Here's what Andy posted on one of the other modern mopar sites...
Some of you already know that the 6.1 block has a bore size of 4.055" and cant really go any larger than 4.08" due to cylinder wall thickness. I purchased 5 blocks at an auction a couple years back and this one block stood out as being different. The part number is different, the color is different, the water jackets are actually from a 5.7, but it had 6.1 cast into the side of the block. I sonic tested the block and found that this block could go all the way up to a 4.185" bore and still be considered safe. This was very strange to me so I inquired with a couple of guys in the know about what I had and this was their response.
If that is the block I think it is, it used to be painted black. Of the 6 or so that were made, most were a rough 5.7L bore size with all other features finish-machined to the 6.1L print. Blocks were cast with the 5.7L bores but I thought we stayed with the 6.1L water jacket core and block material. Cam tunnel cores were 6.1L as I recall but we simply deleted the piston jet machining. Also, it seems to me our intent was to put a “P” at the beginning of the casting number, but I may be confusing that with the aluminum block.
Anyway, if this is the block I think it is, it was an early attempt at a heavy duty/race/blower capable block for Mopar with the idea that we might be able to use it in a skunkworx supercharged buzz model. Never went anywhere and they kinda fell off the table when the discussion turned toward the 6.4L variant being conceptualized.
So basically I have come across a 1 of 6 block that is capable of way more than any production 6.1 block out there. We have decided to use a 4.145" bore with a 4.08" stroke to build a 440 that will be able to handle over 1000hp and thats where we sit. Here is a pic of the block.
That is destiny.
Soo... a 440 capable of handling massive boost?
2007 Tor-Red MSRT W/ SRT group I, II & III
LMI true CAI, MMPG 87mm TB, GTP Ported Intake Manifold, Inertia Performance Heads, FRI Tomahawk, 176* T-Stat, SLP U/D pulley, JBA Long Tubes with catted mids, Custom cat-back W/ Blastin' Bob's, PT 2800, Blue tops, Getrag W/ 3.73s and CMR tuned by Brent at DTP.
11/11/11 11.504 @ 118.00, 1.598 60' W/ 315/35/17 NT05R DRs @ 20lbs, 93 oct pump gas, 4125lbs, and a DA of -680
Does the motor already have a home or will it be up for sale?
Getrag diff. - magnaflow highflow cats - LMI - 185 tstat - custom tune from Johan - dominator TC- builder bill stage II VB and flex plate- line lock - Mopar TCM - Techo strut bar - 275/40/20 Vredsteins all the way around - ppp stage 2 heads - race warrior cam- zeitronix wideband - water/methanol kit
Where does one go about finding these so called "auctions"?
'06 Silver R/T with Road and Track on UAS
Isn't that interesting
PWR-Ported Intake/Heads/Cam-224/87MM TB
Tuned By Injected Engineering
Billy Boat Exhaust/No Cats
[COLOR="Red"]SP Chubby Sway Bars/Razors Edge Strut Brace/Pedders Bumpsteer Kit
Pedder Drop Spring/Bushings/Struts/Shocks
So that's the one!! I want to know where the other 5 are.
Personal Best: coming soon!!
I like "bastard block" written in the valley. Lol
Modern Muscle (VA), Inertia, Arrington, LMI