We machine a lot of Dart blocks and we do what we think need to be machined
every thing has to be checked
Here is a list to what we do to a Little-M block when we machine one
CNCBLOCKS
We machine alot of Dart blocks for engines builders and other shops.
95% of the time most guys want main studs installed and after installing the studs in some cases we see the housing bores tighten up, So we line hone the main line on the 400 blocks to 2.8415
The blocks come with a 9.025 decks and most piston, rods and cranks require a 9.000 deck for zero deck.
Lifter bores we make sure they are to the GM tolerance of .8438 to .8443 but again most of the time most guys are asking for .904 lifter bores now.
The cylinder do come on your block appox. 4.120 and do need to be plate honed using the same gasket and hardware you will be using in your build.
Freeze plug and rear cam plug holes need to be chamfered.
Bottom of the cylinders should be camfered.
All the pipe plug hole should be taped deeper
Rear main bearing area needs to be deburred.
Water holes in the decks need to be matched to the head gasket.
On the 400 main line blocks fit up your oil pump and oil pump shaft and distributor to make sure that you don't need to any extra clearancing.
Thats pretty much what we do to the Little-M blocks.
And we charge for the block and the machine work 2695.00
When building a performace engine everything has to be checked and clearanced to the builders specs.
Dart blocks are great foundation to start with but everything needs to be checked before assembled. I MEAN EVERYTHING