I have found a 400 small block casting # 3951511 4 bolt. Has anyone had experiance with this block good or bad? I am considering a 427 and will dump hard earned money dont want to waste my time.
I would like to know how far I can push this block.
Thanks

 

I have the same casting some say they are weaker than the two bolts because the outer two bolts take away metal making the webbing area weaker it does make sense. Mine is line honed studded balanced hard blocked decked ect I feel as does the shop it is good for 550 to 600 hp it is a 406. To do a 427 I personnally wouldnt use a factory block maybe a 509 casting that has been sonic checked a DART block is cheap when you consider the money you will have in a 427. Unless you are planning a mild performance 427 the 511 block is probably not the best choice, but could make a real nice street 406.

 

Thanks, that confirms what I have found in my research.

 

As someone that has a lot of experience with 400 Chevy engines, I would steer you toward a Dart block. The factory 400 blocks are crap for any type of serious HP. I have been through the mill with them and as a mater of fact, I do not even work with stock block 400's anymore unless it is a very mild or stock application.