451 engine build essay

[chargervic]

I have been asked on another page of this site to post this essay. I hope it's useful to you.

Specifications for the build of my 451" B block engine which delivers 25 MPG and pushes the 3975 lb Charger into the 11's.
First of all, keep in mind that my mileage claim is for Imperial gallons, which we use in Canada. For US gallons (smaller by 20%), the number would be 20 MPG.
Another note is that I have had many years experience building Mopar hot rod engines and although I don't have any magic, I do use a great attention to detail in machining and assembly.
I first built this engine in 1999, using a 400 block, 440 modified steel crank with reduced main journals, stock forged 440 rods highly prepped, 452 motorhome heads ported and polished with oversize valves and a Mopar 284º hydraulic cam. The intake was an old 383 Torker and the carb was a stock 1968 440 AVS Carter. After a couple of upgrades to a solid lifter cam and a Six Pack set-up, I swapped the 727 transmission to a full manual shift 518 with lockup converter. This set-up got me into the mid 12's and around 22 MPG.
After a few years and 30,000 miles of listening to the tappet clatter from the MP solid cam, I decided to go to a hydraulic roller cam and aluminum heads. After 40,000 miles of 7200 RPM shifts, I replaced the bearings, but left the rings and cylinder walls alone. Another reason for this upgrade is that I am running a 518 overdrive trans and most of the time the engine is below 2000 RPM, so I wanted much more bottom end torque and, believe me, this engine has it. Over 600 lb/ft from 2000  up to 4000 RPM.
Pretty much matches my Cummins diesel.

Here is the current engine I have now:
Compression ratio: 10.55:1
440 Source Stealth heads with mild port work, 84 cc  chambers
Comp hydraulic roller cam, grind # XR274HR-10, Part # 23-710-9
Hughes Hydraulic roller lifters
Speed-Pro aluminum roller rockers (from 1999 build)
Smith Bros pushrods
Arias flat top forged pistons (custom from 1999 build)
440 Source fluid damper
Melling HV oil pump with ½" pickup  and 7 qt pan (homebuilt) from 1999 build
Factory 440 Holley Six Pack carbs ( center carb jetted down to 62's)
Edelbrock 383 style Six Pack intake
440 Source aluminum water pump and housing (modified)
The engine is all done at a little over 5000 RPM, so I use that as a shift point. It idles at 750 RPM in gear and gives 12+ inches of vacuum with a slightly rumpy idle. I have Hedman headers ceramic coated (from 1999) and a full 3" exhaust system front to back that I built myself. I use Dynomax mufflers and 3" glass packs as resonators in the tailpipes. The rear end gears are 3.91:1 Sure-Grip in an 8 ¾ housing. The car weighs 3975 with me in it at the track.
My little carb secret for mileage is simple. I put an electrically operated vacuum solenoid (minivan purge valve) in the vacuum signal line from the center carb to the outboards. I shut it off (no outboard carb action) for 99% of my driving and only use the outboards for the odd chebbie or phord that needs a lesson. I just recently dynoed another almost identical engine and we made 405 HP on the center carb only. This is lots for street use.
I use a Jacobs Ignition system from 2001, they don't make them this good any more. Plugs are gapped at .055". Champions, of course. I can run on 91 octane on the street, but use 94 at the track just to make sure there is no detonation, as I couldn't hear it if there was. I run through the mufflers, but the noisy chebbies are pretty loud. If anyone has more questions about this set-up, please contact me through the site and I would be pleased to answer.

[Bigtree]

Nice set-up, I like the carb trick! I have a 451/6-pack and you would never know it by the driveability......till you open it up....then WOW.

[fizz]

So my question is: does the 451 have some kind of advantage over a mild stroked 440, and what? This doesn't seem to be a very complicated build for the power. Neat idea on shutting off the outboard carbs

[chargervic]

There will probably be many opinions on this one, but here's mine. The 400 block is lighter than the 440, it's also an inch or so narrower, so there's more room to fit headers and change plugs. Now for the power issue. The 451 has very light pistons if you use the 440 rod length, so it revs like a 340. I have completed two versions of this program, one 451 and one 496. ( both 400 blocks). Other than displacement, they are identical in CR, cam, heads and intake system. The 451 makes slightly more power and torque, but probably because the 496 needs a bit bigger heads and cam. I think the 451 will get better fuel economy, only because it's 45 cubic inches smaller, so will need less air and fuel on each stroke. After my buddy gets his 496 on the road, which should be in the next week or so, and we take a decent length cruise, will my theory be proven. I initially did the 451 13 years ago because my car was originally a 383 HP car and I wanted the engine to look somewhat stock. That was when I was running a single 4 barrel carb. Since I've made all the other mods, it wouldn't matter now. I still prefer the 451 because of the first two reasons mostly. I guess it depends on what you have lying around for a block to start with. Really, a 451 is just a 0.050" overbored 440, so if you want the bragging rights of a 496 (500) I guess that would be the way to go. Over all I don't think it makes a lot of difference in the power unless you want to build a race engine. Both of these I've done were planned for 99% street use. I've now got around 45,000 miles on mine and I'm still happy with it. By the way, by using aluminum heads, water pump housing and pump, you lighten the engine by 59 pounds. I've weighed all the parts to prove it. If you use the 400 block and these aluminum parts, you're down around small block weight. Now the advantage in handling really shows up. With minor suspension mods, mine handles like a new Charger or Challenger, so the lighter engine really helps.
Also, for the carb shut off switch, the difference between one center carb and all three is 100 HP, proven on the dyno. Kind of like nitrous without all the risk and plumbing. I almost never turn them on. Just completed a 700 mile trip and didn't need the outboards at any time for passing.
I hope this answer helps.

