it's just the right amount of everything.

[moper]

you can pretty much count on anything with an oil ring support having a shorter life span. But without - that goes up to 505/512" - those are fine. The rod ratio in the longer strokes change to what many other major manufacturers has warranteed for years. I've built up to 4.25" stroke in B and RB. With the Chevy crank pin size and the longer rod they are brutal in terms of torque, and they have surpassed 12K miles at 560hp/580tq. these are with ported, std port openiong heads (Stealths & RPMs). In terms of packaging - the B wedges have fewer manifold choices but that's hardly a big problem.
I'd say pick what you want, and build a matched package, and you will be smiling.