C9 vs D1 block

While doing (Paul Kane) block mods on Harold's (342g) D1 block today, We made a discovery that neither of us was aware of, or had heard mentioned before when comparing OEM 429/460 blocks. The C9 block was over twice the thickness in the center Lifter Valley as was the D1.This may not be of any Value as this area has never been of any issue /problem to my knowledge.

Yes but aren't the core holes in that area about 4 times the size of the ones in the D1 block?

Yes, They are Dave,and thats another ? Why were they so much bigger and Why do some builders put stand pipes there ?

There must have been a redesign of the casting cores around mid 1969 or so because the 1970 and up blocks don't have the big holes. Back when we did the Block Summit event Jay Cornell who works for IDT gave an excellent talk about what goes into the making of a cylinder block. It was very interesting to hear about how it's done as well as what compromises are made to the design to make it easier to cast and to reduce the scrap rate. For whatever reason Ford must have felt that they could improve some aspect of the process used to cast the big block and they made some changes. Or the tooling just needed some updating, who knows....

The reason stand pipes are used is so that the crankcase can breathe but the oil can't run down through the hole.

Thanks Dave, I'm glad you guy's had the Block summit,because w/o it, I think alot of us would be scratching our heads.

The Block Summit was the first real event for the folks on the Big Ford Forum and it was really a lot of fun for all. Good food too. I believe that everyone learned a thing or two and got to meet and spend time with some nice people.

So....In the end, which would you consider to be the better block? C9 vs. D1

Thom

I don't think that this makes any real difference in most uses. It would be easier to put plugs or stand pipes into the D1VE version. The D1 most likely has a slightly higher (.020) deck height which would give more material if a clean up cut is needed to get the deck in good shape. Both have the thin style webs which isn't any real problem. C9VE will also have the thin pan rail which shouldn't make any difference.