questions on a stage 1 block?

[ulose2av6]

can a stage 1 3.8" block be 4.00 bored?and if so how would one get that number ie 4.5 litre 274cu in?

 

[HighPSI]

I have seen some that could be. They had siamesed bores, etc.. Just put a 3.625 crank in it to get 274" Isn't this what Red has?

 

[ulose2av6]

ok stock block has 231cu in . how does a stage one get 274 cu in with a 3,625 crank and a 4" bore. what would it be if it was a stock bore w a 3.625crank

 

[1320n10]

stock bore with 3.625 is 246.6
4.00 bore with 3.625 is 273.3
bore x bore x stroke x 4.7124 = cid

 

[buickpower]

where does the 4.7.... come from?

 

[JDEstill]

the 4.7xx is = pi/4 x no. of cyls, in this case 6.

3.14159 x 6 / 4 = 4.71239

 

[buickpower]

thanks

ahh i see..

 

[ulose2av6]

i have a stage 1 3.800" block basically its impossible to 4.000" bore this correct?or can it be done?

 

[750H.P.V6]

Ulose2av6,

If you have a 3.8 liter Stage I block casting # 25500012 it doesn't have siameese cylinder bores. The max overbore will be about 3.860" The block Cal spoke of earlier was a version of the 3.8 liter Stage II which was used in the Indy program.

Neal

 

[S2V6RACER]

Don't butcher up the block. If you need 4" bores, just get a 4.1 off-center block. I'll buy the 3.8 from you if you don't want it.

I agree with you on the cubes. If you do not have a cubic inch rule, run as much as you can, it cost's the same.

 

[mayosmechanic]

I would cautious in boring that block period.Have it sonic checked before you spend any money on it.I ran across several Stage 1 blocks that suffered from core shift and had thin walls.I had one that was down to .090 on the 0utside cylinder wall.These blocks may have the same casting numbers as the stage 2,but they where machined on the same production line as the stock blocks.Not trying to alarm any one just want don't want you to learn from the same shool I did....Hard Knocks.If it where me I would find a 4.1 block if you want a 4.000 bore.