Wanna swap out my 305 with another shortblock, and build the rest of the engine myself as I go along. Now I need to locate a good 400 shortblock, this is the only I have found so far. Seems as a nice deal since a bowtie block or Dart little M block is $2000 alone.

The 406:
http://www.coasthigh.com/Assemblies/...bmit2222=406ci


The 421:
http://www.coasthigh.com/Assemblies/...Submit22=421ci

Guess it's best not to go for the 434 to be able to bore it once over at a later stage.

So is this any good? And are those pistons any good at all?
My plan is a mild motor (mild heads and cam) lots of torq, and be able to take a big shot of nitrous (250- 400?) So I'm considering the all forged one of the 406, and the 421 only come in all forged if I understand it right.

 

What exactly is "an appropriate engine block"?

My defination would be a Bowtie, Dart, or Motown block.

FWIW, the bore/stroke for their 406 Street Fighter would result in a 377-388, not 406.

 

Seems like you're right aboutthe bore stroke vs displacement, at least for the 406. As for the 421 the borexstroke seems to be right.

I emailed them about the block's, i too wondered about if it was a bowtie, dart or other. My thought was stock block for the 406, and bowtie or dart for the 421 and 434. Perhaps that this is not the case, but I thought it was mandatory with these block's when going this large, but maybe not afterall.

At least the price difference from 406 to 421 could imply a better block..

So you think they really sell a 350 or 383 as a 406?

 

Webmaster error, I'm sure.

 

Got a reply from them about the block's they use:


"2 or 4 bolt chevy blocks.. we can also get aftermarket blocks.
Let me know what you would like, thanks!
Marty
310-832-5939"