What can you tell me about these pistons?

[lauras70mach1]

351W pistons, I think they're cast pistons. Inside the skirt it reads "220" and "RV DUTY" It's an older rebuild and I'm thinking they're just cheap replacement pistons.

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[D.Hearne]

Just your average run of the mill, standard, cast 351W truck piston.

 

[lauras70mach1]

Just your average run of the mill, standard, cast 351W truck piston.

What are the differences between truck pistons and car pistons?

 

[D.Hearne]

The dish in the middle and the lack of valve reliefs. The 69-72 (possibly later too till the late 70's) car pistons had a round dish (excepting the 69 351W 4 bbl pistons) with 4 eyebrow reliefs

 

[lauras70mach1]

The dish in the middle and the lack of valve reliefs. The 69-72 (possibly later too till the late 70's) car pistons had a round dish (excepting the 69 351W 4 bbl pistons) with 4 eyebrow reliefs

This is a '69 351W four barrel.

 

[D.Hearne]

Then you've got the wrong pistons, for sure. Unless you wanted to lower the compression ratio to start with. That application had a 10.5 to 1 ratio with the correct pistons. This site is usefull in researching pistons http://kb-silvolite.com/index2.php In looking up the Silvolite pistons for a 69 351W, you'll see theirs has 4 reliefs with no dish. It's listed as a 69-71 piston. I have both a 71 and a 72 stock piston and both have a round dish, the 72 dish being a good bit deeper than the 71's. The ratio went from 9.5 to 1 in 71, (if I recall correctly) to 8 to 1 in 72.

 

[bnickel]

D, actually i'm [pretty sure all 351w dish pistons look just like those. some have a deeper dish like these and some have a shallower dish and the early ones have valve reliefs too but for the most part they all look like these.

i've seem some aftermarket ones that have the round dish but they were super cheapo generic ones.

these look almost identical to the factory pistons in the 73 block that i have in the stang except for the lack of valve reliefs. even factory 69 pistons look pretty much like these except for a slightly shallower dish and the valve reliefs. and late 80's and 90's truck pistons look like these too. the only ones i'm not absolutely sure of would be late 70's/early 80's model pistons.

 

[D.Hearne]

I'll have to take pics of the 71 &72 pistons I have and put em up in my photobucket site. These were for dead certain, originals from the factory. I pulled em myself from the motors.

 

[bnickel]

I'll have to take pics of the 71 &72 pistons I have and put em up in my photobucket site. These were for dead certain, originals from the factory. I pulled em myself from the motors.

hmm, i wonder if maybe they were factory replacement or warranty blocks or something like that. i don't doubt you D, it's just that ive never seen any like that, every 351w dish piston i've ever seen looked exactly like these. then again 71-72 351w's had higher compression than the 73 and later 351w's but lower than 69-70 351w's so maybe it's only those 2 years. i know the Ford replacement pistons look just like these. let me do some checking and see if i can find some specs on the 71-72 pistons.

 

[lauras70mach1]

All I know is the engine's been rebuilt, but it's an older rebuild. It ran 12s in a tube chassis car with a Holley 700DP and C6.

 

[D.Hearne]

Ok, I got the pics of the 71 & 72 351W pistons up here : http://s125.photobucket.com/albums/p53/baddad457. The 71 motor was given to me so I don't know the application it was from but the date codes were all from 1971 (heads, intake & block). The 72 motor came from a 72 LTD.