Looking for 451 motor opinions

[hunt2elk]

After just getting my Charger restoration about buttoned up, I am really liking the power of the 440 in it. 488 hp & 541 ft lbs. I have a #'s matching 69 Road Runner that I would like to have similar power, or fairly close. When doing a little research, it seems that a 400 block with a 440 crank is a good reliable combo. I would pull the original 383 and set it in the corner. 1971-74 400 blocks are the best? I have a 440 steel crank that could be used. Looking for opinions on a build from you who have done this. I want to use the hp factory exhaust manifolds. I will put on new TTi 2.5" mandrel bent exhaust with Dynomax mufflers. I am happy with the Stealth heads on my 440 so am not opposed to using a pair for this build, unless there is a better option (I have a pair of extra 906's). I will not use another RPM intake because of height, so am thinking maybe a Holley Street Dominator, although this is a single plane. I like the Holley 770 Street Avenger on my 440 so would be happy with another on this motor. Mopar Performance electronic ignition.
So the car is a 69 RR, 4-speed, 3.91 rear (I wouldn't mind going to a 3.73 or 3.55 someday), 28" rear tires. I want a reliable motor capable of running on 91 octane pump gas. The car will never be raced, but looking for some spirited stoplight to stoplight action with plenty of torque. I have a solid cam in my 440 and have no problems using another in this motor. What do you guys think?

 

[Darter6]

About 10 years ago I did a 451 "B" engine.9to1 compression. 88cc Edelbrock Heads.Hydro Comp Cam (It was a prototype "Thumper" that they were soon to come out with.) Stuck it in a 65 Belvedere with a tremec 5 speed and 3.73 gears.Would run on pump gas,even 87 with some timing taken out of it.Easy 20 mpg, Took it on 2 Power Tours and coast to coast twice, put 30,000 miles on it before sticking in a torqueflight with a 3500 stall and 4.10 gears and went racing with it. In full street trim it ran 11.90's all day long.Did a interview with E-Booger of Mopar Action at the Nats. His opinion of the 451 it that it is the best combo on the market. Now that was 10 years ago.Now The engine resides in a 73 "Cuda with a Passon 4 speed overdrive that did another Power Tour in 2007 and is still being driven today. Just a thought........

 

[747mopar]

I built a 451 (456 in my case) for my Charger and after finally getting the setup really close today I'm really happy with it (runs really strong). Mine was built with a 73 400, 71 440 crank and rods, KB flat top pistons (had to be milled flat), Comp Cam 264 duration 501" lift (very streetable setup), ported 452 heads with the larger Ferra valves, Eddy RPM intake and an 870 Holley Street Avanger Vacuum sec (again for street driving). Cost wise, I built mine for around $4,500-5,000 and using the Stealths wouldn't add any to the cost because I have $900.00 in my 452s. In my case I couldn't afford the Edelbrock RPM heads and despise China so I stuck with the good old factory heads which after a home porting job flow well enough to handle up to a .600 lift cam but it still would have been wise to go with the Eddies. The only special machine work needed was clearancing I believe 4 throws of the crank (I did myself in the lathe in about 15-20 minutes so don't let them rip you on that) and turning the mains down to the 400 size. I like it so far

 

[Garys1969RR]

My 451 runs great, and I plan to build another one some day. I like using the 6.76 rod from the 440. That allows you to use a short compression height piston. Mine weigh only 550 grams. C/H of 1.320". Looks like a high revving small block Chevy piston! OOPS, did I say the C word? Lol. Yes I feel that the 451 is the best way to go.

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The earlier blocks have larger amounts of cast iron around the main saddles. Supposedly stronger.

 

[747mopar]

Yeap, my KBs actually have the wrist pin intersecting the oil ring but use a stiff support ring to support the ring.

 

[hunt2elk]

Did you throw your motor on a dyno Devin? Just curious as to what kind of power this setup makes.

 

[Darter6]

Here is another, 451, stock 346 heads, Iron intake,600 AFB, 484 purpleshaft. Auto with 3.73 gears.
TTI headers and full exhaust.
Owner wanted it to look like a stock 383 with air. Chassis dyno pulled 346HP at the wheels.Heads, intake and carb limited high rpm. Car ran high 12's but can drive anywhere in comfort like a new car.

