Upcoming FE build: plan coming together

[olddog]

Originally Posted by Barry_R

Don't want to upset anyone. But Ford did not turn 390s into 428s for service. You occasionally find a 391 truck block that'll go to the 428 bore, but they are not the norm by a long shot. Some service blocks were apparently 391/428 castings that could be machined as needed - but they had 391 features like the big distributor hole and the compressor oil return passage. Most .080 over 390s are ebay specials that'll split a cylinder wall somewhere down the road. Could last hours, weeks, or years - no guarantee.

I'm not upset and respect your knowledge. My source for my statement was "Ford Performance" by Pat Ganahl page 50.

"All replacement 428 blocks sold by Ford after '72 were bored-out 391 truck blocks." He then goes on to describe the differences in the truck block. The previous sentence stated that some 390 blocks can be bored to 4.13 (428) if sonic checked.

My memory is not what it once was. I remembered it as the 390, but he stated 391. I know they are not the same, but I kind of lump them into the same catagory.

I think you were saying some of the same things. Do you agree with the quote from the book?

Jim Dove's web site also states some 390 blocks can be bore to a 428, and he has a chart on the allen wrench test between the cylinders through the freeze plugs, as a quick way to rule a block as worthy of sonic testing.

A couple years ago the Ohio Cobra Club's raffle car for the London show had a 390 block bored to 428. At least that is what I remember. I believe this is practiced and have read several sources saying it is ok if there is enough wall thinkness. All sources caution that most 390 blocks do not have enough meat, but some do. Just because something is done by many, it doesn't mean it is the right thing to do. So I am not argueing it is right. I just want to be clear when I ask "Is it your opinion that even if there is enough meat, there is a higher risk of failure?"