Cast iron R4 blocks

P5007151AC, R4, cast iron, for P5-P9 heads. MSRP $2530.00. 7 in the Mopar system

P5007270AC, R4, cast iron, for wedge heads. MSRP $2530.00. 6 in the Mopar system

This is an FYI only, you'll have to do your own research, on what heads to use on each.

I also posted the part numbers for the remaining 4 59* 9.200 deck R3 blocks in the system in another post....

P4876381AB (1)
P4876791AD (2)
P4876792AD (2)

one part number is Siamese bore, one isn't.

the single 6381AB is the last 48 degree block. 9.0 deck, dry sump only, no motor mounts, steel 4 bolt caps.


...and those R4 wedge blocks have some crazy low deck heights!

That's cause those R4's are designed to make big power...Been discussing a possible next project with a certain Corvette owner and it will start with and R4

Add a 1.5 in spacer sleeve all 8 cylinders and 4.25 crank 470 Cid P5 that will pull to 8500 rpms. Wow
Matt

What's the proper way to do a deck spacer? Do you put an undersized bore plate on with an undersized gasket and bore the plate,gasket, and block all together so there's no "lip" for the rings to catch on? Or do you sleeve the block with extra longs sleeves and then put the spacer on around/over too them (having a constant bore with no breaks and the deck plate giving support) and then deck it flat?

You don't want to run rings over a seam......spacer and long sleeve would be my guess.

http://www.summitracing.com/parts/sum-4853l/overview/

...but we're cheap Mopar guys.

Yeah I agree we get a lot of grief about being cheap (we're not) but that is not a real good example, that is a bone stock production 5.3 block produced litteraly by the millions, they pull it off the line and sell it at summit. Summit probably bought thousands at one time. It would be more compareable to a bare bone stock 5.7 hemi block witch by the way is a better block.

The void in the SB mopar world is not the high end blocks but the bracket and hot street guys pushing the limits of stock blocks, a T/A block with better cylinders (siamesed and more consistant) 4 bolt mains and magnum and LA mounts for $1995 would shut up %95 percent of the guys (myself included) belly-aching about the price and availability of aftermarket SBs. Most guys pushing the limit of a stock block don't care if it can be made into a dry sump, we don't care if you can mill the block down an inch shorter, we don't care about multi bolt patterns on the bell, we don't care if there is enough meat to put in 1 inch lifters, or roller cam bearings or "improved oiling" we don't need to pay top dollar for a block that can "do it all" we just want a block that can take more than a stocker can. The new victor head can potentially push 400 CFM on a 4.125 bore, a stock block ain't gonna take 750+HP for long and can't take that bore. The stock oiling can be made to work, the stock cooling can be made to work, the BPE 4.25 crank is awesome but we just need something a little better to put it all in. If I had the money I would get a block made to fit this criteria and be confidant it would fly off the shelf. The advantage a block like this would have is awesome, there is ZERO competetion, in the chevy world the is hundreds of competitors making blocks you would have to compete with, if someone made this block it would be in a market by itself. No you can not charge whatever you want for it, that has been done and failed, you could sell a ton of em if priced fairly. Chevy has several blocks like this for around $1600, slap a $400 premium on us and get er done.

Here's the quote: "Add a 1.5 in spacer sleeve all 8 cylinders"

This is a whale of a lot of work to be doing.

9" deck is what most smallblock chevies are after they get their decks straightened out. They are 9.025" stock. Siamese SBC blocks can go 4.185" and a Siamese Mopar with its slightly wider bore spacing May be able to go to 4.2 or more. Non-Siamese blocks are limited to maybe 4.100.

A 4" crank with a 6" rod and a 1.0" compression height gets 440 cubic inches using a 4.185 bore. The 434 or 440 smallblock chevy is pretty common in racing circles. That's a lot easier than sleeving all 8 holes.

But I'll never do any of that as there isn't enough money in the old till.

And that 3.78" bore $300 block is good for building a 400hp 327. That's all.

R.

The short deck chevy thing got me thinking, I would like the siamese bores, I was thinking of buying into one for that price, still a little high but whatever... then the special un-obtanium intake for a 9 inch deck, no 4.25 crank is going in with any reasonable R/S ratio or pin height, no distributor hole, special timing cover, 60mm cam tunnel adds an aweful lot to the cost of a cheap block.

What? The LS? Factory blocks and bottom ends are good to 4-digit horsepower numbers Na/Nitrous. RHS/Warhawk LS aluminum blocks are like 2500hp boosted engines. There's plenty of small bore iron blocks 4.8/5.3 pushing na and boosted pushing 650-1000hp.

I know a guy that just built a 5.3 LS with a 88mm turbo in a Mustang and it lasted only a couple passes. Ran a best of 7.07 in the 1/8. It threw a rod out of the block.

I know a guy that just built a 5.3 LS with a 88mm turbo in a Mustang and it lasted only a couple passes. Ran a best of 7.07 in the 1/8. It threw a rod out of the block.

