300hp magnum crate 360 convert to 380hp?

[JeepJimmy]

has anyone converted the magnum 300hp 360 MP crate motor to the 380 hp model. from what i can find its only the cam and to a single plane intake. any ideas??

 

[POS Dakota]

I think the 380 came with the r/t head casting also. No?

 

[JeepJimmy]

no. thats the 390hp newer crate motor. heads are the same on the 300 and 380 from what i can find.

 

[bigdemo1]

the magnum crate never came 380 did it?

 

[dgc333]

The magnum crate engines came as 300 HP or 380 HP until they stopped making stock magnum heads. They then switched over to the magnum R/T head and the ratings were 320 HP or 390 HP. In anycase all the 380 or 390 HP motors dyno'd at over 400 HP when tested.

I have heard conflicting stories as to where the pistons were different in the 380/390 HP engines compared to the 300/320 HP engines.

You can certainly swap the cam and intake and get a good bump in HP and if the pistons are the same then you would have the 380 HP motor.

 

[JeepJimmy]

i found an old MP catalog. it shows the P5249464 valve spring for both motors. so im guessing that it should be fine...

 

[Guitar Jones]

Yes, just the cam and intake swap will do. That's why Locomotion runs the 300 horse crate in his CM class IHRA stocker because you are allowed to change the cam and intake. Presto, instant 380 horse engine on a 300 horse index.