Scooby Senior
It's a block which is closed rather than open 
Tougher/less likely to distort (heavier), can be run with higher boost.
Tougher/less likely to distort (heavier), can be run with higher boost.
Scooby Regular
I'm sure there's a really good technical explanation but in "plain" English:
Closed block - more metal between the cylinder heads means the block is stronger as isn't "open".
Open block - has less metal betweent he cylinder heads.
You'd want one if you're going to push up the power to funny levels and perhaps for a bit of insurance.
Closed block - more metal between the cylinder heads means the block is stronger as isn't "open".
Open block - has less metal betweent he cylinder heads.
You'd want one if you're going to push up the power to funny levels and perhaps for a bit of insurance.