is there anyway u could use 3.8 pistons in a 3400?

[no_doz]

im just curious-i was looking around & noticed that the 3.8 has a lot more aftermarket parts available for it than our motors-i also noticed that the bore is only .18 bigger-so my question is-is there enough room in the block to pop the old cylinder sleeves out & put 3.8 ones in (if they were cut down a bit-because i noticed the stroke is .09 more on the 3.-what do you guys think?

[SappySE107]

Sure, anything is possible. Once you pop those cylinder sleeves out, you can put any others in there you like.

[IsaacHayes]

lol @ the sleeves.

[34blazer]

only .180 larger bore on the 3.8

[no_doz]

without the sarcasm-seriously is there enough room? also what is the diameter of the wrist pins so if the sleeve thing actually is feesible-gotta see if the 3400 rods can accept em-& also does anyone happen to know how tall the pistons are for both? if the 3.8 is too tall to work then thats out. also about the sleeves-i know on a lot of small motors you can remove the sleeve & bore out the block itself & then install a larger sleeve (its what they do with a lot of atv big bore kits)-being a chevy im just curious as to if the block has enough space for that or if id be tearing into the waterjackets or anything else. im very serious about this question-its just a question-if its feesible please let me know why or why not. thanks

[SappySE107]

I have a better idea if you want to use 3.8 pistons. Swap in a 3800. Its much cheaper and easier.

[IsaacHayes]

.18 over bore is waaaaaaay to much... Go 3900

[no_doz]

whether or not i actually want to do it-my point behind this whole question is-is there space in the block for the larger sleeves?

[Superdave]

whether or not i actually want to do it-my point behind this whole question is-is there space in the block for the larger sleeves?

No, there is not.


the 3500 LX9 has big enough bores to accept a 305 SBC piston with a .030" overbore. (3.73") FYI

[SappySE107]

whether or not i actually want to do it-my point behind this whole question is-is there space in the block for the larger sleeves?

Yes there is room in the block for larger sleeves. I already told you that.

[no_doz]

i thought that was sarcasm-my apologies-thanks man

[no_doz]

im just toying around with unique 660 ideas for the future-& besides the displacement being less (with the 3400 stroke and 3.8 pistons the displacement comes out to 3.7l)-if a 2.8 crank were to be used in conjunction-could the crank handle it (if higher compression pistons were used and a more aggressive cam)-and although the displacement would be the same-wouldnt the shorter stroke (if used with a light flywheel) allow the engine to spin up a lot faster without losing much power (if any) due to the size decrease only being about 50 cubes? also would the difference in stroke require the ignition timing or cam timing/actual cam used-to need changed? (i fully realize that what i am talking about is a lot of work & would be on the costly side-but im just looking into the things i could do in the future so i can see what things i need to look out for)- i figure if the displacement were kept the same but the stroke shortened-then the engine would rev quicker while not effective gas mileage during normal driving conditions-what do you guys think?

[IsaacHayes]

There are no sleeves in the iron block. It may be possible to sleeve it I don't know though.

And why would this benefit you any? Just cause you go with a 3800 piston, what will that accomplish? You can't use any other 3800 performance parts on there.. They are 90* block and we have 60*.... Can't swap heads,.... so what's the point other than increase in displacement?

It's going to cost a lot to make a big bore short stroke motor, but one of those would like high compression better as shorter stroke has less tendency to ping. You could do a 3400 with a 2.8 crank and custom high compression pistons/rods, and 3500 LX9 top end.. That would rev fast and flow like mad. It would be 3.0-3.1L so that's good on mileage, and would be very efficient with the high compression and 3500 top end. Of course a decent cam would up the power even more. Just don't go too radical on that as that can lower vacuum and hurt mileage as well. But a decent cam can bump power and bring up MPG.

[SappySE107]

Right, its not actually sleeves but I have already looked into sleeving the block for a 3.8+ bore size. Its possible, and it would offer something unique. Now that the 3900 exists (and more importantly, the 3500 VVT, its a waste of time to me. Its very expensive to sleeve a block.

[RedBird]

There are no sleeves in the iron block. It may be possible to sleeve it I don't know though.

And why would this benefit you any? Just cause you go with a 3800 piston, what will that accomplish? You can't use any other 3800 performance parts on there.. They are 90* block and we have 60*.... Can't swap heads,.... so what's the point other than increase in displacement?

It's going to cost a lot to make a big bore short stroke motor, but one of those would like high compression better as shorter stroke has less tendency to ping. You could do a 3400 with a 2.8 crank and custom high compression pistons/rods, and 3500 LX9 top end.. That would rev fast and flow like mad. It would be 3.0-3.1L so that's good on mileage, and would be very efficient with the high compression and 3500 top end. Of course a decent cam would up the power even more. Just don't go too radical on that as that can lower vacuum and hurt mileage as well. But a decent cam can bump power and bring up MPG.

he wants to see about 3.8 pistons because they have a bunch of forged options.....