I thought this video was an interesting Big Block comparo.

[SteveSS]

Chevy 454, Pontiac 455, 455 Olds, and 451 Mopar. Now it's a little weird that they used a 400 Mopar block and stroked it to 451. On the other hand, I know Pontiacs used the same block no matter what the size the v8 is. Of course, I'm interested in Mopars but my 1973 Grand Am project has a 455. Normally a Poncho 455 makes 300 hp and 500 tq. You can watch a recent video on Nick's Garage where he builds a mostly-stock one.

At the end of this video, the builder is mostly satisfied with 3 of the 4 blocks but he wishes he would have done the Mopar differently.

 

[Runner 68]

The 400 short deck Mopar block is the the absolute best block to stroke. Largest stock bore of any Mopar big block plus a short stroke. Stopping at 451 seems pretty silly to me. Go for the 512 while you're at it.
Why do you think a good 400 block is so hard to find these days? 440s are still fairly common.

 

[451Mopar]

I found out about the 451 400 strokers back in the 1980's from Chrysler Power magazine.
Back then 440's were fairly expensive, but 400 blocks were super cheap.
The problem back then was there were not much of a good selection of stroker pistons, and no inexpensive stroker kits.
Chrysler Power was running modified stock cast pistons in one of the engines, and found that they did not have the pin boss strength for high RPM.
I got my first 451 stroker around 1991? At the time I had moved, and did not know any machine shops, so I called Chuck Senator at Muscle Motors and had them build me a 451 short block with slightly dished ROSS pistons (about 11:1 compression with the B1/BS heads), and the mild 251/251 @ 0.050", around 0.600" lift Ultradyne solid roller cam. Then I ordered up the new to the market Brodix B1/BS heads from Koffels with their stage 1 porting, 1.6:1 rocker arms, sparkplugs, and cut-to-length pushrods. Bolted those together with a Milodon low profile 7-quart oil pan, Mopar M1 intake, and 2" hooker super comp headers.
That engine made about 500 HP on the chassis dyno as it was run in the car. I think shift around 6,100 RPM? I reved the engine many times to 6,500 RPM with the stock 440 crank and rods (knowing the rods were the weak point.)

As the video points out, the stroker kits avaliable now make it an easy choice to build a stroker. I think there is actually more piston selection for the stroker combinations, than for the stock stroke 400 and 440 engines. They also don't add much to the cost of the engine build.
Also, as the video points out, the cylinder heads should be upgraded if you want high performance. I agree that rebuilding the stock iron heads is almost a waste of money if looking for performance. I disagree with the video on the cost of Mopar heads being less expensive? Sure the stock replacement type Edelbrock E-Street heads, RPM heads, and 440 Source Stealth heads are fairly inexpensive, but when you start talking high performance heads like INDY, Edelbrock Victor, Mopar Stage VI, Trick Flow, and Brodix then the cost of the heads and rocker arms is likely more expensive.
I never seen the Speed Master or Promaxx heads, but I think they are a knock-off of the Edelbrock heads?
There are also some lesser know heads like BullDog, the Stage V hemi conversion heads, and modified heads from other shops (Marsh, Toth, Porter...)
Not sure if the SideWinder head is a different casting than the other Edelbrock type knock-off heads or not?

Most of the stock replacement heads use the stock intake port opening and 2.14"/1,81" valves, Where most of the High Performance use the larger Max Wedge intake port opening and usually a larger intake valve around 2.20+"
Many of the stock port opening heads can make over 600 HP. On a 500+" stroker, I believe the larger Max wedge port heads would be a better choice in a high performance application > 600 HP.

 

[SteveSS]

The 400 short deck Mopar block is the the absolute best block to stroke. Largest stock bore of any Mopar big block plus a short stroke. Stopping at 451 seems pretty silly to me. Go for the 512 while you're at it.
Why do you think a good 400 block is so hard to find these days? 440s are still fairly common.

That's what he was lamenting about. He thought he should have gone for the 512.

 

[1 Wild R/T]

Why do you think a good 400 block is so hard to find these days? 440s are still fairly common.

Perhaps the fact Chrysler made close to two million 440's over the twelve year production run versus a hundred & fifty thousand 400's over their five year production run....

400's have become popular since the advent of stroker kits but in the time they were being produced the 400 was pretty much thought of as a pig.... Low compression, heavily smog controlled... All were cast cranks...

 

[Runner 68]

Perhaps the fact Chrysler made close to two million 440's over the twelve year production run versus a hundred & fifty thousand 400's over their five year production run....

400's have become popular since the advent of stroker kits but in the time they were being produced the 400 was pretty much thought of as a pig.... Low compression, heavily smog controlled... All were cast cranks...

Totally agree Wild. POS smog motor. Bastard step cousin of the 383. But with the correct components.....killer.
I always said back in the day, I have beat down more 440's with a 383 low deck than I ever lost to.

 

[67charger383]

Someday I really want to build a 383 with the 440source 496ci stroker kit. Maybe when I blow up my current build...

a 496 with a tunnel ram and dominators would be killer.

