What's the appeal of an aluminum engine block?

[Barry_R]

Its been a long time since I posted here - "life" has kept me a bit busy...

I can back up a few statements. Nobody has any aluminum blocks. I have not seen one shipped for months. I get promises - and unfortunately have repeated them to customers - and then I get no parts. If there were an alternate I would go to another supplier. But out of the FE block suppliers - Side Oiler Garage (former Genesis), Pond, Shelby, Dove, BBM - none of them have a block to ship. I have already paid one of those guys for five blocks in advance and received nothing in return.

We have a vacuum impregnation facility here in the Detroit area - out by the airport. Very nice guy who is justifiably proud of his services. Every single aluminum block I do will get impregnated from now on (Bill - your's was done too) after I had an issue a few years ago. The cost is added into the build, but I do not call it out because customer get nervous about a process the might not understand. This place does a bunch of military and OEM transmission stuff.

The weight savings is nice and I can fully understand the desire. The blocks themselves seem to be consistently inconsistent in quality. I have always been able to build them into good engines but they are always a challenge and I kind of agree with the sentiment - they should cost 20% more for labor because of the extra effort required. Every single fastener needs to be retightened after they run - the aluminum growth seems to loosen them all up. They leak - probably for the same reason. I suspect that the OEMs use better alloy and a much more sophisticated process for fasteners, seals and gaskets to avoid these problems.

The 427 stuff is definitely cool - given the choice I would prefer to build an iron block every time. We pretty much never have any issues with 390 based 445 builds, and we do them at a rate of two or three per month.