400 vs 451

[MAXINE-70]

okay, so a buddy was asking....since he has a 400 engine and wants to build it for a fun street toy, which will run better for a street beast..... the 451 stroker, or the similarly equipped 440? i figure that everything being equal, the stroked 400 will outperform the 440, but marginally. factor in the extra machining costs and piston costs of the 451, and the 440 starts sounding better. i debated on this 5 years ago when i built a big block duster. i chose the 440 due to building costs. what kind of power differences are we talking here, all else being equal (cam, heads, intake, carb, exhaust, compression, etc)? thanks!!

[Cudadrag]

No contest The Short Deck 400 to a 451 will out perform the 440. The weight difference of 65 lbs and the 2000+ grams of recipticating weight reduction is just too much to make up with the 440. Unless you are looking for max cubic inches in a max build the 451 stroker is the better choice.

I would not build a RB motor unless its a hemi. I'm that sold on the short deck B block.

[ehostler]

If I'm going to lay out the cash to stroke an engine, I will stroke the 440 up to 500.

[87DakBuilder]

This topic was debated in an issue of Mopar Action, a few issues ago, they said that if your plans was to stroke the motor, and money wasn't an issue to go with the 400 B engine, as there really isn't much out there out performing it. However is you want a radical engine for the stree and money is the issue, go with the 440 RB block, and you can make big streetable power for a fraction of the cost. I'm not sure which is better personally, as I've only been in cars running a 440. My Dad's 69 R/T run's low high 9's/low 10's and it is an all orginal metal car. So I'm probally partial to the RB blocks. The more I research the capabilities of the B block the more excited I get though. Good luck in whatever you choose, as long as it is mopar.

Jay

[mopar_nocar]

a 400 would be a fine "fun street toy" with out any real effort or machine work. put .030" over 440 pistons into the 400 (if its standard bore, adjust the oversize as needed to fit yours), port and polish the heads get a decent cam and you've got plenty of power to do what you seem to want.

there are other ways to build the 400 low buck with lots of power. and with the favorable rod length to stroke ratio it'll last forever!

put decent gears in the rear end and hold on.

sb

[George G. Leverette]

A low deck stroker is a better engine for an A-body, the 440 would be more suitable for the B-E Bodies.

[Cudadrag]

The B-block fits nice with the A-body and headers are easier to deal with. If you bore the block 40 over its the same as 60 over on the 440 so pistons is no problem (and yes the 400 is the largest bored block chrysler ever produced) match that with the 440 crank (crank work will be needed to fit the 400 mains) I run Ross 10.5:1 pistons (using the 400's rods) and get 500 horse and a high 10 sec Duster on pump unleaded. None of my 440's performed this well or was able to hold 7000 rpms (on a solid lift 312@ .590 lift purple grind cam) Head work is no different then any big block.

I have heard the arguement "Why not go to a 500 ci RB if you want a stroker." Well the 4.150" to make the 500 RB can also be used in a short deck design to 511 ci. The 4.150 is an after market Mopar Performance crank and is $$ more then the 440 3.75" that the 451 uses.

I believe the short deck 451 is a big block that acts more like a small block. If I was to up the compression (with a change to the cam) sub 10 seconds could be had. Also the over all cost has been less then any 440 I have had. Edelbrock put out a new B-block line of sight 383 Victor manifold that noticably out performs Mopar's M-1.

If you have an A-body its a no brainer. I have not tried with an E or B body. I know it would be lighter and you would have more room if you used the 451 design. Headers may be a little more diffecult. I have an E-body 1970 Cuda that I was planning to use 426 hemi. But the Duster's 451 is making me re-think engine choices. Keith Black makes an aluminum block 440 short deck ( 9.98" deck height) that can use stage 5 hemi heads. That setup may be the best of all worlds (4.50" bore and stroke to make a short desk 573 Hemi) There are bigger and bader setups if one was to go REALLY nuts.

Just my opinion!

[greasydonkey]

youre the second guy ive heard say you can use oversized 440 pistons in a 400 stroker motor. i wasnt under that impression. i thought that the stroker pistons needed the wrist pin higher, and therefore a 440 replacement piston wouldnt work. so whats the real deal here? bore the 400 .010 and use 440 .030 pistons, or buy a set of stroker-intended pistons? im assuming if you use the 440 pistons that youd obviously have to use the shorter 400 rod too....

