Ok say that for some reason you wanted to do a n/a build with a 4.2 block if you bored it over would you get more power out of it?? I am asking because i got a 98 4.2 motor that has bad rings in it. How far can they be bored over before problems happen.I know that 302can go 60 over. but i throw them away at 40 over.

I wanna try it and see what happends plus it get rid of my blown up 3.8 motor too because i can pull the get parts off and junk the rest of it.

If i do build it there will be no power adders (nos,s/c,turbos)just stright up motor.i want to make the most hp that motor can put out

 

i dont know for sure, but i believe people usually stop at 30 making 4.3

 

i believe 60 over was tried and it caused problems

 

yea i was thinking 60 over way to much. wat if it was sleaved? then 60 over not might be bad.

4.2 +.60=4.8 nah to much
4.2 +.40=4.6 <---- hehe a v8 displacement

 

No no no. That is so wrong. If you machined .6" or even .4" out of the cylinder walls then there would be nothing left. With my .030" bore I have .31" of cylinder wall left between them(yes I did just measure that lol).
4.2L + .030" bore = 4.265L = rounded up to 4.3L
To make it a True 4.3L you will need a .050" or .060" bore.
The bore is in hundredths of inches(.0X0"), not in tenths.
There is no possible way to make it bigger than a 4.3L with only boring and a 4.2L crank.

 

Never go more than 30 over with the sixer. ANd if you are going N/A, you'll want higher compression as well, so make sure you account for that when chosing pistons.

 

ok so does anyone know about how much hoper poer can be made out of a N/a build.Because i did like a lot of ppl and went fi. but my camaro is stright motor and hauls @$$.

could you break the 285hp mark on a n/a build? I am thinking it might just be a lost of money if it didnt get close to 300.

 

the safest is keeping the 4.2. any more and you'll gett some serious problems with the cylinder walls being too thin. i might be wrong,but i heard you can get about 50 more rwhp from the stock 3.8 bored to a 4.2 done with all the right things.

 

is that all? what does that put it at and does anyone know were to get a hold of high comp. pistons? and rods out of a 351w right?

what about haveing the crank polished?
I am thinking about self porting because it is cheaper.
I need a round about hp rating to see if it is even a good idea

 

Polishing the crank will do nothing.

N/A you can maybe see 265 or 270 hp at the wheels with a VERY good ground up build. (This means not self ported parts.)

My 4.2L in N/A trim made 247 rwhp...but it was low compression, and awaiting the blower set up. Higher compression and a better N/A cam would have done wonders for it.