Mopar R1 block

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12swinger

12swinger

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Trying to find someone that has some knowledge of the Mopar R1 race block?
Curious if they had inherent problems?
What can they usually bored to?
2 or 4 bolt main?
Would it make a decent block for a stroker build, with pretty decent heads, most likely some W5 heads I have. Possibly some W2 I have also.
I’ve stumbled on a lead on one, unused never run.
Thanks 12
 
Interesting! It’s a crap shoot with the R1, there were some on the fly changes with those during the early development of the race program. But post pics if you get to see it! But it should have capability for four bolt mains via filled in main webs and the pan rails should be cast solid as well. There’s a little information on AllPar on the small block section that is a decent introduction. The mid nineties Mopar Engines manual covers the design changes from R-1 to R-3 in very good detail if you can gain access to one.
 
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Mine is a 4 bolt main at 4.090" currently and will take 4.100", I would sonic test it before boring. Also if you're doing any clean up in the oiling system be careful where the bolt for the oil filter adapter goes in the block. The block is bored for the bolt then bored from the back, the intersection is very thin. Brett Miller told me so but I just had to clean up the intersection a little. The first blip of air to my die grinder found the water port. It probably wasn't .030-.050" thick there. I now have to run a remote filter. I can't say I wasn't warned.

Mine is 434" with Indy heads and intake, solid roller. In my 3350# 69 Dart it's gone 6.40 at almost 109 mph on pump 93.
 
The gentleman that has the block told me he had it sonic checked, and if I’m understanding him correctly it would take a .100 overbore, from a standard 340 bore size of 4.04 though he claims it’s 3.91 now.
He’s had it for years, and is pretty happy with a stroker build he has with a standard 340 block. So he feels he has no need for it.
I would want to of course stud everything, and install 4 bolt main caps, bore it close to 4.100 and hope that leaves enough room for another overbore.
Probably some of you guys have run one of these blocks, and I’m concerned if there was some problems with them?
If there an improvement over the x block I wouldn’t know, as I did find one x block, though it’s quite a distance from me.
Thanks for the info on the thin area under the oil filter area, and the resources.
 
Definitely an improvement over the X block and pretty similar to the over the counter T/A block. I personally wouldn’t go any larger than 4.06 for starters, it hurts a lot less to over bore a gouge out a cylinder instead of having to sleeve or scrap a block. Extra iron is good for ring seal and piston stability, too.
 
I’ve spoke with him twice about this block, as I heard he had one from another fellow mopar friend, and brought it up a few weeks ago about him selling it. I thought he said the TA block was a better piece and was stronger?
I had one some years ago, and couldn’t bring myself to drop it in my Dart and race it, and spray it with nitrous. Figured it belonged in a 340 six pack car that lost the engine. It did end up in a AAR Cuda.
Anyways I’ve always wanted to replace it.
I’m in no huge hurry, as I have a 372 with W2 heads, solid roller, about ready to drop in, and fire up. I’ll line the car out with that engine next summer.
Kind of always wanted to stretch the limit of one of these engines, and get close to 430-440 cubes, but was nervous about using a stock block. My machinist said I’ll blow the crank out of it.
He said he thought he had a catalog with this blocks numbers in it, he would try and dig out.
 
A 372 w/W2 heads & a solid roller cam...

A whole lotta fun right there!

I also want to go there, 420+ cubes. I have to get back to sonic checking my 340 blocks to see what I got.
 
Ok, I don't know who thinks a T/A block is better than an X is on crack.

Here is the pecking order

T/A
X
R

That's the order. For what you are doing an X would be fine. The X has a thicker deck than the T/A block, both will take 4 bolt caps. I had an X block go over 700 HP at 8000 plus RPM. Nothing wrong with that.

The R series blocks are a pain in the ***. I have one that I've nailed down to either being some bastard R1 or it's an R2. I know I have a folder with what I remember to be all the R block specs, but I can't find it. Again. So I've given the wife a standing order to find it, because I'm sure she moved it.

Essentially it comes down to this. The R series blocks all have 1 inch thick desks. Very important. They also have the front pan railed filled. Kinda a big deal. Some have magnum engine mount provisions. Some have magnum lifter valley's in them (mine has this).
Some are dry sump oiling only. Some are 59 degree lifter bank angle, and some are 48 degree. Some have Siamese bores so they can go as big as 4.220. Some can go only about 4.060 and some of the block come with a rough bore of about 3.885ish.

