motor mount change 318 to 400. 71 D100

[Blizzard523kf]

Hello, thanks in advance for any help...changing out 318 to 400, the motor mount pad seems the same but motor mount itself has 2 holes instead of central open line for single bolt ?? am I missing an adaptor or just dumb? (pics attached)

thx, Karl

[dodgeboykim]

Do the 2 rubber mount bolts fit into the 2 frame holes. Thats where they go.

[Blizzard523kf]

they do but that leaves me with a single center bolt and the motor mount that goes on the engine has 2 separate holes, that's what has me puzzled. I might just cut a center opening from hole to hole

[BigBlockTrucks]

Hello, thanks in advance for any help...changing out 318 to 400, the motor mount pad seems the same but motor mount itself has 2 holes instead of central open line for single bolt ?? am I missing an adaptor or just dumb? (pics attached)

thx, Karl

That looks just like the pair I have on my 440. They are motor home brackets.
Check with 440 source. They sell the big block brackets for sweptline trucks.

[PwrWgnDrvr]

Hello, thanks in advance for any help...changing out 318 to 400, the motor mount pad seems the same but motor mount itself has 2 holes instead of central open line for single bolt ?? am I missing an adaptor or just dumb? (pics attached)
thx, Karl

I have a set available off a 68 with 383.

[Wildergarten]

Hello, thanks in advance for any help...changing out 318 to 400, the motor mount pad seems the same but motor mount itself has 2 holes instead of central open line for single bolt ?? am I missing an adaptor or just dumb? (pics attached)

Not to cause you pain, but the three-point motor mount system in '69-71 was (to my mind) far inferior to the manual transmission mounting system which preceded it (the A727B auto trans mounting system was always 3-point). I used to rip out front engine mounts on my old Dart entirely similar to yours with only a 318. The '68 and earlier mounts were four point, with two huge mounts on the bell housing, which is a great place to take up the torque. Unfortuntely for you, the crossmember design was changed in '69, making intalling superior mounts problematic. So if you are planning to make a 4bbl fire-breathing monster out of that motor, you might want to look into your options or at least install torque limiters to protect those new mounts. I've seen them made of both cable and chain.

[Blizzard523kf]

thank you all very much for the help...think I will modify them a bit to fit...motor is not a fire breather but will snort some...will strap it down as well.

[BigBlockTrucks]

I am curious to see how this works out. I was told you only have to cut the hole for the one bolt side of the mount. I can’t attest to this because I haven’t done it yet.
When I get it mocked up in the truck I will know more.
If all else fails I will get the brackets from 440 source.

[Blizzard523kf]

worked out pretty good with a little modification...now for the headers