woah i thought wiseco only made atv and motor cycle pistons??

The important thing to look for in a replacement cast aluminum piston is if they have cast-in steel expansion struts.

Look closely at the inside of your factory pistons , around the pin bores and you will see steel plates that are now part of the casting... those make the piston stronger and more stable.

There are other features to look for, like ribbing along the inner edges of the skirts and over-all skirt thickness, so try to get a sample piston to review prior to purchasing a set.
DD

after 3 weeks ,the new kb pistons i ordered from summit are in ,but are not going in my engine. the piston with rod is 10 year old kb with 500 miles on it. it has strut plate,oil holes and ribbing support above oil ring groove and still looks like new. the new pistons have no pin oiling whatsoever and in the pics no ribbing/support above oil ring groove. an original 3.40 bore mopar piston that i use as a pen holder on my desk(i just noticed all the pen ink on piston bottom and will soak in carb cleaner) for comparison. does mark at cp pistons make factory .030 pistons and is group buy still going on? ron

i called summit and they issued a ups call tag right away. the second salesman i talked to noticed in my comments ordering section that the pistons had to be usa quality made and these are made in mexico. kb's are made here but not for this application . full shipping and money refund was issued. they want me to try federal mogal's made in the usa. anyone using those pistons? did mopar offer .030 pistons? anyone have a part number? thank you

hi ,this is the other piston set that came in . the speed pro sealed power's are also going back. no strut support plate,yellow paper shows no oil ring land support, 1/2" shorter length, and over 100 grams lighter than stock. and cast into the inside says "made in india" . more pics for comparison.

The pistons I put in look just like the bottom one in this picture and they had the steel plates in them. I weighed each one and removed material to get them all the same and drilled and countersunk oil holes in them for pin lubrication.

They seem to be ok for my usage, but I don't have many miles on my engine either.

Joe

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1964 barracuda 198 slant

I've got a 9.75:1 compression big cam slant six in my daily driver duster with a 100 shot of nitrous It scoots perfectly along with .40 over stock pistons on nitrous or off. Gets me to school and work a bit faster that way

Kev

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hi, after the speed pro's/ sealed power looked like they were cast in a sand mold and then stepped on by a camel, i had to look around. i found 12 nos pistons. the top 9 are probably 1967 or 1968 pistons. the mopar paperwork in closest piston is date coded march 1968, but was in the box of 9 pistons in rear. they are not destroked. the 12 pistons have 1.76 centerline(or 1.31 to top of piston from wrist pin, not 1.74 c line or 1.29 normally). 9 match and 3 are different plant/vendor. made in u.s.a.

Nice score... and it is always nice to have a few extras so you can "pick & choose" your way into a great set of 6.
Time to get out the gram scale and do some weighing.
DD

hi, i dug out the engine scale. all the original 3.40 bore pistons with pins and no rings are 597 to 607 grams. with rings 629 to 639 grams. the top 6 lighter grey .030 all weigh 607 to 608 with pins. the bottom .030 3 + 3 all weigh 614 to 615 with pins. i thought 3 pistons were different but they are the same, just machined different on top for weight removal. you can see above the wrist pin the fac must have machined off the aluminum to balence. the guy i bought them from bought out a mopar dealership in the 70's and said thats how they came in the 2 boxes. very glad that both sets are equal to each other plus or minus 1 gram. all the pins from old and new pistons are either 129 or 128 gram. ron