So WHAT IS an R Block, and other questions

[HawkRod]

So I saw an ad selling an R block, and subsequently a question about what an R block was. So I did some searching and came up with the below listed site. While I can't personally vouch for the accuracy of the information, it certainly seems to come from someone who knows a lot. Hope some find this helpful...

Hawk

http://www.shadydellspeedshop.com/faq.htm

Some questions answered:
Can I put W7, W8, or W9 heads on my factory 340/360 block or 59 degree R3 block?
What does a "Siamese bore" block mean, and how do I know if my block is Siamese or not?
How far can I safely bore my block?
How do I identify a specific MP race block?
What are the differences between W7, W8, and W9 heads, and which one is "best"?
Mopar Performance Race Block, Frequent Machining Problems Identified
Using Cometic Head Gaskets

 

[Hemirunner]

Good info Hawk! I built an R3 based 48 degree street engine with the Edelbrock Victor heads. That R3 block weighed as much as a stock 440!

 

[beanhead]

The 'R' blocks (going from memory here) were designed for sustained high-rpm applications (think nascar/circle track racing) so they did different things with geometry and such to keep them alive...not something most people would want/need for a street performance car but interesting history nonetheless

 

[beanhead]

Here's some interesting info too

http://www.moparchat.com/forums/performance-talk/75351-r3-340-block.html