I have a Canadian 2f with the flat top pistons that I am rebuilding for my 1977 FJ45. I know it is original block and head with the flat top pistons, as are the other two 2f's I have. I also know that the US models may have had dome top pistons for those years. My engine needed boring so I ordered new pistons and the ones the supplier got for me (ITM ENGINE PRODUCTS) are domed, not flat like original. Apparently these are the only ones listed for the 2F. Can any of the engine gurus out there tell me if I will have head/valve clearance issues if I use them??