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440 crank with no turned counterweights, only clearanced block, but needed chamfered counterweights

Also a 451...

I built several 431's (383 based) and 451 B's long before they were cool and long before they were overshadowed by the (now more easily affordable) 496-511; I think of them more as lighter (both in weight and rotating mass) and more compact 440 where everything seems to work just a little bit better. If you already have a 440 RB in a B/E body, I think nowadays the couple extra $100 it cost to machine the crank for a 451B could probably better invested in (in terms of more HP per $$) in improving your cylinder head flow. Simply stated, a 440RB is still a very formidable motor and when you go with aftermarket rods and lighter pistons for either build anyway (which 20yrs ago was seldom used in the apples to apples 451RB vs 451B build comparisons back then) 20 yrs ago, a 4.25" stroker crank was at least 1200-1500 so not many 511's were running around on the street....so when you take those considerations into account I think today the 451B's 'real world' advantage diminishes quite a bit. Of course I'm the first to say that the 451 is still a great motor....but with todays' affordable stroker cranks vs machining the mains CW's and sometimes opting for an offset grind 3.90/ 2.200 rods) on a 40yr old crank, it's much harder to make the case for not doing a 4.15-4.30" 2.20 journal 496-511-517; compared to a 451 it's like getting more than a whole extra 440 cylinder's worth of cubes/power and torque for really (as pistons and rods are a wash) not much more coin.

Yer wise, Wizeman. No need to pay for machine work on a used crank when new ones are so readily available. And as Chuck Senatore says, "Build the biggest shortblock you can afford."
We are living in a golden age where everything we wished for in 1975 (in terms of engines and transmissions) is available for much less than the only equivalent parts cost then.
Example: In my hometown in 1975 the local serious hot rodder built a 427 with Carillo rods and aluminum heads. The rods cost $500 and the heads cost something like $1500. In 1975 a new car cost around $5000. Now a new car costs $25000.
So if the prices were converted on the same scale a complete set of aluminum heads would cost $7500 and a set of aftermarket forged rods would cost $2500. Also, in 1975 there were no aftermarket hard parts for Mopars. None. I guess Arias or Venolia would make you a set of pistons but that was about it.
Enjoy it while it lasts!

R.

Dog,

Yeah I remember Arias would make you a 451 slug, with a .990 pin and you had to bronze bush your LY (or my prefered 383) rods. The undersize of the slug had "427" (chevy BB) cast into it.

You're right Arias and Venolia were about the only 2 Piston players that would make you one back then.

It was expensive but fun times, very 'hush-hush' back then in the pre F.A.S.T. days when we had a few very quick '383's trawling around

Everyone ( the customer ) has different needs,wants,expectations and especially budgets . I would love to sell every single customer a new crankshaft,rods and pistons.

That would be a perfect World indeed. The reality is that simply isnt going to happen. When you build enough engines as a business, and not a hobby, you find out you deal with an incredible cross section of " personalities". They have many many different requirements. This is where a builder needs to put himself in the customers shoes as if it was their money and build.

I agree that its always best to use new parts whenever possible. I recently did a 451 with stock crank and stock 400 rods. There was no need for this guy to buy a new aftermarket

crank and h beam rods. He took that money and put it into a set of Edelbrock heads. He wanted a torquey,simple drive it anywhere street car. Thats what he got.

The original poster asked some specific questions obviously so he knew more about how to make 451. Does he need a new crank? I dont know. None of us know his budget or needs at this point.

Good info here, but be careful of simply broadbrushing everyone into the same picture.

Bobby, i do agree on the 4.250 crank motors much of the time. Usually just makes sense, but again, not everyone wants or needs maximum torque and horsepower. What did thoseu 431's go in amd how did they run? What heads and cams?
I like the availability of the 383 blocks for the street/strip guys.

My first 431 went into a black 69 road runner with a 4 speed hacked trans tunnel for an e body shifter and 4.30 gears and epoxied 915 heads and that little '383' took 4x what it cost to build playin possum ( long odds) against some pretty serious street iron and trailered race cars with 'borrowed' plates.

I agree whole- heartedly and I'll always have a soft spot for 431-451's cause I cut my teeth on them after switching fromw2 small blocks.

sounds great u guy's are awesome with all this info thanks.

ok guy's who wants to grind a crank? lol but on a serious note i will pay as long as it's a reasonable price. thanks buck

Please pm me your phone number

Some good info posted. I built a low deck 451 in a 400 block back in 2001. I liked it. The main bearing journals on a 440 crank are 2.750" (nominal), and the 400 block used 2.625" (nominal).

In general, cutting the counter weights down to 7.25" diameter will clear the block. The bigger the bevel on the counterweights, like CompetitionWedge posted, the larger the counterweight diameter can be. A typical factory 440 steel crank has counterweights about 7.50-7.55" dia.

This picture shows where the 400 block interferes with the factory 440 counterweights. You can grind clearance here as an alternative.

With typical 6.76" long connecting rods, a piston with a compression height about 1.32" puts the piston near zero deck. Some specific rod lengths, pistons, and block deck heights may result in the piston down the hole (low compression ratio); so check the details (especially the machined deck block height) of the parts you plan to use:

+9.980 Block deck height (could be 9.97x after machining)
-1.875 Crank stroke divided by 2 (3.75/2)
-6.768 Connecting rod length (many H-beams are 6.760")
-1.320 Piston compression height
------
0.017" below the deck

And be sure the pistons you buy use the pin diameter to match the connecting rods you use (1.094", 0.990" common)

Examples of pistons:
Bore___CH__weight_ring pack sizes__piston pin size_ part no.
4.375, 1.320, 510g, 1/16, 1/16, 3/16, 1.094 x 2.930, 99494 Ross
4.375, 1.320, 527g, 1/16, 1/16, 3/16, 0.990 x 2.930, 99495 Ross
4.375, 1.313, 524g, 1/16, 1/16, 3/16, 1.094 x 2.930,131175 JE
4.375, 1.313, 525g, 1/16, 1/16, 3/16, 0.990 x 2.930,131174 JE
4.375, 1.300, 515g, 1/16, 1/16, 3/16, 0.990 x 2.930,K296A35 Wiseco

Check KB also. I don't know if all the above are still available, but they were stocking parts back then.

My 451 is low 700 hp, pushes my 3600lbs car 9.73to 9.85 all day. and the best news is its FOR SALE for way less than you could build it.

whats the specs if you don't mind.....

I have a 451 for sale . . . 3.45 x 4.560