K-Frames

[DBZ Charger]

I'm needing some clarification. I've read on many different sites many different things & I'm hoping to get straight answer here. I have a 73 charger with original 318 in it. Is there a difference between small & big block k-frames in 73? I know they changed the type of motor mounts in 73 to spool & that they make mounts to put a big block in a small block k-frame. But are there 2 distinct K-frames for big & small blocks in 73? Thanks

[JB400]

You have heard correct. 2 different k members for 73 onward

[DBZ Charger]

Any chance you know how to identify them or got a part # ?

[Nacho-RT74]

pics side by side

[Kern Dog]

It looks like the big block mounts are just a little further forward.

[birdsandbees]

It looks like the big block mounts are just a little further forward aft.

There.. fixed it for you! 

[Alaskan_TA]

Shaped different too, easy visual identifier from the side view.

[Alaskan_TA]

A link to conversion mounts, says they are out of stock right now though;

http://www.engine-swaps.com/Pages/ProductsYear/73UP.html#head2

[400sforever]

You shouldn't need any conversion mounts unless you are referring to big block motor mounts. I pulled the factory 318 out of my 74 and put a 512 right in. I just put factory big block motor mounts on the 512 of course and in it went. .but maybe there are other issues that some may have that I never came across?

[Mike DC]

   
IIRC the passenger side inner fender sheetmetal was slightly different on the BB cars too.  Servicing clearance.   

[Nacho-RT74]

You shouldn't need any conversion mounts unless you are referring to big block motor mounts. I pulled the factory 318 out of my 74 and put a 512 right in. I just put factory big block motor mounts on the 512 of course and in it went. .but maybe there are other issues that some may have that I never came across?

they are diff that's a fact.

now, you can fit a BB into a SB K members and backwards. Yes, has being done many times. Down here everybody changes the 400 it came all 73/74 Chargers with a 318 because the lack of parts available for BBs. Is correct? no, you can get driveline aligment and tranny linkage issues, premature mounts fails.

is not just the engine mounts position on K member, but the paralellism between them. You can see how the SB K member gets driver side mount more to front than passenger side. BBs are lined up.

[DBZ Charger]

There is not much difference between the two but you can see it side by side that's for sure. I had purchased a BB k frame but didn't know for sure it was one till I saw the side by side pics. I'm hoping to go BB with a stroked motor so I would like it sitting in there like it's supposed to. Thanks for all the help...I'm sure I'll have more questions to come as I work my project

[Nacho-RT74]

As mentioned, there is also an opening on passenger side fender on BB cars covered with a rubber matt, which is larger than the SB cars with a metalllic shield, like driver side, BUT this won't disturb on anything. Has being told is for easier spark plug replacement. I can't tell that is actually truth.

[Kern Dog]

It looks like the big block mounts are just a little further forward aft.

There.. fixed it for you! 

Thank you. For some reason, I just assumed the picture would have shown the LA series version first, at the left.