Please tell me what modifications need to be done to a set of 273 engine brackets to use on a 340 in a 66 Dodge dart your help is appreciated thank you
Using 273 mounts on 340 66 Dart
- Thread starter Bigboy 68
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Can’t answer your question but would like to know myself
moparmat2000
Well-Known Member
No mods on RH one as far as I can tell. On LH one add a spacer between the rear mount and the rear mount ear to take up the gap, use a longer bolt with it.
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On the passenger side, the 273 block and original bracket had one bolt in front, two in the rear. The 340 block will have two bolts front, one rear. Solution is to weld a triangle shaped piece to the front ear of the original 273 bracket, and drill a hole for the second bolt. Here's a picture I took a couple of minutes ago of the one on my 65 Barracuda. (A little blurry, but I was lying on my back and pointing into the dark.)
Note: for several years after Chrysler changed the small block motor mount bracket design in 67, the company continued to offer two separate passenger side brackets. Eventually, they started making a bracket with two holes front and two rear, so that one bracket would work on both 273/318 and 340/360. Can't remember what year that was.
Anyway, below is what a 64-66 A body 273 bracket looks like when modified.
Note: for several years after Chrysler changed the small block motor mount bracket design in 67, the company continued to offer two separate passenger side brackets. Eventually, they started making a bracket with two holes front and two rear, so that one bracket would work on both 273/318 and 340/360. Can't remember what year that was.
Anyway, below is what a 64-66 A body 273 bracket looks like when modified.
pishta
I know I'm right....
drop motor down into 66 mounts and shim up whatever gaps there are. I dont think you even need 3 bolts on one side, 2 will work. Ran 340 in a 65 like this for a year and wasn't easy on it.
abodyjoe
Well-Known Member
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That diagram is in the Mopar Performance engine manual, and says it is correct for 64-66, but it is not - at least, it's not correct for a 64-65 (maybe the bracket changed for 66?). When I first swapped my 273 for a 340 back in the seventies, I made a piece according to the dimensions shown in figure 31-25, but it didn't even come close to fitting my 273 bracket. Once you have an actual 64-66 bracket in front of you, it's not hard to figure out what the triangle piece needs to look like, or to make it. As for the suggestion above that you can just run two bolts, I suppose you can. I figure there's a reason the factory specified three, so that's the way I went.
Gentlemen thank you very much for your time your pictures and your diagram and your wisdom this has helped me tremendously and I want to thank all who have replied
grimreaper
Cross Member
Yes, that diagram is incorrect. The triangle needs to be quite a bit larger. Base = 3.65", long side = 3.05", short side needs to be 2.15" Then weld it on and with a drill press drill a hole through the existing hole into the triangle.
Cluck norris
Active Member
When doing this swap are y’all using a v8 k member or the slant k member
In the early a bodies 64 to 66 the K members are the same for a V8 and a slant f y i
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Cluck norris
Active Member
Awesome, I’m starting down this road on a 66 valiant singet two door and have been digging for info on this and suspension upgrades
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