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I have a motor mount question and was hoping someone on this forum could help. I have a 68 GTO and I'm having a 1970 YC block 455 rebuilt for it. Im not sure what motor mounts to use. I've read to use the stock 400cid mounts but that doesn't make much sense to me. I would think that the 455 mounts would be correct. Any help would be greatly appreciated-Thanks
 

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It really depends on how your block is configured as far as motor mount bolt holes. I don't have all the different configurations for all years memorized like some folks do, but if you have a way to post photos of both sides of your block, I bet we can figure it out. (Or maybe GeeTee knows off the top of his head. :D )

Bear
 

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I have a motor mount question and was hoping someone on this forum could help. I have a 68 GTO and I'm having a 1970 YC block 455 rebuilt for it. Im not sure what motor mounts to use. I've read to use the stock 400cid mounts but that doesn't make much sense to me. I would think that the 455 mounts would be correct. Any help would be greatly appreciated-Thanks
I have no experience in this swap, but I think whatever motor mount you use, you must use the matching frame brackets. no mixing 400 n 455 motor mount components.
 

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The frame mounting brackets and motor mounts are different for the 70 455 according to the parts list from Ames Performance. They have a picture that shows the difference in the mounting brackets. Recommend you get the entire kit like Rickm is suggesting. Matt
 

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All 1959-1969 blocks have 2 bolt holes for the engine mounts. Spacing is 5 1/8". On the 1970-1979 blocks there are 5 holes, the 2 earlier type, and 3 additional. The later 1970-1979 blocks will fit in the earlier chassis. The 1965-1969 blocks will not fit into the later chassis except 1971-74 Ventura, 1970-74 Lemans/GTO. The 1973-73 blocks only had 3 holes drilled, but have the five bolt bosses and can be drilled to fit.

So, should bolt right in with no problems or need for mount adapters.
 
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