choice for new motor- 82 K10

[Grim 82]

I think my mind is made up, but I'm open to thoughts and opinions, and anything I might be overlooking with the swap. 
This motor will replace a 350 in a daily driven 82 4x4 long bed with a 700r4, np208, 33" tires, EPS intake, MSD ignition, and Holley carb. Headers will be getting replaced with ceramic coated Hooker long tubes at the time of the swap.

The internals of these motor choices are guarded like the Colonel's secret recipe, so no cam specs, valve size, etc. The guy building it is somewhat of a local legend, and I know he builds the best motors around if you can afford them. I have the oppurtunity to get one of his motors, I just need to pick which one I want. Any one would be broken in and dyno'd at his shop before it leaves, and the only thing I need to swap over is my intake and distributor.
As explained to me:
The 355 will make about 350 hp, a somewhat mild replacement but it will have a pretty lumpy idle which may not be the best for the street.
The 383 will make around 390 hp and be a torque beast but then why not get the 400.
The 400 will make about 425 hp/450tq and he'll throw in the flex plate and dampener.
I like the idea of the 383, but for the same price...Any reason to stay away from a 400? I hear good and bad about it. I know it will be built right, but wondering about any potential problems with the 400 design compared with a 350 based motor. Thanks

[TexasRed]

If the 400 is built with 5.7 rods and the heads drilled from the steam holes, get it.

[bake74]

     If he is as good as you say he is, the problems with the 400 will all be eliminated.  Go for the 400.

[1980c10]

The hp/tq numbers are pretty typical for a mildly built small block. I had a non legendary but reputable shop build my 355 for a good price and warranty. good idle and dynoed at 393 hp @5200 and 432 tq.
Specs for this build come from the advice of members from this board.

[thirsty]

Hard to beat cubic inches!

[martin79]

Daily driver go 350,........or get a small  car for daily and put 400 in truck !

[VileZambonie]

The 400

[Lt.Del]

I got a 383, as everyone here knows and am very happy with it.  I got it because it is a 350 on the outside and has boat loads of torque, and everything bolted right up (alt, power steering pump, starter, a/c brackets,---everything).  I am guessing the same may be true for the 400, since it too is a sbc.  So, all else being equal, if your decision is b/w a 383 and a 400, since your crank will be a 400 if you chose a 383, might as well make the rest of the engine a 400.   

The only drawback, possibly, with a 400, and i am no expert on a 400, is they are not a common as they 350 blocks.  But, if it is built correctly, all you need is one anyway. 

[thachevythang]

Take the 400! Set yourself apart from the other small blocks! It's always fun to say "So what, mines bigger than yours!" LOL

[Grim 82]

Thanks everybody for the input. I'll be getting the 400 on monday. I had him put in thicker head gaskets so I won't have to burn premium gas, and he's painting it orange.

So, he's including the dampener and the flexplate. It comes with the oil pan and timing cover. Correct me if I'm wrong but the Edelbrock performer intake and MSD distributor from my 350 should fit the 400. I can reuse my valve covers since they are 882 heads that use either center bolt or perimeter bolt covers. All the accessories should bolt up, including the clamshells? Am I missing anything? Does the 400 use the same plugs as a 350? I have been using Delco R43TS plugs.
Thanks

[TexasRed]

Use the same plugs that came with 882 heads, that's where they screw into.

Everything else should bolt right up, I'd imagine. Same distributor, same intake.

[Grim 82]

Use the same plugs that came with 882 heads, that's where they screw into.

I'm not sure what you mean.
I'm wondering if the 400 with 882 heads require the same spark plugs as my 350 with stock heads (CR43TS), or if the new motor requires a different heat range or length of plug. I'm not sure if the spark plugs will come with it or not, so I could re-use mine from the 350 or else buy new ones if they are different. Thanks

[TexasRed]

Sorry, I thought the heads going on the 400 were the same coming off the 350. The spark plugs *should* be the same but you may want to ask your engine builder.

edited to change: "They" to "The spark plugs". People may have been confused with the pronoun and thought I meant the heads should be the same.

[beastie_3]

The heads need to be converted to fit the 400. Something about steam holes.

[Grim 82]

Yep, that's all being taken care of by the builder. I asked about the heat issue with 400's and he said this one will likely never run hotter than 195. When I get it I'll just have to bolt my intake, carb, and dist. on, along with the sending units, spark plugs, exhaust, and anything else I might be overlooking. I'm not familiar with the subtle differences between a 400 and a 350, so I don't want to mess anything up, like using the wrong plugs. I'm guessing it will come with the correct timing tab on the cover. If not, is it the same as a 350?

I just don't want to get started on the swap and then have to push the truck outside for a week while I wait for my Summit order to show up so I can finish it. If anybody can think of anything else, I'm listening.
Thanks