[dart joe]

The only extra $$ you will spend on the 451 is having the crank turned down, a good set of 440 pistons. (ross, wiesco, diamond) are the same price as the 400/451 pistons, so there is no extra cost there, i've built 3 440s, they ran good, but by far any 440 that has the same combo as mine will not stand a chance, you ain't felt torque till you build a 451 over a 440. My 451 is just a engine.

75 duster, race weight 3070
400/451, ross 10.25. 440 steel crank, 440 rods
906 heads, stock size steel valves
comp solid, 529/543 250/256@ 50 108 LSA. 1.5 rockers
M1 single, 750 proform.
411 gears, 4100 stall, shift at 5800-6000. wait till winter
Best in summer air, 10.91 @ 122.25
Best 60 ft. 1.51

[Cudadrag]

In building a 451 you don't use 440 pistons (at least I didn't, and yes I believe the 400 pistons pins are higher) it’s the rings. I used Ross B-Block stroker pistons (Ross had pistons just for this build) with 440 60 over rings. (For the life of me I can't remember whose I used, but I do remember A lot more choices if you use the 400 40 over bore which is the same as 60 over on a 440)

I also agree with Dart Joe. Dollar for Dollar the 451 has much more noticeable torque then a comparable bored 440.

Hope this clarifies

[Aspenj2002]

Hands down the 451 build is the better way to go. The pistons aren't anymore expensive than 440's (you are going to have fresh bores aren't you?) The cylinders are shorter and therefore stiffer=better ring seal=better power. The 400 block is lighter but only by about 35 lbs. I built one about 4 years ago and with the 400 rods, steel crank, KB pistons,hughes 5256 solid cam,ported 452's by me,m1 single plane-1 3/4" headers,750 dbl pumper, pump gas I achieved on a Superflow 901 533 h.p @ 5600 rpm and 559 ft/lbs @ 4200 rpm. This engine truly was a bigblock that acted like a really big small block! On the street with 3.91's stock converter in an f-body INSTANT rev limiter (6000) every time-what a blast. Build the 451 and never look back.

[23T]

You can build a tire shreading pump gas 400 with-out going to the $ of a 451 but I would go 451 over a 440

[greasydonkey]

someone clear up the 440 piston in the 400 stroker issue for me, please. if i remember correctly, ,the 440 block is about 3/4 inch taller at the deck than the 400, so it seems to me that if i use 440 crank, rods and pistons in the 400 block that the piston is gonna stick 3/4 inch OUT of the block at TDC. im thinking the 451 needs pistons MADE for only a 451 stroker....thanks!!

[dart joe]

You use 400/451 stroker pistons, ross did there homework on the 451, i've never heard of using 440 pistons, the stroker pistons are short, alot shorter then a 440 piston, when they did the final balancing on my 451 with the ross pistons, the machinest was surprised how close everything was to balancing out, thats why i would go ross. you can either use the 400 rods or 440 rods, heres there sight.

www.rosspistons.com

[dodgezilla440]

400 block + 440crank turn the mains down to 400 specs preferably good steel crank stock length 440 rods +custom piston the over square 400 + the stroke makes a qwiker higher reving combanation and is very dependable just add a good cam 214 and 181 valves with your heads 906 open chamber or maybe a set of 915 or 516 closed chamber heads depending on which piston you use add a m1 intake and your ready to go moooooparin.

[dart joe]

I forgot to mention you have to have the counter weights on the crank turned down also , it usually cost about 120.00 so total extra cost to build a 451 over a 440 will set you back about 250.00, well worth it.

[Rug_Trucker]

Isn't another advantage of the 451 a faster revving lighter rotating assembly?
From what I've read else where the weight is about the same between the two. 400 has thicker webs where the crank is. I was going to stroke a 383 til I discovered it is cracked from being frozen. It was something I brought from Tennessee.

[orangecrush]

Here is my 400 combo I posted in an earlier thread, and it is not a stroker. However, I think that Manley discontinued these rods.

am almost done with my 71 Challenger R/T. I am currently putting in a new trunk pan.This is my first post on here but I sure do read a lot of everyone's posts. I am saving my #'s matching 383 so I built a long rod 400 engine with a 383 forged crank . It is a 400 Block .030" over, Ross Flattops, Manley H-beam 6.965 Hemi length rods, block is "0" decked, with ARP main studs, 1/2" Milodon pickup and low profile pan and windage tray. Camshaft is Reed Cams Solid Roller .597/.608 lift, 290 deg. intake, 292 deg. exhaust advertised, and 254/258 @ 50. Lobe separation is 112 Deg. and is installed @ 107 Deg. Heads are Edelbrock that have been milled to 71cc and cleaned up intake ports and bowls polished. Comp Cams Pro-magnum roller rockers. Head gasket is Felpro PT8519 and intake is Performer RPM with an AED worked 750 Holley DP. Headers are 1 7/8 TTI with 3" exhaust system with Dynomax Ultra Flow Mufflers. Fuel Pump is Carter Hi-Volume Mechanical. New tank with 3/8 pickup and line. Lakewood Bellhousing, with Mcleod Street-twin B&B clutch, A-833 Transmission, 8.75 3.55 Sure-grip. MSD Pro-billet distributor and 6a box. Rear tires are going to be 275-60-15, probably BFG or something. This car is going to be mostly street driven and my question is am I going to be happy with this combo? I know that it will have a pretty nasty idle, but that's okay. Thanks.