 

[hunt2elk]

Chassis dyno pulled 346HP at the wheels.Heads, intake and carb limited high rpm. Car ran high 12's but can drive anywhere in comfort like a new car.

What do you think that would translate to crankshaft hp?

 

[747mopar]

Did you throw your motor on a dyno Devin? Just curious as to what kind of power this setup makes.

I wish I could have but I have to keep myself on a tight budget and dyno time isn't cheap. My last car was a 450hp 82 Grand Prix and after today I'm quite certain the Charger would eat it for lunch. I bought a book written by the guys at Muscle Motors in Michigan that was very helpful in my decisions. It's not so much that it's magical combo as much as it is combining the bigger bore (400) with the longer stroke (440) and ending up with a lighter, shorter and more stout motor (they claim the 400 is a solid block to work with). Your getting more cubes for cheap, shaving a few pounds and height, and getting a lighter rotating assembly with the shorter pistons. Unlike the retarded 383 chevy stroker where you take a bigger bore and stroke motor and put the crank in a smaller bore motor with the Mopar it's a win, win, win, situation.

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I can get the name of the book if your interested but I think it was High Performance BB Mopar or something like that (sorry, it's at the garage right now). Found it http://static-hp.com/store2/images/uploads/big_block_mopar_performance_book.jpg

 

[Darter6]

Crank vs rear wheel.? I know there is a percentage equasion out there. But don't really know.

 

[Challenger340]

After just getting my Charger restoration about buttoned up, I am really liking the power of the 440 in it. 488 hp & 541 ft lbs. I have a #'s matching 69 Road Runner that I would like to have similar power, or fairly close. When doing a little research, it seems that a 400 block with a 440 crank is a good reliable combo. I would pull the original 383 and set it in the corner. 1971-74 400 blocks are the best? I have a 440 steel crank that could be used. Looking for opinions on a build from you who have done this. I want to use the hp factory exhaust manifolds. I will put on new TTi 2.5" mandrel bent exhaust with Dynomax mufflers. I am happy with the Stealth heads on my 440 so am not opposed to using a pair for this build, unless there is a better option (I have a pair of extra 906's). I will not use another RPM intake because of height, so am thinking maybe a Holley Street Dominator, although this is a single plane. I like the Holley 770 Street Avenger on my 440 so would be happy with another on this motor. Mopar Performance electronic ignition.
So the car is a 69 RR, 4-speed, 3.91 rear (I wouldn't mind going to a 3.73 or 3.55 someday), 28" rear tires. I want a reliable motor capable of running on 91 octane pump gas. The car will never be raced, but looking for some spirited stoplight to stoplight action with plenty of torque. I have a solid cam in my 440 and have no problems using another in this motor. What do you guys think?

Deja vue here.... but we built a pump Gas "438" 383 block based combo, pretty much the same as you are looking at, for a Customer's '69 Road Roach 4 spd W/3.55's about 3 years ago.
He LOVES it !
Even with 28" Tall Tires on the 3.55's, it just PULLS HARD anywhere !

Stealth Heads
Flat Tappet Solid(used XS282 Comp)
stock 440 Forged Crank
527 HP @ 5400 rpm with 555 Ft/Lbs Torque
It was Dyno'd on Pump Gas(91 Octane), this particular run used VP113 for a test because he also has a Racecar and wanted to try it(use up some of last seasons old fuel)... didn't make dick for difference though.

 

[Herr_Poopschitz]

Crank vs rear wheel.? I know there is a percentage equasion out there. But don't really know.

Approx 20%, so around 420 hp.

 

[Gpuller]

Gonna have to be careful, that 451 will out run your 440, then your gonna need more power in the Charger. Vicious cycle...
With a B motor I wouldn't think you'd have clearance problems with the Performer RPM.

 

[hunt2elk]

Gonna have to be careful, that 451 will out run your 440, then your gonna need more power in the Charger. Vicious cycle...
With a B motor I wouldn't think you'd have clearance problems with the Performer RPM.

I was thinking about that also. It might be a good thing though as I don't know if I want my wife driving a faster car than me lol. You are probably right about the RPM intake on a B motor. I guess I need to decide if I want to use the factory unsilenced air cleaner, or if it will be to restrictive for the motor.

 

[Gpuller]

Yeah don't want the chicks driving a faster car. ha ha ha
The factory unsilenced air cleaner will probably be less restrictive than a drop base and short filter.