'68 Big Block Conversion

[John Milner]

I have a factory 318 '68 Charger that I am getting ready to install a 440 in.  It is my understanding that the small block K frame will work.  Do I just need to get 440 motor mounts for the conversion?  What all is needed to go from the 318 to 440? 

[Ryan.C]

I converted a '69 factory 318 car to a 440 with the original K-member using big block engine mounts. 

[BLK 68 R/T]

Yes, K frame is the same, just different motor mounts for the engine. Pretty much everything else will need changed as well - exhaust, all engine pulleys and brackets are different, transmission is different, etc. What rear end is currently in the car?

[John Milner]

Thanks guys, that's what I wanted to hear.  Right now, the car has an 8 3/4 rear end. 

[GreenMachine]

Motor mount brackets from 66-72 B or C body and 71-74 E body will work.


If your car is auto, and your transmission is a 904, you will also need to shorten your driveshaft due to the 727 being longer. I just swapped drivetrains in a '68 Coronet (318/904 column shift) and a '68 Chrysler 300 (440/727 column shift). Driveshafts and exhausts were the only issues that I can remember other than extending the + coil wire and water temp sensor wire. If your 440 is '73-up, the water pump will need to be changed to the earlier style and that may cause issues with some brackets and pulleys.

[Nacho-RT74]

and radiator, and T bars upgrade and.... whatever miscelaneous part related to BB but nothing structurally, just mechanic parts


the deal with SB or BB K member is on 73 and lates

note:

not really the water pump, but the water pump housing... and also will deal with the steering pump brackets to fit it correctly higher like pre 73 engines ( that is if as mentioned, the engine is post 73 )

need to think also damper/crank pulley setup got an offset hole up to 69/70.... once again just thinking out loud without know the year of the 440 you get. With AC, water pump gets its own iddler puller up to 72 what 73 and lates didn't get... lates run a diff belt setup on these cars, so then the pulleys

[68CoronetRT]

I learned the hard way that SB pulleys/Torsion bars dont really work with the 383/440's. Iam still using the 22" radiator and it works just fine. Needed to swap out the water pump housing and buy all new pulleys to get everything to line up properly. It was a mess. I bought the car that way though, so I had to learn just by figuring everything out. First old Mopar so I've learned ALOT about this small annoying stuff. Also was able to re use the power steering pump from the SB, with the proper bracket from 440source.

[Brass]

Spicer 7290 U-joints.   

[Nacho-RT74]

OH... and the radiator core support opening

[Troy]

Lots of big blocks (well, 68-70 for sure) had the smaller 22" radiator and lots of small blocks got the bigger 26" radiator. For the most part, you got the big radiator with A/C or an axle package (I'm sure there are exceptions).

Now, bigger suspension and brakes came with the engine based on size (and there were optional packages that could break the rules).

None of these are a requirement for an engine swap - but driving around with an extra 400 pounds in front and a lot more horsepower without upgrading the brakes and suspension probably isn't terribly smart.

I think most of the "required" stuff has been covered: transmission, kick down or clutch linkage, certain wires in the engine compartment, engine accessory brackets and pulleys, driveshaft, radiator hoses(?), possibly throttle cable(?), fuel lines, exhaust.

Troy

[Mike DC]

  
BTW: There is never-ending confusion about small & big block K-frames because it was a model year difference (for B-bodies).  


The 1972/earlier cars had K-frames that were bolted solid onto the front framerails.  Those used the same K-frame for small and big blocks.  

The 1973/later cars went to rubber bushings on the K-frame.  These used two different K-frames for the small & big blocks.  

Almost nothing on the front chassis/suspension will interchange between the two K-frame designs.  
 

[Nacho-RT74]

 
Almost nothing on the front chassis/suspension will interchange between the two K-frame designs.   
   

actually absolutelly NOTHING