i have a 225 slant six and might need to bore it out because the cylinder walls are pretty bad and am wondering if i can just change to a 4.0l piston i know the 3.9l v6 is bigger but it's to big same bore as a 318 or if the 170 or 190 is bigger only got specs on the 225 in the book i got on the ram hopefully i don't need to but in cae i do i want to know if i'm going to have to buy after market pistons

_________________
MOPAR OR NO CAR
1985 Ram
1975 Coronet
1998 Dakota

Time to do a little reading.
http://www.slantsix.org/articles/stroking/stroking.htm
The 170, 198 & 225 all have the same bore, the size difference comes from different strokes.

The 4.0 bore will be to big for a SL6 block but there are other piston options out there. You can bore a SL6 out to 3.500 (89 mm) which opens up piston selection.
DD

i do know how to build a stroker i'm just trying to avoid stroking mine can't really afford to start doing that with it was hoping to be able to just grab some pistons from a stock block that i could pick up cheap from a scrap yard or would i be better off to use the block i have out back and hope i don't have this problem with it has been sitting out back for a couple years now but it's full of oil and in one peice just hydrolic so i'd be changing that because all the parts i have are for a solid slant

_________________
MOPAR OR NO CAR
1985 Ram
1975 Coronet
1998 Dakota

could i get some stock measure ments i know the slant bore is 3.40 and the 3.9 and 318 share 3.91 the 360 has 4.00 the 400 has 4.342 and the 440 has 4.320 would like some for the 4.0l or anything bigger than the slant six hopefully i don't need to change pistonsbut i'm not sure if the cylinder walls will hone out last owner left it out side with out the head on it so they look pretty bad just trying to find some pistons that i don't need to order special ring for as well

_________________
MOPAR OR NO CAR
1985 Ram
1975 Coronet
1998 Dakota

What's the question?

_________________

how big is the bore on the 4.0l jeep motor doc says it is to big so this is just out of curiosity of how much bigger it is but i'm not planning on using the pistons in my slant any morehopefully i don't have to bore mine out

_________________
MOPAR OR NO CAR
1985 Ram
1975 Coronet
1998 Dakota

The power tech 4.0L has a bore of 3.88.

The 258/4.2L is 3.75.

The 2.5L 4 cyl is 3.876.

I think the max bore that one racer saw was .130 over so you're looking for a suitable block that will hold a max bore of 3.53 tops...

-D.Idiot

If the bores are worn and rusted the you will have to bore them out and get new pistions and rings. The maximum suggested oversize a bore can be before getting different pistons is .010 and at that amount of ware you will hear some piston noise. (slap)

If the bores have more then .007 of taper, top to bottom, the rings will have a difficult time sealing, even if the walls are smooth. If the bores have any scratches or pits, the rings will not seal, bore walls must be smooth and round.

If you dont have the money to bore and get new pistons for the rusted block, find a different block with nice bores that you can hone and re-ring.
DD

i've got two out back but they are both post 81 hydrolic cam engines so i don't really have a good replacement unless i can still put every thing in these blocks without a problem

_________________
MOPAR OR NO CAR
1985 Ram
1975 Coronet
1998 Dakota

I am fairly cretian that you can use a hydrolic block and head with a solid cam. Go for it you just get a little extra oiling. Personaly if it were me I would use a hydrolic cam(offered by comp cams).also if you use a solid cam in a hydrolic block you still need toe solid rocker shaft and rocker arms.

i'm going to get my grandpa to look at these cylinders walls he used to be a mecanic years ago still works on air planes as a hobby but he might be able to tell me if they will need to be overbored

_________________
MOPAR OR NO CAR
1985 Ram
1975 Coronet
1998 Dakota