Is there a noticable benifit for running the larger bore and unshrouding the valve more on a 383 buildup?

 

If you are going for the 380 cube range, a .030 over 400 bore with a 3.48 stroke from a 350 gives 377 inches.

IMO, yes, the larger bore unshrouds the valve and helps the flow. Some head manufacturers give head flow numbers for a couple of bore sizes. Larger bores have bigger numbers. Also, with the shorter stroke you can spin it faster for the same piston speed.

As far as the torque curve, an optimized 377 should get about the same shape torque curve as an optimized 383, and about the same output.

There was another thread recently where this came up.

Unfortunately, to do a good 377 with 350-size mains, 4-bolts, etc, you pretty much start with an aftermarker or Bowtie block.

Winston Cup 358s push the bores to something around 4.18 (NASCAR has a limit of course), so that gives a stroke around 3.26.

My $.02

 

I was wondering bcuz I was going to build either a 600hp 383 or 400 and was wondering if the larger bore was worth it on a 400.

 

Of course, you won't be able to use your LT1 heads on a 400 block.

Rich Krause

 

It was going to be a 400 sbc or a 383 LT1.