• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

3800 Big Bore

C

CNorell145

New member
Has anyone attempted or successfully pulled off doing a .020" or .030" big bore on their 3800 engine?

If so, what was your approximate horsepower gain, and what pistons did you use?
 


I think there's been a few and it ends up being like a 4.2L or something, not really sure on the horse power or anything like that though. Just look it up on google, there used to be someone who had a kit put together for it I think, that or it was like a stroker kit or something.
 
After the time, money and gains etc wouldn't be worth it. There's others things that will do more for you and cost you less.
 


To do something crazy you could grab a vortec 4.3L, throw in a 4T80 trans and then turbo it. Might need an adapter plate for the trans. Would be different for sure.
 


Well to do the work myself, the parts and machine work would only cost $1500 or so, and I believe a turbo costs around $3000 or so? Correct me if I'm wrong.

Overall, I wouldn't mind having a turbo on there - more immediate power is always nice, rather than building up the supercharger.
 
I would have went with a 4.2 stroker but the only companies I found that offered them were in Australia and they wanted way too much for them
 
20 overbore gives you what like 2 extra cubes at most.

the stroker kits are not worth it unless you have a SI tall deck motor.

the SII already has horrible rod/stroke ratio from stock....why make things so much worse.

a tiny turbo on a bone stock 3800 will break most transaxles.
 
My motor is .020 over, made the holes round again and gave me a nice fresh cylinder wall finish. Speedpro/Sealed Power hypereutectic pistons with ceramic coating. As stated above over bore of .020 - .030 gives such a negligible difference in displacement you would never realize any measurable gains in output. A C.O.M.E 4.2L stroker kit with a completely custom rotating assembly might. However at $3k for rotating alone not including machine work, valve train, heads, assembly labor, big blower or anything and everything else needed to utilize the setup. A turbo is a much smarter option
 


You must log in or register to reply here.
Back
Top