Has anyone sonic checked the walls of their 400? I heard Ford fixed the 'thin wall' problem on the 351C when they went over to the 351M/400.

 

I don't know a lot about the 400 block except that the truck block is better to have because it has reinforced web mains whereas the car block does not. I hope that may help.

 

I didn't know there was a differrence between the truck block and car block. Is this production year related like with 1972-1978 Dodge 400 and 440 motors vs pre 1972 (thinner webbing)? The reason I was asking is because one of the shops I've dealt with in the past bores them to 4.100". This sounds a little excessive to me with the history of the Cleveland style engines. I'll sonic check anyway but I was just wondering if anyone else done this already.

 

I'd not recommend that. Even .060" over is too much. I think the problem is more of a core shift issue rather than it just being thin to begin with.