 

[Runner 68]

Someday I really want to build a 383 with the 440source 496ci stroker kit. Maybe when I blow up my current build...

a 496 with a tunnel ram and dominators would be killer.

Find a good clean 400 block, better to stroke, heavier casting. I have two spare late 60s 383 blocks that I was saving for my Bird (On top of the numbers matching block) and my engine builder talked me into finding a 400 block. He's 72 years old and still wheel stands a 65 Belvedere half way down the track at Bandimere every chance he gets.

 

[Curiousyellow71]

I found out about the 451 400 strokers back in the 1980's from Chrysler Power magazine.
Back then 440's were fairly expensive, but 400 blocks were super cheap.
The problem back then was there were not much of a good selection of stroker pistons, and no inexpensive stroker kits.
Chrysler Power was running modified stock cast pistons in one of the engines, and found that they did not have the pin boss strength for high RPM.
I got my first 451 stroker around 1991? At the time I had moved, and did not know any machine shops, so I called Chuck Senator at Muscle Motors and had them build me a 451 short block with slightly dished ROSS pistons (about 11:1 compression with the B1/BS heads), and the mild 251/251 @ 0.050", around 0.600" lift Ultradyne solid roller cam. Then I ordered up the new to the market Brodix B1/BS heads from Koffels with their stage 1 porting, 1.6:1 rocker arms, sparkplugs, and cut-to-length pushrods. Bolted those together with a Milodon low profile 7-quart oil pan, Mopar M1 intake, and 2" hooker super comp headers.
That engine made about 500 HP on the chassis dyno as it was run in the car. I think shift around 6,100 RPM? I reved the engine many times to 6,500 RPM with the stock 440 crank and rods (knowing the rods were the weak point.)

As the video points out, the stroker kits avaliable now make it an easy choice to build a stroker. I think there is actually more piston selection for the stroker combinations, than for the stock stroke 400 and 440 engines. They also don't add much to the cost of the engine build.
Also, as the video points out, the cylinder heads should be upgraded if you want high performance. I agree that rebuilding the stock iron heads is almost a waste of money if looking for performance. I disagree with the video on the cost of Mopar heads being less expensive? Sure the stock replacement type Edelbrock E-Street heads, RPM heads, and 440 Source Stealth heads are fairly inexpensive, but when you start talking high performance heads like INDY, Edelbrock Victor, Mopar Stage VI, Trick Flow, and Brodix then the cost of the heads and rocker arms is likely more expensive.
I never seen the Speed Master or Promaxx heads, but I think they are a knock-off of the Edelbrock heads?
There are also some lesser know heads like BullDog, the Stage V hemi conversion heads, and modified heads from other shops (Marsh, Toth, Porter...)
Not sure if the SideWinder head is a different casting than the other Edelbrock type knock-off heads or not?

Most of the stock replacement heads use the stock intake port opening and 2.14"/1,81" valves, Where most of the High Performance use the larger Max Wedge intake port opening and usually a larger intake valve around 2.20+"
Many of the stock port opening heads can make over 600 HP. On a 500+" stroker, I believe the larger Max wedge port heads would be a better choice in a high performance application > 600 HP.

I think we wore the chrysler power magazine out that had the 451 build in it. That was a great magazine.

 

[33 IMP]

Find a good clean 400 block, better to stroke, heavier casting. I have two spare late 60s 383 blocks that I was saving for my Bird (On top of the numbers matching block) and my engine builder talked me into finding a 400 block. He's 72 years old and still wheel stands a 65 Belvedere half way down the track at Bandimere every chance he gets.

You stroke a 383 because you have it..... and you (generic you) probably don't have a 400.
Agreed, the 400 is preferred. The thick bottom end 400 blocks are the BEST blocks, short of an aftermarket or mp block, to build a stroker with. Better/stronger than a 440 block.
(But the .060 over 383, with the 4.25 crank is exactly the same b&s as the BBC 496 that the Chevy guys love.)
By the way, the Chevy won that comparo, cause the LS-6 heads flow about 100cfm more than the (probably)452 heads, and probably 50cfm more than the Olds or Pontiac.

 

[Photon440]

On the other hand, I know Pontiacs used the same block no matter what the size the v8 is.

There was more than one deck height for Pontiac blocks. The 301, whether turbo or not was a short deck engine, and so was the 1980-81 Pontiac 265.

 

[Runner 68]

You stroke a 383 because you have it..... and you (generic you) probably don't have a 400.
Agreed, the 400 is preferred. The thick bottom end 400 blocks are the BEST blocks, short of an aftermarket or mp block, to build a stroker with. Better/stronger than a 440 block.
(But the .060 over 383, with the 4.25 crank is exactly the same b&s as the BBC 496 that the Chevy guys love.)
By the way, the Chevy won that comparo, cause the LS-6 heads flow about 100cfm more than the (probably)452 heads, and probably 50cfm more than the Olds or Pontiac.

You are correct sir. That's why I said "correct components". For starters, TrickFlow 240s going on my 400/499, among many, many other "things".
The point is that a properly built short deck is pretty tough to beat.....383 or 400.
I think we agree.