Originally posted by Steve karch
I may be wrong here but this is what I think. GM didn't develop the 400sb as a performance engine because when this engine was introduced the performance era was over. This motor was developed to be used in trucks as a torque motor. The extra displacement was used to compensate for the effects that the emissions systems of that era had on power. GM would be remiss in developing this engine as performance motor as there was no market for a performance motor at that time and it would be money wasted. This scenario seem logical to me. It took a while before the performance aftermarket took notice of this engine and began to understand it. That is why performance development has bee lagging. Correct me if I'm wrong please but that is the way I see it happening.
YOU HIT IT RIGHT ON THE HEAD! chevy put these engines in trucks & LARGE cars for two reasons. emissions, & they had the torque to pull the extra accessories & the weight of the heavy cars/trucks. they didn't plan on hopping them up, thats why they never had steel cranks from the factory or even a 4 barrel carb, but the block design was done to make it as strong as possible to take the extra torque the 400's made (i have seen one with a 4 barrel & 186 heads from the factory) . i'm hear to tell you, if i hadn't found a 400 block i would have built a 383. 383's are great performance engines & shouldn't be over looked at all. for the average street car a 383 is all they will ever need. there's to many 600 hp 383's running on pump gas to over look them.