I'm curious are there any R4 blocks available. that can be used with a P5 cylinder head.... also looking at rocker gear possibilities. And if anybody knows the bore space of one of these engines.it would be helpful... thank you ahead of time..

I think that is a wedge head block. p5007151ac listed as a 45/59 angle lifter. real short deck 8.58"

Because you have had such good luck with your Ritter block maybe you would like one of his x2 blocks

https://www.amazon.com/Mopar-P5007151AC-Race-Block/dp/B007NPUOCE

standard sb bore space. Those are hemi head blocks. Lifter bore spacing and angles are wrong, head bolt pattern is wrong. I looked into this also.

You could try contacting Bob Book, as he builds a few of these engines now. Don't get him started about the blocks however, he's not a fan. For the Aussie Pro Stock engines he fills them with grout and sleeves all 8 bores to get the bores stable.

P5007151AC..... there are 9 of these blocks in Warren MI depot.

...and there's still 8 P9 heads there too.

DREAM COMBO!!

Yea it's sexy but just about impossible to make go down track with heavy car.
2600-2700 ready to go down track. About as heavy as you would want to be.

All out P7 much better choice. Not as sexy but p7 on kill can make 1100-1140HP

HAS been done with SB2 and P7 just a better SB2 just takes buckets of money.

P5 on kill 1200ish and not fun to make work in a car.

440CI W8 on kill can make 1020-1040 and they make lots of torque.
Much easier to get car to work with w8 deal
3000lbs 440 w8 should go 162-164 Mph.

How fast you want to go and at what cost?

I just want to go!

you will soon.. you're in good company

The only heads to get are the Vizner stuff. All the Mopar cast heads out there, and that is only a few usually have issues with the castings. They made very very few of them to begin with. Bad A$$ stuff for sure but purpose built pieces too. The deck height is very short and bore space is stock as that was required by Aussie and Truck rules. RWR did a number of them over the years for a couple Aussie teams and Comp guys.

All the fastest Aussie Pro Stock stuff are running the Slawko Billet heads, Visner was the first to do the billet P5 head as far as I understand. You look at any of these engines and you'll see that the decks are that low, that the almost break through the bell housing flange at the rear of the block. An all out 399 ci P5 engine from Bob Book won't leave you much change from $100K
As Al stated, the cast heads have their limitations, most would crack in the intake bowl, not sure if the P9 head has the same issues.

Pretty sure the Slawko stuff are the Vizner pieces. When Waters was working with Vizner there were some things he wanted done that VIzner did not do. I think Slawko picked up from there.