400 block

Whats the largest crank I can put in a 400 block with aluminum rods. Do u guys thing that it would help block from breaking with grittle and aluminum caps

If you have a stock block & are wanting to make as strong as possible, I would be going down the BCR cap n girdle path. I have a block in being sonic tested & magnafluxed, if it passes that test I'll be going the BCR direction. I already have a 4.25 crank to make a 512. .

ive had a 540 stroker out of a 400 block.which someday ill build another,it had a 4.500 crank,and bme aluminun rods,6.53

That's what I have but adding aluminum rods.

Adding aluminum rods can take up a lot of room. I personally would have gone to the smaller Chevy rod journals if I knew I would be going to aluminum rods with a 4.15 stroker crank in an RB Mega- block. which probably has even more room than the 400 block. I had to do quite a bit of measuring, grinding and trial fitting to accomplish it . DVW helped with an old picture of the bottom inside of a mega-block he was using. Don't think any of these are a drop-in with aluminum rods, especially standard big rod journals. Bill

How is that holding up in a race application ?

What size rod journals on the crank?
I would and due put aluminum main caps and AARP main studs on all the 400 stroker motors I build and use
Forget the girdles, they are a waste of money and give you a false since of security and hope

[quote=Cab_Burge
Forget the girdles, they are a waste of money and give you a false since of security and hope [/quote]

what are you not seeing as a strong point with a cap n girdle kit Cab? These BCR units look awesome. Caps that fit snug between the webs, A girdle that mounts further out than the main studs for even more rigidity & is 1/2" thick. I'd be more inclinded to go this way than alloy caps.

That engine looks familiar
That is my 400 500" stroker that the machine shop overbalanced adding weight the the front crank throw. discolaration on crank throw from where they welded the weight in.
After running engine like that for a few races, I pulled it back apart and had the crank re-balanced where they removed the weight the other shop added.
After that episode, I bought a good scale and rod balance fixture to verify the balance on the other 440 source stroker kits which were OK.
The BCR caps and girdle are nice. The machining cost to install them is not cheap. Align bore/hone the crank bore, and mill the block/caps level was almost the cost of the cap/girdle kit.
I also had to make a custom 1/2" oil pickup, but it ended up basically just a straight tube welded to an old milodon pickup cup/screen, Using the milodon low profile 7-quart oil pan from my old 451 stroker engine.

That set up does look awesome. Almost gives a new meaning to the term 'wedge'. Just a quick question though... Do the sides of each cap require machining where they meet the block, or is there some clearance in there?

look closely at that girdle, where does it add stiffness to the block?
It may add some strength to the main studs from moving front to rear but is that useful and needed?
My thinking is the 5/16 oil pan rail studs do nothing to help the main caps
Buy a better block instead of trying to patch up a stock block, especially 440 blocks

Hi Cesar, how is the weather in Florida?

Last time I was there in December 2010 it was snowing lol.
Snowing here now so I’m thinking of coming over ASAP.

Best Mopar block is the 71-72 400 casting.
So a great place to start for a stroker.
My Moparmate ran a 4.500 crank in his 400, it was over 1000hp...

Yes if it’s a long lasting block it has to be after market 4 bolt mains.

I’m sure Ali caps are a bonus and a girdle too.

We have used the 4 bolt STEEL ‘program’ caps for nearly twenty years!
Lots of machine work and hard to find good machine shops now...

There is a bit of clearance between the side of the cap and block, but the block casting was cleaned up also.
With the oil pan gasket, you can't see the nuts bolting the girdle to the block. The girdle holes for the oil pan studs are counter-bored so the nuts are below the oil pan gasket.
Because the oil pan rail and caps are milled flat, the girdle is right on top of the caps, and the caps bolted to the girdle on the outer wedge part of the caps (along with the normal main cap studs.)

More pictures on the web site:
https://www.bcrproducts.com/caps_and_girdle_system.html


After doing all the mods to the stock block, the costs started getting up there (around $1,600 for the caps, girdle, and machine work), but still way less than an aftermarket block which are around $5,000 these days.
https://www.manciniracing.com/engineblocks.html
https://billmitchellproducts.com/product-category/engine-blocks/mopar-big-block-2/

The girdles may provide some lateral stability but darn little virticle. Look at the block structure of the latest performance engines. Deep skirted blocks that do something. If I was going to build a girdle it would have a very tall structure , like three inch or maybe even more. Rather impractical though, hanging a three to four inch tall girdle on the block to transfer more of the load to the pan rail, which might not be strong enough to hold up . But it would help resist virtical forces a lot.

All those girdles are gimmicks in my opinion. All you can do is periodically check for cracks.

If I wanted to make the most power I could using a stock block, I'd probably stop around 4" or less and put a long rod in it.

If you decide to use the girdle and aluminum cap set up, Laz at Mesa Balancing did the machine work on my RB stroker with the the BCR parts. the only thing I can complain about is cap growth and low oil pressure if i let the idle go below 800 rpm. i did change to a Milodon 21814 pump which helped some. Oil pressure over 900 rpm or cold any rpm is fine.

Do you know what the main bearing clearances were set at?