What is the R5 for on this block?

[crossram 426]

wondering what the R5 stands for?

 

[BeepBeepRR]

NASCAR R5 race cast-iron block P5007427 than it is a HP replacement block, the race sanctioning body has very specific rules relating to blocks and what is allowed that can make these projects extremely difficult. Grabbed that from this page.

Also this... The siamesed-bore cast iron 440-style block is P5153860 which has a finished-bore of 4.50".

 

[knk-mopar-parts]

Is it just a stamping or is it cast on there?

 

[knk-mopar-parts]

R5 are small block race blocks. His is a big block

 

[BeepBeepRR]

Just posted a part number for the 440 in my last edit. So apparently they make the R5 in a 440 too. P5153860 Not sure if they were talking about 5.7's but they mentioned you needed P7 heads for the R5. But that just may be a modern Hemi.

 

[crossram 426]

Is it just a stamping or is it cast on there?

cast, sits out from the block

 

[crossram 426]

just wondering what it is, just a stocker or something more? they seem to have highlighted it for some reason...

 

[mmissile]

P7/R5...smallblock.

 

[crossram 426]

no it's an RB 440.
just found out casting number 4006630-440-7
75-78 block?

 

[Budnicks]

I think the R5, in this case
{it's obviously not the "newer" R5 racing NASCAR style SB}
is just a replacement warranty style, dealer sold service block
when it's form as a 440 RB replacement {?}
I can't remember/not sure if they had them for 383-400's
with that "R5" casted designation...

Don't quote me, I'm going off poor memory...

someone may clarify it up...

I saw this in a Google search,
"1978 Mopar 440 block with a R5 casted into the front left side"
http://www.justanswer.com/clasic-cars/3i64i-trying-find-440-big-block-motor-need.html