OK, this is interesting. Chrysler part numbers.
1978
#1 bearing 3832601
#2 bearing 1821772
#3 bearing 2121726
#4 bearing 2121727

1979, 1980, and 1981
#1 bearing 4100754
#2 bearing 4100755
#3 bearing 4100756
#4 bearing 2121727

Notice number 1, 2, 3, changed in 1979 before the hydraulic cams, While the #4 bearing (the one, every one was concerned about) never changed.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Thanks Charlie! I stand corrected.

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Casually looking for a Clifford hyperpak intake for cheap.

This puzzle isn't going to be conclusively solved just based on parts catalogues. Keep in mind that Chrysler part numbers often change despite there being no fit or function change to the part. Examples abound; a 2098 300 voltage regulator is identical in every respect to a 3000 074. A 2875 560 starter is identical in every respect to a 3656 650.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

But there is no part number change, except for the front three bearings, between 1978, and 1979, and the bearings did change. The only difference I can see between the "early" bearings and the "late" bearings, is the #1,2,3 late bearings are shorter. I am thinking there might have been metal taken out of the block, in that area.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Aaaaah, okeh, gotchya. I must not have read carefully enough.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Not that anyone would care but i have been running a hydraulic set up in my Dragster which is a 1962 block for several years now. Works fine. Current grind is .545 lift 241/246 @ 050" hydraulic . Pulls to about 6300. (my shift point. ) before this I had a street cam, hyd as well .430 lift @ 224
Don

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Don

@ Dolmetsch, got a question for you- where did you get your hyd. lifters?
The last street slant I put together ran a pretty stiff Hughes cam (about .510" lift, aggressive lift but short duration- springs were about 280-300lbs over the nose). It ran great, except if it sat more than a day, one or two lifters would bleed down, & once you had lots of clearance, it was difficult to get them to pump up again. At the time my source was Napa parts -not high quality & those lifters had to have been on the shelf for 10+yrs. (Chrysler dealer said- obsolete, look somewhere else.)

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63 Valiant Wagon
225 - 4 bbl

Look on e-bay for the hydro lifters. I see them quite often, and not very expensive.
Here you go e-bay number 260389162626

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225