[hardline_42]

Originally Posted by johnjzjz

The Pluses we raced them great power --- the negatives -- they run hot - the load on the cylinder walls is greater than any other SBC ( reason ) all except the 400 uses a 5.7 length rod the 400 has a 5.56 length rod, every one we had cracked the # 6 cylinder wall -- they don't rpm in stock form -- and the 2 bolt blocks turned out to be stronger for us than the 4 bolt -- jz

I'm a little biased but I have to chime in with a few corrections. 400's DO NOT RUN HOT! The issue with overheating is not due to the siamesed bores (every bowtie block would be having the same problem if that were the case) but mainly because of the fact that people swap 350 heads on to them without drilling the steam holes. I have drilled them myself on all of my 400s and never had a single overheating problem running a stock radiator and water pump. Stock 400s do have short rods and will not hold up at higher (above 6k) RPMs. A common upgrade is to go with 5.7" or 6" rods which may cause clearance issues (not always). Two bolt blocks are known to be stronger than four in the case of the 400s. The casting numbers in order of strength are 817, 511, and 509, the 2-bolt version of each being stronger than the 4. ANY STOCK BLOCK IS GOOD UP TO 400HP. Anything more and you will want the better castings.