400 HP/Police Engine

[Mopartx]

I am wanting to know what the difference is if any from a standard 400 from a 75 Highway patrol 400 engine other than the 4 bbl. carb and manifold. From researching the net, it appears that after 72, the hp of this engine was tuned down, not up. I will make an assumption (not an ass) that the 346 heads were the stock heads. And none that I know of ever came with a steel crank. So if anyone knows....please advise. I know where one is cheap, but I don't care to get the surprise after I buy them...thanx

[DartGT66]

I think they usually had a double roller timing chain, a windage tray, and moly rings in the pistons. Maybe even HP valvesprings and somewhat different cam specs.

[451boy]

HP motor and police motors are the same thing for Mopars. Maybe some police agency was a big enough customer to special order something, but I've never seen any proof of that. Typical police engine code would be E86 which is the same exact E86 that Joe Blow got when he checked the right box. Jyrki gave you a good description of the typical differences for a late 70's HP motor.
400 motors did come with steel cranks but not a lot of them were made that way. I've seen one but that is it. No big deal, if you want a steel crank just use one from a 383. Easy way to tell is if the ID pad has an E stamped on it. E means cast crank.

[Gary]

I had a 400HP from a '75 Sheriff's car. It had a cast crank, and did not have a windage tray or double roller chain. The heads were 452's. There was no obvious difference between it and a standard 400. One thing it did have was a monstrous alternator. A friend put it in his 4WD Dodge Van, and he figured he could power the lights on a football field!

[Marc]

I have to agree with DartGT66. I just bought a cop car engine for my truck.
It had a double row timing chain, windage tray, HV oil pump, single springs with dampers, and an oil pan with acceleration and deceleration baffles.
The belt buckle was stamped HP in the right upper corner.
It was a 1977 engine with a cast crank.

[beepbeepsrule]

I bought an ex-Cop car to dismantle once. It was a 1975 Plymouth Gran Fury. It had carpet inside like a supervisor's car, maybe?. It came from Arizona. I drove it a couple of times before I took it apart, the engine seemed very spunky in a car that size. I have not had the engine apart yet. It did have a huge alternator with strange-to-me bracketing. It also had the line cooler on the power steering pump line. It also had an oil cooler mounted on the wheel well that was plumbed from a tee on the oil pressure guage sending unit and dumped back into the block through a hollow bolt that was used as one of the fuel pump mounting bolts. Pretty weird. I will try to get a good look at it this weekend and check out the crank and heads.

[shelbyz]

I don't know anything for sure. (It's seems to be that way a lot for Mopar things.) I would imaging that the Police 400 engine would be coded as a "P" in the VIN. That is the designation for the 400 HD as it's seems to be called out in all the literature. I''m not sure what was different internally as I have a P code 400 in my '78 Magnum. This engine was available to the public but according to the info I've found, to get it in a Magnum in '78, you had to have the towing package. This came with all the heavy duty stuff. My car has an external transmission cooler (in addition to the stock style radiator cooler), three core radiator, small power steering cooler, and as you guys have mentioned, the 100 amp alternator. It was specified because of all the extra electric stuff the cops need. (Radio, lights, siren, etc.) Believe it or not, most of the mid to late 70's Mopar that had a rear window defroster had the external fan 100amp alternator. The info I've found for the P code 400 was that it came with dual exhaust and was rate at 240hp. (net)
If I finish pulling mine out some time and get it torn down (it has a rod knocking) I'll let you know what I find.

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John M. Fleck
DaimlerChrysler Engineer
Kokomo, IN