Small to big block

[06Daytona]

What's involved structurally to change a 70 Challenger from a 318 to a 440? I know the motor mounts have to change, but I'm wondering if the frame needs stiffening or boxing etc. I've decided not to grab the 440 R/T at the moment, but if I can ever get a hold of the guy with the 318 car I'm sure my wife can talk him down to 5000. I want the next car that I fix up to be either a big block or a vert and verts are few and far between down here if they're Mopar. I may end up having to go through Ebag if I can't find anything down here.

[HP2]

Structurally, nothing required, but torque boxes or sub frame connectors are suggested. Heavier torsion bars and leaf springs are nice additions too, but again, not necessarily required to make the swap. Tranmissions are family specific so your small blocks trans won't work with the big block. If you have a rear smaller than 8.75, you mihgt want an upgrade there, depending on what  you find under any car you get.

[MEK-Dangerfield]

You'll need a different radiator too.

[purple1]

Along with parts already mentioned, A/C hoses and brackets if equiped with A/C. Also depending on what transmision is in the car you may need another drive shaft. If the 318 has a 727 or a 4 speed you should be ok. But if it has a 904 you will need another shaft or will have to have the shaft shortened.

[DonP1]

I thought you would need a new K member, or is that only for a Hemi? I have a 360 in my 70 Challenger (bought that way). It was originally a slant 6.

but if I can ever get a hold of the guy with the 318 car I'm sure my wife can talk him down to 5000.

Sorry, but I have to know - please explain how she does this?

And what's a Vert?

[Skunkworks Challenger]

All v-8's except Hemi take the same k-member.  I just changed my car , originally a big block car back to big block after someone had put a 340 in it.  All the belts and hoses will be different as well as fan, spacers, brackets etc.  The exhaust pipes off your small block won't fit a bb either. You won't like changing spark-plugs in a 440. Strangely, the starters will interchange as well as flex-plates and torque converters if automatic, assuming the cranks are made from the same material.  The throttle cable very likely will have to be changes.  That's all I can think of other than what others have mentioned.  PK

[06Daytona]

Sorry, but I have to know - please explain how she does this?

And what's a Vert?

I don't speak much Spanish so my wife usually ends up telling them what we're willing to pay. She's pretty good at it too. She knows the island and what the economy is like in different areas.

I knew about all the belts, hoses etc needing to be changed. I was thinking more on the structural side if it was going to be a huge pain welding in braces and stiffeners and stuff.


Vert, convertible.

[AARuFAST]

Structurally, nothing required, but torque boxes or sub frame connectors are suggested. Heavier torsion bars and leaf springs are nice additions too, but again, not necessarily required to make the swap. Tranmissions are family specific so your small blocks trans won't work with the big block. If you have a rear smaller than 8.75, you mihgt want an upgrade there, depending on what  you find under any car you get.

   Torsion bars should be changed. Purchase a new flex plate. Don't need to change K frame.
Cut the top from a HT to make a vert. u won't find any in P R.   

[dodj]

Did you cut that car to make it a vert AARuFast?

[Matt70]

If going with a 440 six pack do the fuel lines and sender need upsized to 3/8's?   Matt

[06Daytona]

I would think they would need to be upsized. Even if they didn't I usually change fuel and brake lines when I buy a project car, unless they're visibly new.

[MEK-Dangerfield]

If going with a 440 six pack do the fuel lines and sender need upsized to 3/8's?   Matt

I'm still running 5/16 lines on mine. I have had no problems. Of course, I don't spend time at the drag strip either.

[Cooter]

As a standard Practice, I ALWAYS upgrade ot the larger 3/8" fuel line as I know I dumped that 440 in there and wasn't planning on babying it...

[Topcat]

the starters will interchange as well

While they will interchange, the HP Big Block starters had more windings of the electric motor than the small blocks did.

[Matt70]

What about the wiring harness? I would imagine they are different.