Non Siamese 351 Ford block using an old Y2K turbonetics. It did have modular iron caps. We also did a procharched sbf on a better Motorsports block that made 1635hp on the dyno.
I’ve never built a sbm to failure but I was planning a 700 hp build two years ago. I saw enough evidence on here to convince me that my block wouldn’t live long at that power level. I then talked to two reputable builders and both said the limit for a sbm is right around 600/650.
