how to port swirl ports

[duster wonder]

looked at my head casting and 4343923, which is what the interwebs tell me a swirl port head for the 360


The best non-Magnum 360 heads are the swirl port roller cam heads with large pushrod holes that were found on 1988-1992 360 trucks. Look for casting numbers 4448308, 4323352, 4343923 and 4343964. They are commonly called just "308s". Mopar guru Rich Ehrenberg really liked them and said that the chamber and intake port are almost identical to a 340 “X”casting. He also said that the exhaust flows about as well as a W2 race head.

i stole that from another forum and im happy all of a sudden.

but.. how would you port these or should i say improve flow if i should even touch them?

supposedly this means the motor was to be roller lifters.. but theres no lifters in my motor. how does this affect ordering parts? (cam etc)

 

[mopar340dave]

You run whatever type of cam you want to, just make sure the valve springs match.

 

[Prine]

lol....

This is known info......like you just stumbled onto some NEW info....:laughing:

308 casting 360 heads are harder to come by in useable condition than a set of X 340 heads.

I tell everyone, because right now(2012)....is the best time ever to find them.

When the 302 casting was just being scrutinized in 1998/1999/2000 and used on the 406hp 318.....they mentioned the roller cam 360 with LA heads existed.

There had already been some discussion of the 308s on Moparts, but it was limited because the problem was the same across America.......

Roller Cam 360 Engines,...ONLY came from the factory in 1989/90/91 D250/B250 TRUCKS....and 4x4 Ramchargers.

These engines are workhorses.....there are still 89/90/91 trucks on the road here....I see them all the time......and these trucks are just reaching their real service life....15-20 years.

Finding a engine that has had good oil changes, tuneups and air filter replacements, and cooling system maintanence is near impossible.
Resulting in worn rings/bearings, uneven combustion burning, carbon deposits, and cracked heads.

Choose Wisely.


What should be done to pickup some performance from these heads is basic cleanup and gasket matching....and like said above,....matching valvesprings for your camshaft.

 

[Prine]

Your also going to need to seal up the Smog Ports. I recommend the welding method.

Does your engine look like this?

This spider and the raised lifter bores with the cutouts for the dog bones around 2 ROLLER lifters makes it a roller cam motor.

Ordering replacement roller lifters is no big deal....roller 318/360's use the same hydraulic roller lifter.....87-92 318....chrysler fifth avenue's all day....autozone probably stocks them and the pushrods.

 

[redlined]

Roller Cam 360 Engines,...ONLY came from the factory in 1989/90/91 D250/B250 TRUCKS....and 4x4 Ramchargers.



Including D/W350 series.

Which brings up my question. I have a set of '90 308's, {from a low mileage W350} and the push rod pinch is horrible due the oversized pushrod hole. I can't get my index finger past the first knuckle, the port cross section looks no bigger than an early 318, and the hump is almost 90 degrees flat looking in the manifold side.

As you have surmised, I've never read a helluva lot about these heads, are they that good with some cleanup? Any links for the uneducated?

 

[Prine]

Including D/W series 350's - CORRECT.

only installed on a truck chassis...D250 or Ramcharger 4x4 minimum requirements though.

I have seen some conversations about porting them, and a few about what the heads flow......and quite a few people have strokers using a Roller Cam 360 as the foundation....I cannot provide any more links or useful information.

My 74 Duster is using a 89 Roller Cam 360, 308 headed longblock in stock configuration,
pistons, rods, crank, camshaft, heads all STD....just reconditioned....for a Single Turbo Application.

Should be Fun!

 

[1wild&crazyguy]

the 308 w/2.02 valves flows the same as a 915/894 X/J head, the exhaust has a lil better 'few cfm' low/mid lift flow but in stock form still flows the 140's cfm that the old heads flow.
If you work the roof a lil and bowl of a 308 exhaust port, the exh numbers go up quite a bit.
The pushrod pinch of the 308 head sucks, but it does speed up air...so even tough the 308 w/2.02 int valves flows the same 225-230cfm that a J/X w/2.02's does...it could possibly help a hair in the velocity depot.

ultimately....ask urselves 'where are all the ported 308 heads that flow 280+cfm?'

Do you know anyone who has a pair?
How many of those heads have cracks?

I have a pair of them, they arent ported...yet....but im not sure i would go max effort with them , not at this point at least.

I say if 250/185 cfm int/exh is what ur looking for and those r the heads u happen to have....then ur good. It would take very lil work to get them there 'same work as old heads on int' and even less work than the old heads on the exh.
fwiw

 

[redlined]

Don't mean to hijack, my aplogies to the OP, just saw this thread and it's in line with what I have going at the moment as well, so I thought I'd ask a few questions about these heads, with Duster's blessing I hope.

Looking at the severely pinched intake ports I assumed they were some lousy flowing heads with no quench in the chambers, and had written them off. My application isn't high RPM performance oriented,{4800 max} but rather a TBI motor with strong low/mid torque for my Ramcharger.

One more question and I'll leave the OP to his thread. Are these heads prone to crack between the seats like early Magnums? Do I need to be wary of overheating these heads wheeling here in the desert? I haven't had any problems with the current 360 getting hot, but the more I'm aware of the shorter the walk home will be.

 

[Mopar44134]

an akron cl ad had a set for 50 bucks. of course just picked up while i was reading the ad.

 

[kennygene]

WHy not just pick up magnum heads? They are pretty cheap nowadays and have closed chambers.

 

[duster wonder]

my oil valley didnt look like that but the head casting says what i posted up top so... its not a roller cam

came out of a 87 pick up

as for flowing im just going to smooth some stuff out, such as the letters in the runner, and the gigantic push rod flow contrstrictor thinger dingers, and weld up the smog holes

ive heard to use 1.6 rockers on the intake only, leaving exhaust at 1.5.. beacuse on 308 heads the exhaust almost opens too soon which in long story short your fuel could be burned in the headers and nobody wants that. then i thought well thats the cam not the heads ha

 

[racyroy1]

I read this, went outside and checked my 89 heads and wouldn't ya know it they have the casting 4448308,,,, so i guess i have a good set. I had to throw the block away due to the clown that sold it to me said it was good but I found a crack in the lifter valley, and i had to put her down. So I guess i can start the slow process of port and polishing them.

kevin

 

[jimjimjimmy]

i know a guy that runs 10.80s in a 73 cuda street car with a 308 headed 340 and a solid comp cam and 273 rockers and it pulls hard to 7000

 

[RustyRatRod]

Just run more nitrous. Then it won't matter which heads you got.

 

[1wild&crazyguy]

fwiw, most sbm heads when pulled off of later fuel injected motors will have a high probability of being cracked. They run leaner-hotter and when sensors fail as well...poof