**600hp sbm block limit? Or is it bs!!**

Thanks man. They are a labor of love and a full time job all wrapped into one. I will tell you anything you want to know, so if have any questions fire away. The Dart is a twin turbo 344" stock stroke 4.070 bore 1970 block. It has a Eagle 4340 crank in it GRP aluminum rods, and Ross heavy as all get out very old turbo piston (custom made for me in 1997). I originally went turbo with it in the late 90's. The engine in that car was built in 2018 and has seen a lot of street miles and a lot of abusive passes. The key to this one and the other one is detonation. Detonation kills motors. Some tolerate it better than others. I am super super careful with the tune up and very conservative on timing (20 degrees total). Both the Duster and the Dart are 1970 blocks with excellent machine work, carefully blueprinted and assembled. No hard block, no girdle just the stock block. They do have 4 bolt splayed main caps but I truly think that is a detriment more than an advantage because the block has no meat for those 3/8 bolts on the outside main bolts. Plus they go in the cooling passage and for me I would rather run a stock cap. Which I did in the 90's. The Dart has made 1222 at the tire at 20 psi on the Dyno at the wheel. It made several passes there with no distress. The Duster made 645 on the Dyno (flywheel) and we hit it with 275 the second it leaves the line. The tune up is kinda rich so I would bet its more like 225 to be honest but still that is 870hp. it made 585 torque on the motor (its 14:1) so it is probably a solid 900 torque on the hit. The Duster motor has over 200 passes on it and is 17 years old.
What kind of timing are you running base on motor and n20 for the duster. I would have to think it’s harder on parts with high compression and n20 then the turbo