Big block Chevy build

What block would you choose and why? The goal is 1700 to 2000 hp. I have previously had an iron bowtie block and made 1684hp on the first pull. I don’t have money for a billet block. If I did, we’d be discussing hemis. So I have velasko billet crank 4.25 stroke with bbc mains and hemi rod journals, 6.680 Fowler light weight rods with 1.090 pin diameter. Big Duke heads are on the way. Going to use a 10.2 deck. Suggestions will be mulled over…

 

I’ve ran both the cast iron Merlin 4 and cast dart big M in that power range with no issues. At the top end of that you may start to get some main cap walk and metal transfer, I noticed it worse with an aluminum block, the Merlin was best when it came to the cap walk. Obviously a billet block with cross bolted mains would be best either Chevy based or hemi based...and at that price range I would go hemi as well.

 

I have used a Bowtie 10.2 with 14-71 HH at 45%over, worked Brodix BB2X in pulling applications, both filled and unfilled with no issues.

 

PBM uses higher grade cast iron in there Merlin IV blocks and I think Dart has jumped on board to compete as well. Either block will handle that power level with no issues as long as your tune is up to scratch. The Merlin comes with ARP hardware and a clean sheet design. Comes with billet steel caps, 55mm cam tunnel, 904 lifter bores as standard, and are heavier than the Dart.

 

I ran dart and Merlin 3. 4.500 up to 4.61 bore. 3.8 up to 4.375 stroke.

Went 226 mph at 2050 lbs. guessing that’s north of 1800 hp.


All of them chattered cast caps pretty bad, but never cracked them or anything. Went to billet caps and shorter cranks but they still moved around a little. If you chased it by remachining every time it would be a pain, but I just bolted it back together.

 

Ive had people suggest an aluminum block but I think cap walk would be an issue. I am in between the Merlin 4 and the Dart. Its just alot of weight though.

 

I am at the 2500 hp range with a Brodix aluminum block Hipped and 1/2 filled with steel caps. The cap walk is real bad, I get pissed off every time I take the caps off and see the metal transfer. Like others have said there is nothing you can do but just put them back on. Main bearings look great each time I take it apart. I increased the stud torque 10lbs on the inner and outer but dont think it has helped.

 

try anti - seize under the caps

 

Anti seize under the caps was suggested to me, but it was after metal transfer had already occurred so at that point I don't see it helping.

The other suggestion is billet aluminum main caps, since the 2 metals are the same there should not be any transfer of metal.

Either way the caps are still walking.

I am real close to putting a deposit down on a CN Billet block with cross bolted mains. I think the wait will be worth it in the long run

 

What about a New Century block? It's still cast but cross bolted.
A lot of BBC guys around here are running them with great success.

 

I have been told New Century is way behind or not taking new orders, is this true? I have been contacted by a couple guys wanting to buy them but could not get them to return calls.

 

I would recommend Cross bolt main block , I cracked the main webbing in Brodix solid block after 68 passes and split Donovan solid block after 13 passes , that was @ 44 pounds of boost , if you making low boost 25 to 30 psi , you will probably get by not using cross bolt block , I just purchased new CN cross bolt block .