I have a 350 4 bolt, needs rebuilt. I can get a 400 virgin 2 bolt, cheap. I'm having trouble deciding whether to build a 355, 383, 377, 406, or 421.

First off, it has to be streetable, but I want a decent amount of horsepower and tq. I like to hit 6,500 rpms. And I have to do this on a budget. Whatever I decide I will throw my Wold S/R heads on it, and will go carb because I don't like TPI anymore. I also have a 2,300 stall to go with it too. Any suggestions will be greatly appreciated. Thanks in advance.

Justin

The no-brainer to me is rebuild the 400 to a 406 using 5.7" rods. That will be slightly more expensive than building the 350, but the extra 50 cubes and torque will make it worth it. One disadvantage is the need to use externally balanced flex plate, which is typically 14" and requires ministarter.

6500 RPMs is possible but unnecessary. You'll get as much or more power out of a 406 at 5800 RPMs as you would a 355 at 6500. It will also be more streetable.

What S/R's do you have? Whatever they are, you'll need to drill the steam holes per World's instructions for use on a 400. If small chamber, watch your compression ratio (may need to consider dished pistons to avoid premium-only, if that's a concern to you).

A 383 is also a nice option, but would be more expensive than either a 355 or 406 and would need the same externally balanced parts.

The 377 is probably the least streetable option, and certainly amoung the most expensive. 421 - that would require a crank that you don't already have.

Whatever you end up doing, send your unused parts my way...