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Who has the best 451 crate motor with cast heads that makes 500 HP

I have NO IDEA why anyone wants/insists on a 400 Block for 500-550 hp Engine builds Vrs a 440 Block ?

I mean what's the 400 Blocks big draw ?
* the slightly lighter weight ?
* the narrower under hood size ?
* the lighter Bobweight ?

The 400 Blocks are stronger than the 440 Blocks.... but that factor isn't at play until above 650 hp where it's not 'if" but 'when' both will break eventually anyway... the 440 Blocks just sooner ?
so what's the big deal ?

And especially given most are pump gas/mufflered street cars.... remember that the 400 Engine builds are typically much shorter Piston skirts = Noisey "Piston Slap" is quite common in operation than the longer piston skirt 440 builds ?
 
Challenger340 said:
I have NO IDEA why anyone wants/insists on a 400 Block for 500-550 hp Engine builds Vrs a 440 Block ?

I mean what's the 400 Blocks big draw ?
* the slightly lighter weight ?
* the narrower under hood size ?
* the lighter Bobweight ?

The 400 Blocks are stronger than the 440 Blocks.... but that factor isn't at play until above 650 hp where it's not 'if" but 'when' both will break eventually anyway... the 440 Blocks just sooner ?
so what's the big deal ?

And especially given most are pump gas/mufflered street cars.... remember that the 400 Engine builds are typically much shorter Piston skirts = Noisey "Piston Slap" is quite common in operation than the longer piston skirt 440 builds ?
Click to expand...
It's the deck height. With today's low profile pistons? Means you get less rotating weight on the build's assembly. Meaning better efficiency per cubic inch. The first thought on the smaller main bearings was that it's weaker. But turns out they produce less friction. Thus less heat. And heat is the bearing's enemy.

The reason why 440 and to some extent the 426 street hemi was a little "Boat anchorish" right off the showroom? Was what I believe is the RB block is under stroked for its deck height. The B-block with an RB crank is a marriage made in heaven. (Obviously have to machine down for B-block use. But never the less.)

Bore a 440 .060 over and you get 451. That motor stands no chance against a B-block 451.
 
There's a confluence of small advantages that add up to a relatively large advantage.

One aspect is the bore size. It's the same argument the 340 proponents have versus the 360.

Funny how everyone applauds the 340, but no one does the same for the 400, for exactly the same reason.

As stated above, rotating assembly weight is another, plus weight of the block it's self.

All this is and more is spelled out in the "451 manifesto" available online.
 
YY1 said:
There's a confluence of small advantages that add up to a relatively large advantage.

One aspect is the bore size. It's the same argument the 340 proponents have versus the 360.

Funny how everyone applauds the 340, but no one does the same for the 400, for exactly the same reason.

As stated above, rotating assembly weight is another, plus weight of the block it's self.

All this is and more is spelled out in the "451 manifesto" available online.
Click to expand...
Good point.
 
My question still stands-

Are the small block 408/416/426 engines being sold by multiple vendors all made with brand new blocks?
 
400's are still fairly easy to find and relatively cheap in my neck of the woods.

440's are at a premium, and even 383's are much more expensive than 400's.

The biggest drawback to a 400 build is the lack of "affordable" higher than stock compression pistons.

That problem goes away to a certain extent with a 451 build, but is replaced by machining expenses.

If a company offered ready built short/long block 451's, they could leverage bulk machining costs to bring the price down for the end consumer, just like the 408/416.
 
Cojohnso1 said:
It's the deck height. With today's low profile pistons? Means you get less rotating weight on the build's assembly. Meaning better efficiency per cubic inch. The first thought on the smaller main bearings was that it's weaker. But turns out they produce less friction. Thus less heat. And heat is the bearing's enemy.

The reason why 440 and to some extent the 426 street hemi was a little "Boat anchorish" right off the showroom? Was what I believe is the RB block is under stroked for its deck height. The B-block with an RB crank is a marriage made in heaven. (Obviously have to machine down for B-block use. But never the less.)

Bore a 440 .060 over and you get 451. That motor stands no chance against a B-block 451.
Click to expand...

I've Machined/Built/Engine Dyno'd literally dozens and dozens of 451's over the decades right back to the late 70's/early 80's.... many probably before LOTS on here were even born ?
That said...
IMO, I see little to NO advantage building a 400 based 451.... Vrs a 440 at the 450-550 hp level..... and in a mufflered street car ? possibly many dis-advantages in audible "Piston Slap" from the 1.34" CD 451 Piston that nobody wants to listen to ?
 
The 451 kit manufacturers seem to still be in business.
 
YY1 said:
My question still stands-

Are the small block 408/416/426 engines being sold by multiple vendors all made with brand new blocks?
Click to expand...
I personally don't know? I'm on my 7th Plymouth. All big blocks. I've seen some nice 408s in my travels. A friend has one in his old '64 barracuda build. It raced a 2018 high end C7 Vette. Had him up to the 1/8 mile mark. The vettes 700 HP was able to reel him in. But scared the Vette owner. Lol. Vette ran mid 11. Barracuda 12 flat. And it's definitely just a street cruiser.

The 408 is a nice build.
 