[Mike DC]

    
The outer carb shutoff - Sounds good, but does the MPG really improve over just driving a 6bbl setup with a light foot?  The outer carbs are mostly felt when you're gassing it. 

[chargervic]

If you have the willpower to resist hitting the gas pedal when accelerating on an on-ramp or when passing a vehicle or climbing a steeper hill, then yes, a light foot will do the job. However, I find that locking out the outboards allows me to do all of those things very well without using the O/B carbs and thus, saves fuel. Mine still makes well over 400 HP on the center carb only, so that's enough power to still smoke the tires at will, get second gear rubber at half throttle and pass with ease anytime. My carb solenoid switch is labelled "Mustang/Camaro Switch". I almost never need it for that and only use it occasionally for "demonstration" purposes. It's still a ton of fun to drive.

[JB400]

Don't mind me, just getting some info for future use.

[skip68]

How about a picture or two?   

[chargervic]

I've tried to add pictures before, but all my files are too large to upload. I can build an engine, but I can't shrink a pic file. If you want to PM me and give me your email address, I'll be glad to send some direct to you.

[Budnicks]

sounds like a cool combo... I too like the 400 Low deck block for builds, even the 383 block for a couple of stroker builds to keep #'s matching block in the car... lighter narrower plus plus

[chargervic]

The 383 block works well, too. I did a 430" (383) a few years ago, strictly for street use. The owner wanted to keep the stock look but wanted his numbers block kept safe, so I used a date coded block with correct dated heads, etc. He was very pleased with the outcome. It performed like a 440 but with the correct 383 look.

[Challenger340]

Nice essay, makes for some good reading
And a fellow Canadian ! CHEERS ! from just down the road in the Kootenays !

I too have had an affliction for the lowdeck blocks for many decades, and the 451 combo, as far back as the early 1980's when I used to go buy, and then stuff the ARIAS S7751 slugs into my luggage for the flight back from Pomona Ca each year after the Winternationals. That was the first "off the Shelf" available Piston available for using the RB Cranks in the B Blocks back in those days, and far cheaper than the custom Venolias we had been using up until then.
We used to give the other brand owners FITS at the dragstrip in those days with our 10 second "383", (tehehehe)
Some further advantages when talking B Block vrs RB;
1.) During sonic testing, both blocks will exhibit similar wall thicknesses both major & minor thrust sides, however, the unsupported Cyl Wall length being shorter on the B's, gives a rigidity advantage vrs the RB.
2.) The Maincaps are identical outward dimension and size, however, the "Hole" drilled for the mainsize being smaller on the B(smaller main), again, just more meat for strength/harmonics dampening on the Detroit wonder metal. Bearing speeds are slower on the B as well, but not a great advantage as both are fine even with P eccentricity main bearings.
3.) The 1053 steel stock 440 cranks are far easier on the #4 maincap than custom 4340 "non-twist" pieces more commonly used. The 1053's will "winde" and "unwind" more easily during rotational strees down their length....seems to help keep #4 cap from walking around on higher output applications, although yes they will crack over time on the 440 crank factory "Rolled" Fillet.......fix for this was to grind down to a 2.200" Chub journal adding an .080" Radius Fillet with welding on either the stock 3.75" Stroke(451), or make a 3.900" Stroke(472).

Gotta Luv those lowdecks !

Bob out.   

[Budnicks]

Nice essay, makes for some good reading
And a fellow Canadian ! CHEERS ! from just down the road in the Kootenays !

I too have had an affliction for the lowdeck blocks for many decades, and the 451 combo, as far back as the early 1980's when I used to go buy, and then stuff the ARIAS S7751 slugs into my luggage for the flight back from Pomona Ca each year after the Winternationals. That was the first "off the Shelf" available Piston available for using the RB Cranks in the B Blocks back in those days, and far cheaper than the custom Venolias we had been using up until then.
We used to give the other brand owners FITS at the dragstrip in those days with our 10 second "383", (tehehehe)
Some further advantages when talking B Block vrs RB;
1.) During sonic testing, both blocks will exhibit similar wall thicknesses both major & minor thrust sides, however, the unsupported Cyl Wall length being shorter on the B's, gives a rigidity advantage vrs the RB.
2.) The Maincaps are identical outward dimension and size, however, the "Hole" drilled for the mainsize being smaller on the B(smaller main), again, just more meat for strength/harmonics dampening on the Detroit wonder metal. Bearing speeds are slower on the B as well, but not a great advantage as both are fine even with P eccentricity main bearings.
3.) The 1053 steel stock 440 cranks are far easier on the #4 maincap than custom 4340 "non-twist" pieces more commonly used. The 1053's will "winde" and "unwind" more easily during rotational strees down their length....seems to help keep #4 cap from walking around on higher output applications, although yes they will crack over time on the 440 crank factory "Rolled" Fillet.......fix for this was to grind down to a 2.200" Chub journal adding an .080" Radius Fillet with welding on either the stock 3.75" Stroke(451), or make a 3.900" Stroke(472).

Gotta Luv those lowdecks !

Bob out.   

Almost completely for got about that issue, having a smaller bore hole in the main caps, thanks for the refresher course...LOL..., done the 3.75"-3.90" stroke a few times back in the day, long before stroker cranks were readily available, netting 426ci-437ci on the 3.75" stroke or 442ci-455ci on the 3.90" & {the 400's low deck B larger bore nets you more CI's of course} 383 block in std bore 4.25" up-to 0.060" over 4.31" {great combos}, used the BBC rod size on the big end, back when I got all my stuff from Venolia or Childs & Alberts, from the late great Joe Pisano's companies... I currently have a 4.15" stroke in a 0.040" over 4.290" bore, 479ci, in my 68 RR using the original 383 block....

[MedPhys]

subscribed.

I really think I'm leaning towards the 451 instead of stroking my current 440.