guys i think that I have found a Mirror 105 block. I have heard it rumored that these are the Replacement block for the 428 but many were used as 390 or 391 blocks. I am 110% absolutely sure that the one I have found is currently a 391. My ? is being these blocks were designed as 428 replacement blocks shouldnt there be normal engine mounting positions that could be utilized to put this motor into a pickup "with several modifications first" or did they only use the goofy mounts involving the transmission on these blocks too?
Any info is greatly appreciated!

 

It is my understanding that the mirror 105 block was used in pickups as both 360 and 390 engines in the early '70s. It does have beefier main webs and thicker? cylinder walls? They were prolly used as 428 service blocks, but don't know for sure.

I rebuilt a mirror 105 block that is a 360 original engine in a '74 F 100.

They should have the standard side motor mount bosses.

 

The 105 blocks were offered as 360's and 390s for sure, though I have never heard that they were a replacement/service block for 428s. I am skeptical on this point. The 360 I took out of my truck was a 105. If you are going to find a 360/390 block that will bore to 428 it will likely be a 105. This does not mean, however that the 105 block WILL bore to 428. Have the block sonic checked BEFORE you have it bored to to make sure. It would suck to waste the money on the bore and ruin a good block at the same time.

-Scouder