COSTS MORE $ in Parts/Labor to rebuild a 250 cfm(500 hp) Cast Iron Head.... than just buying an entry level Aluminum Head(~265'ish cfm)
hence WHY....
NO Cast Iron Head 500 hp Engine Pkgs out there ?
 
Challenger340 said:
I've Machined/Built/Engine Dyno'd literally dozens and dozens of 451's over the decades right back to the late 70's/early 80's.... many probably before LOTS on here were even born ?
That said...
IMO, I see little to NO advantage building a 400 based 451.... Vrs a 440 at the 450-550 hp level..... and in a mufflered street car ? possibly many dis-advantages in audible "Piston Slap" from the 1.34" CD 451 Piston that nobody wants to listen to ?
Click to expand...
Well said.
 
Challenger340 said:
I've Machined/Built/Engine Dyno'd literally dozens and dozens of 451's over the decades right back to the late 70's/early 80's.... many probably before LOTS on here were even born ?
That said...
IMO, I see little to NO advantage building a 400 based 451.... Vrs a 440 at the 450-550 hp level..... and in a mufflered street car ? possibly many dis-advantages in audible "Piston Slap" from the 1.34" CD 451 Piston that nobody wants to listen to ?
Click to expand...
That is probably true at a lower HP target for a street cruiser build. The 440 will be less expensive. I just assembled my 451 with a new build. Gone are the very heavily ported 452 irons. Replaced with Brodex B1/BS (modest port) Gone are the stock 6.7 rods. I was able to purchase BME aluminum rods from their overstock selection for $500. Needed a little machine work to get them settled under a Ross flat top piston.

Car ran high 10 secs on iron head pump gas build. Now running E-85 on a 12.7:1 compression build. I made one attempt. Let the two step button go? And my driveshaft exploded. Err. I didn't consider the drivetrains weak link. (I'm sure this sport would be easier if I was smarter.)
 
Cast Iron heads for a factory look. I know it's easy to build 500 plus HP with aluminium heads. There were a few companies making crate 451 motors with cast Iron heads in the 7K price range a few years back. Also like the extra header room and room to change spark plugs. Excellent rod ratio.
 
No volume.

A "crate engine" implies that there is a large demand, high sales volume so that parts volume discount can be had along with machine shop efficiencies that will provide cost savings to the customer and reasonable margin for the shop.

Honestly, how many people want a 451 (i.e. a stroker), shitty factory heads and 500 hp? Feels like a business disaster.

You can build 500 hp for less than with a stroker 400, or if your going through the expense of building a stroker, why only 500 hp?
 
Challenger340 said:
I have NO IDEA why anyone wants/insists on a 400 Block for 500-550 hp Engine builds Vrs a 440 Block ?

I mean what's the 400 Blocks big draw ?
* the slightly lighter weight ?
* the narrower under hood size ?
* the lighter Bobweight ?

The 400 Blocks are stronger than the 440 Blocks.... but that factor isn't at play until above 650 hp where it's not 'if" but 'when' both will break eventually anyway... the 440 Blocks just sooner ?
so what's the big deal ?

And especially given most are pump gas/mufflered street cars.... remember that the 400 Engine builds are typically much shorter Piston skirts = Noisey "Piston Slap" is quite common in operation than the longer piston skirt 440 builds ?
Click to expand...
Agree. Most mopar fans elevate the early 400 to god like status. Yeah the webs are thick, thicker than you and 99% of the street racers will ever need. How many people over paid wildly for a "cold weather block" only to have their machinist tell them it failed a sonic test?
 
Highwaystar said:
Cast Iron heads for a factory look. I know it's easy to build 500 plus HP with aluminium heads. There were a few companies making crate 451 motors with cast Iron heads in the 7K price range a few years back. Also like the extra header room and room to change spark plugs. Excellent rod ratio.
Click to expand...
Stealth heads. Once painted on the engine block, you'll never know they arent iron. And with the lousy gas we have, it's nice not worrying about detonation. Did I mention less front end weight?
 
YY1 said:
451 "kits" requiring you to find a machine shop seem to be available from several sources.

Complete engines are somewhat conspicuously absent.

Wonder why.
Click to expand...
Pure and simple, no reliable supply of block cores. Per Johnie Mac, of Blueprint, who used to offer crate motor big blocks..... but cant anymore.
 
Challenger340 said:
COSTS MORE $ in Parts/Labor to rebuild a 250 cfm(500 hp) Cast Iron Head.... than just buying an entry level Aluminum Head(~265'ish cfm)
hence WHY....
NO Cast Iron Head 500 hp Engine Pkgs out there ?
Click to expand...
Factory cast iron heads and horsepower = vast quantities of dollars. We've recently been getting a lot of requests for iron heads in the 500-600 horsepower range!

Wow really??? What the heck, that is a lot of tedious flow bench, hand labor and dirty work the way we go about it!

After I ask a few questions about why they require those flows in iron heads I've simply been quoting them $3,800. That is enough money to make us happy to do the project.

Every one walks away thinking how dog gone good those aluminum heads are looking!

Right now we have our '346' iron headed 450 stroker not quite ready to fire on the dyno........so I guess we'll see what gives.

https://www.forbbodiesonly.com/moparforum/threads/son-of-a-gun.202631/
 
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