Technical For The Early Hemi Experts

I’m currently doing a 241 baby Hemi. One of the challenges to getting some power out of this motor is to raise the CR. I know the stock CR is around 7 to 7.5. I’d like to get it to upwards of 9 to 1. Question I have is will a 315 head work on the 241 block? The 241 I have is already .040 over so .060 is the next step.

 

Personally I'd go for a minimum overbore and 10 or 9:1 pistons, but with sonic check .125 may be possible. Yes you can use any Dodge head on your block. The advertised C/R on a 241 is 7.0/7.1:1. One measured out at an actual 6.19:1. The 315 has a wider bore therefore a bigger combustion chamber, would drop C/R a bit, but has bigger valves & ports.

 

If you want to raise compression that much,,,,you will need custom pistons .
You can’t mill the heads or deck the block enough to fix this .
Hot heads can sell you a set,,,,,about 900 bucks or so .
But they are top of the line pistons,,,,Ross .
The higher compression really wakes these little motors up though,,,,then they really run like a Hemi !

Tommy

 

It may have had the compression raised at the time at the time
of the over bore?

 

A heads up -
That would be (from the words in red above) "larger" bore.
There is no such thing as "wide" when talking diameters..! That would be larger "diameter" Go ask ANY math teacher.

Mike

 

Was a bit pressed for time when I typed it up.

 

He didn't say if it had flattops or not.

 

Check with Gary, "73RR" here on the board, he's Quality Engineered Components, on prices on pistons.