D19 vs. P18 Engine. what's the Difference ?

[GTfastbacker]

Today I took a closer Look at the Engine Number of my 41 D19 Business Coupe.

 

I was surprised to see a P18 stamped into the Block.

 

What's the technical difference between these two engines?

 

Thank you

Joe

Edited June 20, 2024 by GTfastbacker

[Bob Riding]

6 HP. Same displacement. Plymouth wins! Chrysler's Flathead engines

[GTfastbacker]

1 hour ago, Bob Riding said:

6 HP. Same displacement. Plymouth wins! Chrysler's Flathead engines

 

these are good news. Thank you !!!

Edited June 20, 2024 by GTfastbacker

[SteveR]

The P18 was installed originally in a 1949 Plymouth car. 217.8 Cu in 97 hp

the D19 was originally in a 1941 Dodge The engines were the same displacement but the dodge was 6hp less

As Bob says Plymouth wins!

[Bob Riding]

6 minutes ago, SteveR said:

The P18 was installed originally in a 1949 Plymouth car. 217.8 Cu in 97 hp

the D19 was originally in a 1941 Dodge The engines were the same displacement but the dodge was 6hp less

As Bob says Plymouth wins!

As it should!

[Sniper]

So, what is the difference that makes that added 6 hp?

[Doug&Deb]

Higher compression mostly. Possibly some changes to the timing also. Improvement was made incrementally until the end of production of these engines.

[GTfastbacker]

so how can i be sure it’s the whole P18 engine and not only the P18 block with the D19 attachments?

There is no car arround to compare.

[Doug&Deb]

Unfortunately you can’t unless you dyno the car and find out the horsepower. I have the same situation. The engine I rebuilt for my 52 Coronet came out of a 51 Coronet but decoding the numbers revealed it to be a 58 truck engine. It had all the correct ancillary components from the car so only the short block is the 58 engine. I feel a slight improvement from the original engine but that could be my imagination.

[Bob Riding]

3 minutes ago, GTfastbacker said:

so how can i be sure it’s the whole P18 engine and not only the P18 block with the D19 attachments?

There is no car arround to compare.

the block is stamped P18****. The head may or may not be Plymouth. Engines were commonly replaced with newer models. I would check your engine against pictures of "41 Dodges and '49 Plymouths. Many items probably were used by both makes. 

[greg g]

23 hours ago, Doug&Deb said:

Higher compression mostly. Possibly some changes to the timing also. Improvement was made incrementally until the end of production of these engines.

D19 was 6.5 to 1, p18 was 7.0 to 1.

[greg g]

Accessories should swap easily .  The distributer in the Plymouth would have a bit more aggressive timing curve in response to the thunderous increase in compression.