i'm looking at a car and it has Mopar B 400 out of an imperial. i've worked on 383's before but just minor stuff and not being a mopar guy i have a few questions. are all the B motors interchangeable other then the stuff that makes them different cubic inches (cams, w/p, intake, exhaust.....). what about motor mounting and bellhousing (can i pull the 400 and put in a 383 if i have to). also any weak points about the motors, i know the lower end is pretty stout. if i do get the car then i know i need to get some books and hit the internet hard. but any info before hand would be great. Thanks
Yeah, the 400 is a grown up 383. It'll bolt to a big block bellhousing, everything should interchange. They were the "smog motor" replacement for the 383. I've seen em punched out and stroked to 451 cubes, pretty cool. Jay
B and RB engines share many of the same parts Intakes are different and dist is .. You make a 451 with a 400 block and 440 crank
The 400 is the most overlooked motor in the mopar camp. I have done sevral but here is my favourite http://seniordragster.bravehost.com/leman.html I buiilt this one for driver practice and training in the back up car for the Nascar Returns to Lemans Project sponsored by Camtechs and Moutol oil . Engine is 9.6 to 1 compression, hydraulic cam (my own private grind) Ported 452 heads, HD stamped steel rockers. Hard Chromed crank and Eagle rods,custom Ross forged Pistons (to my specs) Holley Street Dominator intake with 800 cfm Holley carb. On the ch***is dyno in Germany it produced 408 at the rearwheels at 5500rpm and held it flat to 6250 which is what we keep the engine to since we need it to last. It is now finishing its second season of driver practice and training. A street version could be easily built for reasonable $. 408 Rear wheel HP is not less than 487 HP and not more than 510 HP at the flywheel using best case /worst case scenario for flywheel HP which i believe is a very fair way to figure it. . Or an average Flywheel Hp of 497 HP. Runs on Pump gas. have also done 460 from a 400 (Chrysler Power july 97 $1500 econo big block) a 455 from a 400. A 400 cheapy 400 cubes and a 426 from a 400 makng around 650 HP. (10.52s in a 3450 lb car. ) Good motor . has some real advantages over the 383 . The big bore is a real help in unshrouding the valves. On the 383 and 426 wedge block notching is required . On the 400 it is unecessary because the bore is already big enough.
All Mopar B motors have a 3.38" stroke. The only difference between the 350, 361, 383 and 400 is essentially the bore. The 400 is supposedly a different block casting than the rest of the B/RB family, though I can't say for sure. Depending on the year will determine whether it has a forged or cast crank. The Forged crank will have a 3.00" Thrust bearing (number 3 in these motors) while the cast cranks have a 3.25". Even the cast cranks are good though, reliable to 500 hp or more. EVERY B or RB is worth building for performance. Parts are available, but aren't cheap. They make a TON of power and are hard to kill.
Ex partner, Damon Kuhn and his 61 Plymouth, "Fugly" is running a 400 block...499 cubes and has that 4 speed car in the mid 9.60s..no bottle, all throttle. Other than a limited amount of intakes for the 400, it is stronger than the 440 block due to it's shorter deck and like already posted, the bore is huge. Many stroker combos avaliable for this engine...go for it. M.
There are two 383's ,Low block and high block ( B and RB) . The 400 is also a different block,it's smaller than a 440 block and to uninitiated it looks like a biggish small block. Just the ticket for a smaller car . There is a ton of info about building big capacity engines from the 400 , reasonable priced ones are getting really hard to find now. You really need to buy the mopar engine book ,published by Chrysler which goes into great detail on how to build your engine the right way first time.
Smallblocks have the distributor hard to reach on the rear, bigblock's have it in the right place, on the front IMO, an uninitiated person couldn't tell the difference between the smallest bigblockmopar, the 350ci, or the largest one, the 440ci. As said, the 'smogger 400ci is 'the' engine for performance upgrades. It has indeed a different, upgraded casting with thicker mainwebs. As far I know all 400ci engines came with a castcrank, easily spottable by the large offset-weight on the damper, because most castcrank Mopar engines where externally balanced.
OK guys, lots of info out there, don't need it all , just please clarify about the deck height, it's not a B or an RB? Is it in between? how big is the bore? All B motors have the same stroke? What's the stroke on a 400, and on a 440? Is the 400 an rB?(get it, little r?)
It was pretty important here when rego time came ,you were only allowed a certain size engine when repowering a car,so when the inspector looked at your 451 ,he thought.." hmmm,not much bigger than a SBC... must only be a 400 afterall "... How on earth do afford to run a BB in Holland??
The 400 block generally has heavier main webs than the RB blocks do-my 400 is a 511 with a 4.38 bore, 4.25 stroke crank and BBC rods.
Unclee, A 400-engine is a "B"-motor, which all have a 3.38" stroke like 57JoeFoMopar mentioned earlier. All RB-motors have a 3.75" stroke. There's no 'in-between' 'RB' stands for Raised Block. MercMac, I usually skimp on the more unimportant stuff like paint and such so I can afford more BB's and 440source strokerkits to up the ci's...
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