I'm a Dart user , but I'm looking to use a Merlin 4 for a new build , the merlin has the option of 55mm Cam and 904 lifters . The Dart I have to have it machined .

Dart will do all of that stuff for you too. Even the x pattern for big chief heads.
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Haven't looked at a Merlin block in a while but I really prefer the dart. No matter what setup it comes with, it needs a good amount of finish work.

The last Merlins I dealt with were rough as a cob , thats why I always prefered the Darts. Just wish someone would offer an option
for a raised cam and 55mm or 60mm cam tunnel and .904 lifters or larger , Without a huge up charge or 2nd party machining.

I know this thread is a bit older but does anyone have input in 2025 / 2026? Im looking to buy a pair of blocks and it's down to these two again. Most of my experience is merlin IIIs and IVs

Eddie Young only uses Merlin if that tell ya anything.
Their latest offerings are very well made and machined.
I have .904 lifters and 55 mm cam

It seems like all the popular builders use Merlin so I'll continue to go that way, thanks for confirmation

So heres MY experience:: the merlin 1, 2 blocks were plagued with issues (the lifter bore on my 2002 era merlin had "chamfers" at top, it had virtually NO oil pressure at 1000 rpms or less, I had to fix it by having base circle of cam reduced. The inside lifter valley area had no extra holdown bosses and was so thin they couldnt be added. was NOT a great experience. Fast forward, I bought merlin 4 a few years ago and they were as NICE or NICER then recent dart blocks I had bought. Y=They came with studded mains from factory too, darts do NOT, I actually prefer them over dart these days, Smitty

Summit, same as BPE, cast in Germany.

Just bought a Merlin IV. I'm not machinist but it looks great in the box and it came with a free hat and sticker!

Eddie young and Teague use them so that was a good enough testimonial for me.

As of a month ago, Dart was backordered on everything until June/July and that was just an estimate. I called them and that's what I was told. They lost their foundry here in the states. I read it had filed for bankruptcy, that they are in the midst of changing foundries and will be cast in Germany now. Oddly enough, the new Summit Racing and new Blueprint Engines blocks are also cast in Germany. Easy to connect those dots maybe?