170ci gasket bore size

kenny170

Well-known member
Does anyone know the bore size of a 170ci aftermarket head gasket? I'm trying to calculate compression ratios with David and Dennis compression calculator,but I can't find the bore size of the head gasket. are they all the same? Do you order the gasket to match your overbore?
 
Thanks, that's where I was getting confused I thought they would be different. then according to the performance hand book it will be a 3.81bore.
That's what I needed to know.

Thanks Kenny.
 
Thickness of available aftermarket composite head gaskets range from about .050 to .060. You would need to find a NOS steel .025 or have someone make a custom one out coper if you wanted thinner then a composite.
 
bubba22349":3g3l6g82 said:
Thickness of available aftermarket composite head gaskets range from about .050 to .060. You would need to find a NOS steel .025 or have someone make a custom one out coper if you wanted it thinner then a composite.

I have a couple of the NOS steel 0.025 head gaskets for the 144-170 engine, Ford # C0DE-6051-C, if you're interested.
 
kenny170":27k8eyqg said:
Does anyone know the bore size of a 170ci aftermarket head gasket? I'm trying to calculate compression ratios with David and Dennis compression calculator,but I can't find the bore size of the head gasket. are they all the same? Do you order the gasket the match your overbore?


No, not all the same. Ford used a stock bore for 144, 170 is 3.5". The gasket is about 3.5625" in diameter. It allows for a 60 thou over bore before ledging. Its probably around in stock , approx 22 thou thick gasket depth if you can find a source of new old stock parts.

You can certainly use a 3.3 gasket if you are stuck. The annular difference is 3.740" verses about 3.5625, only 88 thou extra each side.

The small bore engines can be played around with quite a lot, you can easily take a 170 out another 17 cubes at least with a small 60 thou or so over bore and the longer stroke four bearing 1963 to 1964 3.126 stroke 200 crank and rods verses 2.94 inch stroke crank. There is a common Chev 1977-1980 200 V6/1978-1979 267 Chev V8 piston which can fit to a reamed out stock forged 4.715" tall 3.3 con rod.

The Argentinians used a 187 cubic inch engine, with a 62.5 thou over bored 170 block with a four bearing 200 crank, a direct bolt in, but still the same 144 / 170 gasket.
 
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.
 
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.
 
Seven bearing 170's were made as a special batch for North American Falcon and Futuras with 6015 Special cast on the block in 1962. They were then used in Australian Falcon sixes from mid 1964 on wards. The 200 remained four bearing in Fairlanes from 1963 till mid 1964, then went seven bearings.

The Maverick apparently had a seven bearing 170, but I don't know if it was from 1969 or from 1972. There was some conflicting info from Consumer Guide in 1972, that indicated the 170 and 200's in Mavericks were still four bearing till 1971.
 
Currently almost all vendors list Falcon Six head gaskets as fitting 144/170/200 and 250 although it isn't correct as mentioned.

Unmolested '71 Maverick 170 I have is 4 main bearing C9xx block with uncommon D0xx head but no mythical 7 mains...

have fun
 
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