my understanding is you are correct on the mass of 318s but a police pursuit engine had different specs with upgraded internals. such as full groove main bearings/ HV oil pump, full time oiling to rockers with #2 & #4 cam bearing having a full groove, sodium filled exhaust vales, double roller t-chain plus the oil/trans/PS coolers and 3 core rad-HD 5/8" shaft 8 vain wp, 7 blade thermo-clutch fans

on the cam bearings I have not been able to source a new set as of yet and have only found them in a police code engine. the engine I got from Larry confirms this as it was a roller block with a flat tappet cam which is correct for the 89 4v 318 police code engine. IIRC the cam had .410 lift on intake but defiantly not a mass 318 flat tappet

I printed out some info on head casting #s and engine specs. it shows this 89 4v police engine as having 177 HP @ 4800 rpm where a normal 318 was 150Hp @ 4800 also showed that it was pre-magnum open chamber swirl port 360 heads with #308 castings and they ones I have on my engine. ( I forget the other head casting #s Imwill recheck them)

that may also be where the slightly smaller measurement of the 360 port size comes from with the later model 360 swirl port open chamber heads. as the 915 intake talked about earlier was on the 89 police engine I have. gave that intake to member (locomotion)

so the early non emission 360 heads 72-84? have the larger port opening and are not a swirl port chamber and the late model #308 heads where labeled as swirl port chambers along with the #302 head introduction in 85. 360 went roller cam in 89-91 so that may be when #308 head came out? but either way the #308 pre-mag head is the best one to find but prone to cracks.

With the 340 cam the 318 IS a low comp 340 just 22 less cubes

I agree> a 318 will rev and do what a 340 does if geared right. if you have a 340/3.55 gear = 318/4.11 gear but that is after a cam/head/intake/carb/exhaust swap LOL!

.410" lift is the spec for a 360 cam. Might be misremembering? Or someone swapped in a 360 cam? I have a stock 360 roller cam I had kicked around putting into my 87 318, but I think I'll just get a newer design cam with more lift rather than fool with the stock 360 cam.





Well, 4bbl vs 2bbl would likely be the difference between the HP numbers.




I think you may be right on the port size difference.

Wrong. 78-83 318 4bbl engines got the 4173915 intakes with 1x2 inch runners. I just sold the one I had. 78-80 360's had them as well.

well I just removed one from my 89 police engine replacing it with the RPM Air-Gap intake. this engine was untouched from Larry's ex police car. I don't recall the first digits but last 3 were indeed 915

yes LOL! 2v vs 4v ratings kinda like gross and net ratings but really apples to oranges.

78-83 used a thermobog and 85-up 3184v used a q-jet till the end of pre-mag engines so 78-83 360 heads would be the non swirl port open chamber heads (maybe port size change in 78 and stayed 2" even when going to swirl port technology? that would keep a 915 intake. only difference I see on the 2 different intakes, is how the choke heat well is shaped/milled or molded away on the later feed back q-jet carbs vs thermobog intakes that use it.

but biggest thing I learned wrenching is never say never with mopar, they used up a lot of left over odd & end stuff piecing things together just before going to the magnum engine across the board.

when in doubt measure again.

What was the casting date on it? That would settle the issue.

I have the original 79 lil red express truck intake (360) and I’ll check the numbers tonite. And measure too

Ok got pics if needed. Cast date, 2/6/79 360 intake # 4100340-2. Cast date 10/1/71 340 # 3614025-1. Both ports are the same size.

The casting date on my manifold was 3-26-81. Casting # 4173915. I was replying to Gtxxjon who stated that they never made a small port 4bbl intake for LA 318. I went through this crap right here on this forum 3 years ago trying to figure out what I had. I had never seen a small port spread bore intake before, so I looked up the casting number info and it clearly stated that the intake in question was used on 360's from 78-80 and 318's from 78-83. I had always thought that big port intakes were used on Lil Reds and E58 engines.

The intake I showed is off my 79 lil red express, original numbers matching engine

Chrysler of México assembled on 68/70 period a 318 with 4bbls intakes, 340 camshaft and HiPo pistons made specifically for this engine and used on their Dart GTS versión ( yes, 70 too ). Advertised as a 270 HP engine. Can't tell which heads or some other details. These engines were later exported to Venezuela and Chrysler of Venezuela installed them on 70 Coronets and 71/72 Charger assembled locally, all badged as R/Ts.



On lates 70s USA offered 318 with 4bbls on M, F and B bodies for Cali. Not just police cars.

I think the smaller 2" port size may also be due to push rod hole size. it got bigger for roller cam & shorter PRs. and this also made the dogleg in the intake runner a little more of a restriction in flow.

4323354 on my ‘89 Diplomat Police “ELE”

Attempted to rotate pic