[mopar_nocar]

granted if you wish to spend money and time hunting up the parts (if you don't already have them) build the 451.

to reiterate an earlier post: you can make a GREAT street 400 w/o the cost of the stroker. you can use B rods and oversize 440 pistons or do like i did, and mill the block to get compression. (i milled my block .100) put on some close chambered heads (to use 93 pump gas) or open chamber heads (like i did to use 89 gas) and go tear up the asphalt.

i used a stock cam and manifolds. my RAMCHARGER acts like its got a rocket in it. what would an A body feel like? i plan to find out this winter. i've put together another 727. i have another block milled. as soon as i get my crank's in i'll start assembling another motor. this one will have the .509 MP cam in it. should be interesting.

sb

[greasydonkey]

i figured it needed 451 stroker specific pistons. next question....

do you HAVE to have the counterweights turned down, or can you just notch the cylinder bore bottoms to clear the counterweights?

it seems theres two ways to do everything. some say to cut the 440 mains down to 400 size, some say to line bore the block mains to fit the 440 crank. some say to use 400 rods, some say to use 440s.some say to notch the bores to clear the 440 counterweights, some say to turn the counterweights down to clear the blocks bores.

whats the best way to go, from you guys who have actually DONE this?

thanks!!

[Cudadrag]

My 451's 440 crank was turned down so to use 400 mains (and so were the counter weights which was done for clearance and balancing) my understanding is that this way reduces rotating weight. Also it appears to be better to make the crank accommodate the 400 then trying make the 400 accommodate the crank. I'm sure there is another design but this works well in my pump 92 octane Duster. I used the 400's rods. I used Ross 10.5:1 pistons that are shorter and made for the stroker build.

I did not do the machining and am not an engine builder, but more of an engine assembler. I used a set of 452's that were polished and ported with 214/181 stainless valves. My cam is 312 degree .590 lift purple grind with solid lifters. I am currently running a Holley 850 dp with a M-1 intake, but will be upgrading to the new Edelbrock Victor 383 and Holley's HP 950.

I hoped I explained well enough. I was under the impression there was only one real 451 build. But now that I think about it one could modify the block to use a full 440 crank and mains. I would think this would be risky. I would rather mess up a crank then a sonic tested block.

Just my thoughts.

[dart joe]

Like CudaDrag said, thats the basic 451 stroker build up, i used 440 rods, either way, you can use both, theres just the difference in pin placement between the two rods. basicially what your doing is stuffing 440 internals in a 400 block(for the stroke). the advantages are the lighter rotating assembly(440 crank turned down and counter weights turned down) lighter pistons, and the larger bore in the 400.

[451Mopar]

The use of stock cast pistons in stroker 400's was done way back in the late 1980's and documented in Chrysler power magazine.
I think the used a stock 400 piston with the 440's 3.75" stroke crank and 400 length rods. This worked OK, but at sustained high RPMs they pulled the piston pin right out of the piston!

For power, both the 440 and 400 stroked to 451 can be made to produce the same power, and given equal quality parts, they actually cost about the same to build. Usually if you have a 440, you would want to rebuild it (for high performance) with lighter light weight pistons using the lighter 0.990" piston pin and aftermarket rods.
If you don't have a big block, the 400's are alot cheaper to buy than a 440, so what you sane on the block can be spent on the 440 crank.
Because the 451 stroker pistons are really light you can use reconditioned 440 rods and save a few bucks, but aftermarket rod prices are getting so affordable that they may be a better choice even though I have the 440 rods in my 451 and have been driving/racing the car for over 9-years with 6500 RPm shift points and several chassis dyno runs upto 7,000 RPM with no problems.

My next project may be a 500 cid stroked 440, but I want to use 7"+ length rods.

[dart joe]

451Mopar, whats your combo on your 451, whats it in and what kind of ETs are you getting?