BBC: Merlin or Dart Block?

Guest · Post by **Guest** » Sat Jul 17, 2004 3:02 pm

Which is better?

CNC BLOCKS · Post by **CNC BLOCKS** » Sat Jul 17, 2004 11:48 pm

We have machined both Dart and World blocks, We have the ability to probe the blocks in our CNC machine for deck heights, cylinder location and size and lifter bore placement and both seem to be very good in that area.

speedtalk · Post by **speedtalk** » Mon Jul 26, 2004 5:49 pm

I'd like to know this one myself. Anyone else have some experience?

Guest · Post by **Guest** » Mon Jul 26, 2004 9:20 pm

Well i can tell you the ford dart blocks are not machined well .The decks look like the machine stops half way thur the pass and jumps down .The 3 that i looked at and measuered the lifter bores had .003-.0035 clearance in them and the mains were all over the place.

mike

Matey79 · Post by **Matey79** » Wed Jul 28, 2004 8:19 pm

Both blocks are nice pieces, certainly rigid for major horsepower.
-The World Merlin has lifter bores .0008 oversize, but seems to cause no problems, and the main housing bores are set on the high spec. Also a major concern is the casting sand/iron in the water jackets. Cylinders certainly will run hotter if not removed. A bent up screw driver or saw blade usually will break it up.
-The Dart Blocks are all good in quality control, but the lifter bores are .0005 tight, requiring honing and the main housing bores are on the low, usually requiring align honing. Perfect for custom engine builders, allowing the builder to determine clearances.

speedtalk · Post by **speedtalk** » Wed Jul 28, 2004 11:59 pm

Hey Matey79, Thanks for joining the forum. Nice post!

Racer7088 · Post by **Racer7088** » Thu Jul 29, 2004 7:19 am

Yes,

The Worlds I have done were on the Chevy high side on the mains too.