How does a 2 bolt main Dart block hold up against a 4 bolt 350? Is it stronger, just as strong or weaker? Its for a 383

 

The Dart block would be superior to any factory block, even if the Dart is 2-bolt main.

Any particular reason you're going with the 2-bolt main, other than slightly lower price?

 

Ya its in a crate motor. How much 'tougher' would a splayed block be?

 

as an example... 2bolt is strong... a 4 bolt is 10 times (just an example)... and a splayed 4 bolt is 30 times stronger (again just an example)...

 

2-bolt blocks are stronger in the main bearing web. 4-bolts prevent cap "walk" but weaken the web. Splayed 4-bolt mains lock the caps in place without weakening the web.

2-bolt blocks were used exclusively through 1967. If you think no power was made with small blocks until after 1968, you need a history lesson.

Bottom line: 2-bolt blocks are very capable. 2-bolt Dart blocks are even more capable. Splayed 4-bolt Dart blocks are awesome.

 

For the average person, a 2 bolt block is more than strong enough. It's when you start to use huge amounts of a power adder that the extra bolts in the mains are really required.