BobT-47P15 Posted November 2, 2006 Report Share Posted November 2, 2006 I presume that the letter D cast into the head stands for Dodge. Looked at a spare head....it has a P there. Numbers below that D are 1311804-2...anyone know what they indicate? Presumably a Dodge part number. Click on thumbnail to enlarge. Which brings me to the next question. Is there much if any difference between a Dodge and Plymouth head. This head is on a 57 Plymouth engine. Quote Link to comment Share on other sites More sharing options...
greg g Posted November 2, 2006 Report Share Posted November 2, 2006 Shouldn't be any mechanical or fitment issue. Only difference might be that the later the engine, the higher compression ratio and incidently the HP as well. Check the Specs page on the Carnut site. For example, the 1950 Dodge 230 has a CR of 7 to 1 and puts out 103 HP In 59 the CR was 8 to 1 and the HP went to 135. Plymouth in 1954 (first year of the 230) the CR was 7.25 to 1 HP was 110, by 59 the CR was 8.0 to 1 and the HP was 132. Wonder where the Dodge got 3 more HP in 59????? Quote Link to comment Share on other sites More sharing options...
greg g Posted November 3, 2006 Report Share Posted November 3, 2006 So how come my 95 HP P15 engine with 1 carb got 16MPG, and my 56 P28 engine with 2 carbs and about 140 HP gets closer to 19 MPG??? Maybe younger horses eat less....... Quote Link to comment Share on other sites More sharing options...
BobT-47P15 Posted November 3, 2006 Author Report Share Posted November 3, 2006 I guess my point was: does anyone know why the Dodge head on the newer Plymouth motor would not work OK. When I bought the motor, the seller had a finned head and 2 carbs....which he was not going to let me have. So he sent the motor with a stock type head. My mechanic said it didn't look so great, asked if I had any other similar heads available. Happened to have this Dodge one (don't know what year its from). He said it looked better and put it on. Runs OK, but not real zippy on takeoff. Recently got about 17 mpg. Runs smoothly. So, guess it's really not a big problem. Perhaps might do just a bit better with correct year head, but then, maybe not much. Quote Link to comment Share on other sites More sharing options...
greg g Posted November 3, 2006 Report Share Posted November 3, 2006 As long as it a a 23 inch head it will fit. Again the later the head the higher the compression ratio, so in terms of power later is better. I will take issue with Normspeeds zip equation in regards to rear end gearing. The higher the number the quicker the engine will get to high rpm in each gear. The lower the number the longer it will take to reach the same rpm, howerver the road speed wil be greater. That why drag racers concerned with only 1/4 mile acceleration like 4.10 and 4.11's and higher numeric ratios, and highway cruiser love them 3.21 and 2.73's etc. Quote Link to comment Share on other sites More sharing options...
49roadster Posted November 4, 2006 Report Share Posted November 4, 2006 I have a '49 Dodge and a '49 Plymouth. The Dodge has a "D" on the head and the Plymouth has a "P". Looks like your presumption is correct. Quote Link to comment Share on other sites More sharing options...
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