kenny170":2782159e said:
Rock auto has head gaskets in Victor, Felpro and sealed power for 144 and 170 but they don't clarify the bore size. I thought it wasn't a good idea to take these engines out to 60 thou over the walls get too thin.
The Cleveland engine plant made these engines, but after 1969, they introduced the Small Block Windsor/Cleveland process of egg thin bore castings. It was not the 144/170 that used the first thinwall process, but the landmark small block Windsor Ontario cast 221 Fairlane V8 engine in 1962.
After seven years, they racked down the cylinder wall thicknesses to just 130 thou in the new 351 Cleveland from that engine plant. Ford never changed or improved the thin wall process untill 1985, after years of service problems with 302 and 351 Windsor engines. After rust, a 130 thou thrust face thinckness could become 90 thou in service. To run 11:1 compression normally aspirted to 7000 rpm on a short stroke engine with a rod ratio of less than 1.7:1, you need around 180 thou thick bores at the thrust faces for safety.
As far as I can tell from the early information, in the early 60's, before 1969 when FoMoCo rolled out even thinnner thin wall castings, all the small and big I6 and V8 blocks were really quite thick, with early 144's being easily able to be bored out to 1/8" to 155 cubic inches. So that's 3.625" on any old 144/170 block. The seven bearing 3.68" bore 200 and 250 and 3.5" bore 170 engines were from then on made with thinner wall castings, although some 250's are able to risk fitting 70 thou over 258 Jeep pistons without breaking blocks. Like
powerband, for instance. I've used 229/305 Chev pistons at 3.736", or 56 thou over, on 250 Aussie engine blocks with ease.
On an early four bearing 170, you are certainly safe with a 60 thou over bore, and perhaps even 125 thou if it passes the sonar ray test, doesn't have too much rust or core shift. Check the lifter casting centres, if it looks like there is core shift, don't over bore it more than 60 thou.
