AMsee what it is...

[Nikkormat]

Hey Ted there are two sets of 401 Pistons and rods on Craigslist. I'll go halvsies with you. It'll cost us $25

[tedlovesjeeps71]

Hey Ted there are two sets of 401 Pistons and rods on Craigslist. I'll go halvsies with you. It'll cost us $25

Ok, I'm down. Any chance you found a crank laying around?

Noticed this while pulling the main caps tonight. Not the end of the world but my guess is someone used a steel instead of brass punch while trying to change a RMS.




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[tedlovesjeeps71]

Interesting.... Anyone know what these small holes in the lifter valley are? Are they stock or...?



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[Cheap Hobby]

The Pistons are Venolia reverse dome forged pistons for a chevy 400. Not an unusual choice for forged pistons. The small holes are for oil drain back. The 2 on the rib are to hold down the oil line feeding the fitting threaded into the hole on the left, the "oil mod". It looks like old glyptal paint was used to aid oil drain back as well.

[tedlovesjeeps71]

The Pistons are Venolia reverse dome forged pistons for a chevy 400. Not an unusual choice for forged pistons. The small holes are for oil drain back. The 2 on the rib are to hold down the oil line feeding the fitting threaded into the hole on the left, the "oil mod". It looks like old glyptal paint was used to aid oil drain back as well.

Thanks man. I was told that the pistons were good quality but knowing they were from a Chevy is interesting to know. I managed to find the last two caps for the floating pins that hold them to the rods. Since it had the oil mod done and "better" pistons, I guess it's a safe assumption that someone spent some effort rebuilding it. Wonder what caused it to fail since it had the oil mod done. I need to ask for more history on this thing.
I still haven't begun to measure anything yet. Was pretty worn out last night so all I really got done was pull the rings (what were left) off the pistons and spent a while cleaning the block some more. One more trip in the dishwasher and I can start checking bores and such.
For now... Happy Thanksgiving everybody!

[az chip]

Happy Thanksgiving to you!

[tedlovesjeeps71]

Thanks Chip.
Today I was able to pull some actual numbers on the motor. Looks like it's been bored .060 over. While all the cylinders are fairly close, they are way out of spec for the pistons. .013-.015 piston clearance is far too loose. Guess I'll ponder some pistons...


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[tedlovesjeeps71]

Thanks Chip.
Today I was able to pull some actual numbers on the motor. Looks like it's been bored .060 over. While all the cylinders are fairly close, they are way out of spec for the pistons. .013-.015 piston clearance is far too loose. Guess I'll ponder some pistons...


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[Nikkormat]

Ted, keep in mind those are aftermarket Pistons and may have been speced that loose by the manufacturer. I'd find a comparable set on summit and compare the instructions.

[tedlovesjeeps71]

Ted, keep in mind those are aftermarket Pistons and may have been speced that loose by the manufacturer. I'd find a comparable set on summit and compare the instructions.

I will have to do some research. I know the pistons are aftermarket and used but while the skirts show some wear, .015 is WAY loose. My instructor has a dedicated drag car and even his motor isn't that far. I'm not giving up, just have to do more head scratching before I can get anywhere with it.


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[tedlovesjeeps71]

So I am a lil curious. Obviously the big numbers on the side of the block say 401. The casting on the back confirms it.


This looks to be a serial number??


And does anyone know what these random letters are? My instructor said he has seen them on other motors but he had no idea what they mean.
I tried to highlight them and underlined them in green paint pen. Bs, Cs, and Ds...



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