My opinion,
Quality control at Dart is much better.
The Dart casting just appears to be more dense or higher quality, than the Merlins. I have the most expensive Merlin Cast Iron Race Block in my shop now sitting alongside a Dart Big M with Billet Caps and it is easy to see the quality difference in the castings.
I also like the Dart lubrication system and the placing of the external oiling connections better too.
The deck ht from Dart is right on when comparing side to side.
I like the way the Dart center bolt provisions are much better than the way Merlin does them.
And last but by far not least, It will be a freezing day in Hell before World Products ever gets anymore money from me.
I paid in cash by Money Order upfront for a new Merlin II and was promised they would ship in no longer than 3 weeks. After tons of angry phone calls becuase of all the lies in Michigan and also all the lies of Mitchel jr. and after I lost my customer that block finally was delievered over 10 months later. They also charged me $250.00 for freight. I get Dart Big M blocks for less than 120.00 freight now.
The Merlin will cost a little less.
Depending on where you are I have a good source for both Merlin and Dart, but refuse to buy Merlin.
Bill Hendren here, one of the contributing members I believe can also help you in Dart Products and also I think Merlin. Give him a phone call. His number is usually included in his postings.
Hendrens Racing Engines
1310 U.S. Hwy 221 North
Rutherfordton N.C. 28139
828-286-0780 Bill, Steve, Mike
www.hendrensracingengines.com
Ed