K member/Big block swap

[Steven73SE]

Ok guys working on my 73 charger project, finishing up getting the body patched on it, and getting ready to put the rear end and k member back in it. The car was originally a 318 automatic, but i found a 440 and 727 big block transmission for sale in my area, and was looking at doing a swap. I've done a bit of research on it and found that the motor mounts are different, so whats a better option, getting a new K member or the conversion mounts? Also if anyone can give some extra info and clarify what else must be done to do the swap? I have a rallye dash out of an SE and a hurst shifter, what will it take to make these work with the big block? Also, I was looking into tubular k members for some weight savings and added room for headers, and couldnt find one for a 73 B body. I found them for earlier models and for E bodies. Any suggestion on this? Good idea or bad? Is there one available for the big block? Will they support one, and can they handle a mild street built 440? I also have an 8 3/4 rear for the car, not sure what the gear ratio is.

 

[slepr1]

Tubular K members are available from Control Freak and most likely others. The sky is the limit on what you want to do and how much you wanna spend. My philosophy is if I'm going to keep the car for my personal enjoyment I spend the money and make it my own. If I want to flip it in a few years I'll be more conservative.

http://www.freakride.com/product-category/make-model/mopar/b-body/

If you want to save some money buy a used k frame, sandblast and powdercoat, install new bushings and such.

You will need to upgrade your tortion bars too. I know the 'search' feature on this site is a bit awkward but this topic has been talked about many times. Do a search...lots of great info.

 

[YY1]

Depends on what T bars are currently installed, and desired spring action.

Factory BB 73 and up cars had part of the inner fender cut out. I believe for exhaust manifold clearance.

I'd like to know if anyone has successfully put a BB in an SB car without cutting that panel...by using headers.

You will need to extend some of the wires for the gauges, lights, wipers, and temp controls to use a rally cluster in a non rally dash.

Do you have all the parts to the slap stick shifter? Most people forget the bracket that goes on the bottom of the trans.

 

[Steven73SE]

Depends on what T bars are currently installed, and desired spring action.

Factory BB 73 and up cars had part of the inner fender cut out. I believe for exhaust manifold clearance.

I'd like to know if anyone has successfully put a BB in an SB car without cutting that panel...by using headers.

You will need to extend some of the wires for the gauges, lights, wipers, and temp controls to use a rally cluster in a non rally dash.

Do you have all the parts to the slap stick shifter? Most people forget the bracket that goes on the bottom of the trans.

I have a 1973 charger SE that had a running motor before it was parked. The body was in terrible shape but everything else was in good condition so I have the wiring harness from it, as well as the complete shifter assembly. It's actually still in the SE hooked up. The body on the car I'm working on now was just in much better condition or I'd be restoring the SE

 

[furryfrog]

Did put a big block in a 74' 318 car with long tube headers, tight fit, headers had some dents when done. Headers had to be on the motor before putting it in. What a chore. All that to get 200hp out of a motorhome 440. I would recomend shorter headers of somesort in the swap, something you can change the starter without pulling the engine out. My friend owned the car then and we made our own engine mounts. I have read here that you can buy conversion engine mounts to put a big block in a SB K member.

One thing to add, if you plan on using a front sway bar, see if you have mounts for it on your k member, mine did not so I had to weld some in. Not a big deal, but throw that in your decision mix pile.

Your 73 may have the iso-rubber-bushing thing going on for your rear leaf spring to axel mounting. If so the "new" rear axel spring perches will not just sit on and bolt up. Minor fabing to get it to work out though. In your case you may just be able to drill the spring perch hole out bigger to fit the bigger pin on your leaf spring.

- - - Updated - - -

 

[YY1]

Yes, you can weld a thick washer or two in the rear shock plate if you'll be using an earlier axle housing, that will help eliminate the ISO rubber pads and associated brackets.

My Satellite also did not have sway bar brackets. I think RL and WL cars with /6 or 318 might have been likely not to have a front bar.

If it were me, I'd yank the complete K from the BB car, rebuild it (including poly or solid K to frame bushings), and then transfer it over.

 

[Bruzilla]

I'm doing this swap right now, just into a 74. I'm using the Schumacher mounts. I'm using Hedman 78070 headers, which are shorter and tighter fitting than long tubes, but also require the use of a mini-starter.

The only issue I've encountered so far is the water pump housing. 73+ engines have the water opening on the passenger side, 72 and older engines go to the driver's side. You should upgrade your radiator anyway, but make sure you get one that matches the pump housing.

 

[vetteman91]

I did this to my 74 RR using a '68 383 engine using the Schumacher mounts. I also installed Hedman headers(#78036 if memory serves me right). I did not cut out pass fender and installed headers by tilting engine slightly to drivers side to slide header in from bottom. Worked fine. Only dent in header was on driver's side to clear end of mini starter. I ordered a new waterpump/ aluminum water pump housing from 440 Source( they have these to exit either side of engine) . Since I was buying a new aluminum radiator anyway I went with drivers side outlet and used 3 Row Champion radiator (#CC375). I am also going with twin electric cooling fans. Using the SB k member is no big deal. As suggested before I would make sure to upgrades the torsion bars.

 

[YY1]

IIRC water pump outlet orientation also has to do with whether or not the car and/or engine were equipped with A/C.

This can also affect pulley depth on the center line of the crank/alt/ps pump, and possibly put you into what I affectionately like to call- "pulley HELL".

 

[Steven73SE]

Ok so as far as the rear axle housing and leaf springs go, I didn't get a "new" rear, all 4 of the cars I have had 8 3/4 in them when I bought them. The one for this car is out of it right now, the the entire rear is still assembled. Leafs rear axle housing, drums, tires, it's all still one asswmbly so shouldn't be any issue there. I'm looking at getting the Schumacher mounts and their tri y headers. Anyone ever used these headers

 

[Nacho-RT74]

IIRC water pump outlet orientation also has to do with whether or not the car and/or engine were equipped with A/C.

This can also affect pulley depth on the center line of the crank/alt/ps pump, and possibly put you into what I affectionately like to call- "pulley HELL".

no, water pump housing is just about year production... changed from 73... A/C or not, pump housing is the same. Then radiator was matched to this new setup.


on 72 and earliers the pump housing with outlet on driver side also made to install the steering pump higher on engine bay, totally attached to water pump housing itselt, on top provisions

with the new outlet location on 73 and lates models, the steering pump could be installed lower into engine bay. Blocks got a provision to held the steering pump attached to, at the same time than a bracket on water pump housing.

This change PROBABLY was made ( just my thought ) due the Air pump installed on big bodies for emission controls just right at same location of earliers steering pumps, which I think began on 72/73 period

 

[Steven73SE]

Also if I'm looking at the correct part, it already has a sway bar on the front K member I believe. If it doesn't have the bar attached I'm fairly certain it has the mounts

 

[Steven73SE]

Ok guys after more research and looking at the pics posted earlier and inspecting my own k member I've come to the conclusion that one of the previous owners had already converted this car to a big block. It already has the front sway bar mounts welded in, and after reading the instructions for the Schumacher mounts, the motor mount has already been drilled and shaved down previously