I've had several X blocks and every one of them sonic tested to go at least 4.125 but you have to sonic every bore on every block.

Some have 340 mains and some had 360 mains. Some had Ford mains. Some had 2 bolt caps. Some had 4 bolt caps. They will all take 4 bolt caps.

So there is some differences in them, and some commonalities.

If you can snatch up a new, unused X or R block I'd do it in a New York second.
 
The amount of variations is annoying. There is also 3 different cam tunnel sizes. And I’m sure there are more differences. There have been a few R blocks here for sale but they have something about them that I’m not willing to “Go There” with them. Just to much money for me at this point.
 
like this works
" I can't find it. Again. So I've given the wife a standing order to find it, because I'm sure she moved "
my wife "puts things away" with no idea where she put them
 
I haven’t seen it yet. Only spoke with him twice about it.
Extremely knowledgeable person he is!
From what I understand it’s a 59 deg block, with 2 bolt mains, 340 main size, cast in the engine mounts, rough bored never run, standard deck height, so my intake and heads should work W5 and M1 small runner single plane intake with the spacer.
The wife has so far been receptive about it.
I’m wrapping up a near total restoration of her 440 six pack Challenger, so that helps, plus she remembers what I said about replacing the TA engine I sold, one day. Well it’s here.
I appreciate all the info guys, so I should pull some measurements when I see it, and the numbers, and if it checks out drop the cash. It’s a fraction of what I sold the TA engine for, and I’ll focus on some main caps, and let my machinist have it, and tell me what bore size is safe. He errors on the safe side. I’m getting excited!
 
rumblefish360 said:
A 372 w/W2 heads & a solid roller cam...

A whole lotta fun right there!

I also want to go there, 420+ cubes. I have to get back to sonic checking my 340 blocks to see what I got.
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I almost relinquished a 68 or 69 340 block I have laying around with O-ringed cylinders, but I couldn’t risk using it for a stroker I’ll have quite an investment in. So I told myself just wait for a block.
Also I took some old school dome race pistons I had for a 340 and had my machinist cut them down to around a 10.5-11 piston compression distance, which got the pistons in the low 600 gram area, and some Scat rods, and I had a cross drilled 340 crankshaft for this block, balanced it all, should scream with a decent head. Best sounding engine ever a 340 imo.
I may sell if I don’t find a need, or car for it.
 
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Wyrmrider said:
good luck with that build
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I’ll take luck any day.
One at a time though, this ones going in next month.
0DA6163D-0724-433E-A3BB-648756B0B91C.jpeg
 
You should put some aluminum valve covers on that engine and send me those ugly chrome tall ones !
 
That's a whole lot of good right there, hoping your'e able to share some video of that soon. I’m right there with MBaird on the valve covers, what brand are those?
 
mbaird said:
You should put some aluminum valve covers on that engine and send me those ugly chrome tall ones !
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I’ll let you guys know on the valve covers, I am known to share my mopar stuff.
They are some new in the box Direct Connections I had laying around.
I have some blue anodized aluminum Direct Connections I wanted to use, but they hit the rockers.
 
I had a set of those on my W2 Dart Sport .
I like the stockish look. It didnt occur to me they would stop making them
 
Garrett Ellison said:
That's a whole lot of good right there, hoping your'e able to share some video of that soon. I’m right there with MBaird on the valve covers, what brand are those?
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Here’s my wife’s car I’m about done doing an amateur restoration on.
Had to hear it today, so went back to the shop today.
It starts like this in any temp, and is a great running 440
 
My favorite year of Challenger... your wife has very good taste in cars!
 
Wyrmrider said:
like this works
" I can't find it. Again. So I've given the wife a standing order to find it, because I'm sure she moved "
my wife "puts things away" with no idea where she put them
Click to expand...


I'm working on that!! She says she didn't touch the stuff but I know she did. I wasn't here when she started that project.

Sooooooooo...one day soon I'm hoping she decides to go look for it.

Ain't marriage fun?????
 
Garrett Ellison said:
My favorite year of Challenger... your wife has very good taste in cars!
Click to expand...
It was one way of dragging her to car shows, building this car for her. Plus it had the added Bonus of laying a tremendous guilt trip on her, when it comes to putting my car back together next.
Can you say 9 second street car. At least that’s the goal.
 
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