BB Swap

[Jerry Ikemire]

I have a line on a 0.30 over 440 with a 727 trans at a good price. My car is '73 Challenger with 318 and 904. I understand there will need to be some suspension changes and possibly tunnel alterations. Has anyone here made that swap that has some advice?

 

[SFEbody]

I went from a /6 to a 440HP, no mods to tunnel but did convert to R/T suspension and power disk brakes in front.

 

[rklein71]

You will need a different driveshaft as well.

 

[moparlee]

As stated above the tunnel is ok, but you will want the heavier T-bars.

 

[moparleo]

Actually, quite a few of things. Besides the driveshaft, engine harness, Throttle cable, linkages, brackets, Radiator, the usual hoses, belts, pulleys, brackets, trans lines, exhaust, . 3/8" Fuel lines if you want it done properly. Heavier torsion bars, shocks, brake upgrade if not already disc. Depends on how you intend to drive it and how safe you want it. They used HD parts on the bigger engines for a reason. E-bodies are nose heavy already and the extra weight does not help with braking and handling .

 

[340challconvert]

Do not forget the leaf springs, which were HD; some bb 440 cars used 5 leaf/6 leaf springs to handle the torque of a 440. At any rate, you should eventually address the rear leafs with a modified 440.

 

[HooToTheCore]

I did the same swap on my '70. Changed the driveshaft, changed the torsion bars, added stock front sway bar. I have a 8 3/4 diff which has the small yoke, my driveshaft used the larger u-joint. For the rear u-joint, I used the one that converted from the larger size to the smaller size. I've still got the drum front brakes and they work fine (will convert at some future point). Also, since I did not want headers, I used the stock high performance manifolds and installed a stock dual exhaust from Accurate. I still have the 5/16 fuel lines, no problems. I did go with a 26" radiator (probably the biggest modification).

As far as wiring, I only needed to extend the temp sensor wire. Also may have changed the battery to starter cable. Oil pressure was fine, alternator was fine, coil was fine. I bought a 440 throttle cable and had the cable linkage already on my engine.

That is all I did. I don't race, just have fun driving and showing off the BB engine.

 

[Dodgeboy]

I swaped my 318/904 to a 383/727 in my '74. I had to change rad (overheating issues) and engine mounts. I installed a Lokar kickdown cable as i didn't have the BB one and the 318 one (even thou i lengthened it), didn't really work. Throttle cable works fine. I used the 318 driveshaft for a bit and eventually put in a proper lengh/quality one. I've never touched the torsion bars but did replace rear springs. I was fore-warned about body flex so i installed subframe connectors as i have a "solid/dog gear" posi unit and wide rear tires.

 

[Jerry Ikemire]

All very good information!!! Thanks guys. Unfortunately the 440/727 disappeared as fast as it was posted....same day in fact! But from what I'm reading here maybe that wasn't a bad thing..... I kinda like the 383 swap Dodgeboy described. Sounds like something I should dig deeper into.

 

[ZippyZoo]

Like others, I did the same swap on my 71 Challenger. My car came from the factory with 318/904 and a 7-1/4 axle! Definitely change to an 8-3/4. My 5/16 fuel line works fine but I did put a small "helper" electric fuel pump back near the tank to address potential vapor lock. Yes, I went with the larger torsion bars, larger u-joints, power front discs, sway bars, driveshaft and 26" radiator/fan/shroud as mentioned by others. My car came with a 22" radiator so there was a blocking plate at the right radiator core support. I initially made an adapter plate to fit the 26" radiator and finally swapped out the right hand core support plate to fit the 26" radiator. Make sure you get as many "connecting" parts, brackets (such as throttle, return spring, power steering, alternator, etc.), manifolds, yoke, pulleys, fan, mounts, etc. as possible with your 440/727 combination.
Enjoy!

 

[Jerry Ikemire]

The 440 deal fell through but the fella told me of a 383 he knew a guy was selling with a 727. I scored on that one, just need to pick it up Friday. '69 casting and has never been rebuilt. I've been reading up on the 383 and have seen the block to be a very healthy production that has been proven for 400 hp on the cheap!! I LOVE cheap (only the money aspect of it). That's the route I'm going and cannot wait to get started!! I appreciate all your advice regarding the swap and am already shopping for things you have recommended to make it successful. Thanks guys!!!

 

[340challconvert]

I've owned a number of 383 HP engines in e bodies over the years. Great engines; plenty of torque, uses the 440 heads (69-70 castings) and runs great with the old purple shaft cams. Fun to drive. JMO