The LS blocks I'm seeing have the cam bearing ate out of them. And they weren't high horsepower engines.

I see quite a few LS 6.0 with spun cam bearings but never a 5.3, don't know what difference but maybe a smaller cam with less spring pressure is doing it?

I highly doubt anyone is makeing 1000 NA hp with a 3.78 bore LS, bet nearly imposible to go over 700 on a max effort deal.

This is the one that impresses me

http://www.summitracing.com/parts/nal-12623967/overview/make/chevrolet

Like to see a Gen III Hemi or LA like this for ONLY DOUBLE the price and I would buy it.

There's a swedish guy that went 6.xx @ 202mph & a couple others with an LSX block too. Held together. plenty running 7's. All staying together. Go figure.

Now that aftermarket needs to get on the ball with mopar blocks. Wouldn't mind paying for a 4.20 bore all aluminum LA block.

Kent Ritter repops the intakes, how many do you want? Used all the time on Chevy 15° motors at the tracks. You don't need a 4.25 crank if your 4.185 or more bore, how big do you want to make your small block. You 440 with a 4" crank and 4.185 bore. I will sell you a 60mm ugl cam for 250.

6

I never said it would be easy or cheap!!! Lol
I agree with what your saying but let's look at it a different way.
There is enough G3 block out there to fill 98 % of the power level Mopar enthusiasts want.
IMO that hellcat block would take north of 1500 hp. I have no proof just my opinion. 6.4 head 380 cfm is pie.
Want more than that thitek.
Now what I would like to see is the P5 head on a taller block. Nobody would care about no intake or headers because at that level it's all custom.
That head simply rocks. You put together a 500 Cid small block with a head like that and look out.
Now there is another route that you could take and that's the P7.
Ritter has a block and people are putting them together.
Ritters block has some issue but so did the R3. Not making excuses but it's is what it is. And from what I'm hearing it's not casting it's machining. If this is true perhaps he should sell the block not machined to a certain extent. I don't know.
I believe the biggest problem in the Mopar camp is that there is not enough heavy hitters using our junk. Look at the crap people argue about over its not a Mopar block, its not a mopar rear or trans. Yada Yada Yada.
So there are options but people don't want to go there.
Hence no more blocks.
Matt

Matt: I have a set of the P5 "wedge" heads, and checked on the R4 blocks. As far as I know they are 8.8" deck height without lifterbore machining which are the reasons I did not buy this block. I decided to go another route; use an alu sprintcar block, and change the lifter galley (involves a lot of fabrication and welding). To stroke it spacers would do, and longer sleeves is no issue. But the problem is the headbolt pattern is also different, so I just put these heads on the shelf, maybe it can be done in my next life!! (LOL) Also checked them on R5 block, did not fit there either....

If you do this and add spacers you should do something with them to get coolant flow high enough to take away heat from the pistonrings at top dead center.
It will be a costly project unless you do the machining yourself.

First off the description on R4 block is wrong. P7 heads are a lil different bolt pattern. P9 heads have a 4.500" bore spacing.

You guys get way to caught up in numbers. You have these numbers from builds you read about memorized as if it is the gospel. Displacement numbers. I have ran from 421-468 cid with W8 heads. I love a big bore. 4.185" is small and has its limits. Current R5p7 is 4.182". Just nature of the aluminum eei block. With R3 I'd start at 4.200" 4.250" if you aint scared. Stroke simply moves the rpm power range. I like stroke. It feels better and you can shift lower. Displacement by stroke is a lot the same way except with power adders.

Long story short you dont have to build 440 cid. It just a number

The only reason I mention big Cid was to lower the rpm on the P5 heads.
I think that these heads were designed for 10000 rpm on a 358 cid.
IMO the bigger cid would lower the rpm and power ban.

Will the P9 heads bolt directly onto an A8/R4 block ? Or should I say could I remove my P5 heads and bolt on the P9 heads? What are the valve angles and flow numbers of the P9? There's not a lot of info on them.

Different bore spacing Marty, plus the bolt pattern is most likely different

$1995 blocks just isn't going to happen, the return on investment just isn't going to be there. It's all good and well saying they will sell, you're not the one kicking in the $200K and 1-2 years doing it. If you're that confident, mortgage your house and do it.

So the new R4 blocks and old R4 blocks are different? I was assuming they were the same just a different deck height. I was wanting to bolt on a good cast P5 head or try the P9's. I can't run a blower and billet heads in my class. Thanks for the info.

Sorry Marty, I've had a brain fart, I thought you were refering to the Nascar P8 heads that go on the R6 Block. They have a 4.5" Bore spacing. As far as I can tell they bolt up to the R4 blocks, Brett Miller had a pair as seen here:
https://board.moparts.org/ubbthreads/ubbthreads.php/topics/1418930/p9-mopar-head.html