Intro to a port job

-
Mopar
I know your past this but would a larger valve cut down with a 30 degree seat sitting on the current top cut height work (assuming .5 inch lift cam max)
only way I saw to save without seats
I'd have to have a 15-22 degree top top cut then narrow and open up the old 45 and the rest with the Serdi
 
Wyrmrider said:
Mopar
I know your past this but would a larger valve cut down with a 30 degree seat sitting on the current top cut height work (assuming .5 inch lift cam max)
only way I saw to save without seats
I'd have to have a 15-22 degree top top cut then narrow and open up the old 45 and the rest with the Serdi
Click to expand...
2.08 valve , yes.
They are sunk .060 deep into the chamber with a ledge around it. Can they be saved? Do it all over again, new bigger valves, clever chamber side radius cut...How much you wanna spend? What is the number 1 goal?Then after that, the porting. Only if they were the last set of heads on earth would I even bother. They're a black hole in terms of time/money vs return.
Killer6 said:
Is there even enough meat in a 308 bowl to support a 2.055" unit???
Click to expand...

How much effect on the combo do you want impose in order to make something work. He could probably fair swell with 1.94 intake valves with what he is doing and target #....so 2.05? Unfortunately.. the seat is sunk .060... then there is the valves head margin outside of that. You can see about .015-.020. gap around the valve head and surrounding chamber ...so maybe 2.08 would be perfect. Ay...yeye get what I'm saying?
You would spend twice to have what...?
To hell with playing mad scientist or machinist expert, nothing to prove...the guy already spent on these heads and they're fucked up. He would not be of sound mind to put another $400 + into these things. 2 shops have looked and said...no thanks, just get another set...they are not special.
Anyone traveling back east from the west coast ,near me, and could take these back to Randall, let me know... because paying the shipping isnt worth it. I want him to have them back so he can toss one through the window of the shop that ruined them.
I'd be pissed if I were him... though as soon as I laid eyes on them at the counter I would have put my wallet away and asked the guy for a new set of heads before I took him to court and had 3 other shops outside of town give written report of the heads even it cost me the tear down. The guy screwed him.
 
The core 348915 heads fresh off the gasket, adding more pics as I take them.

20190516_181319.jpg


20190516_150940.jpg
 
thanks official
I had to save a set of chevy/ buick heads that were similar
lucky to have had the serdii and all the cutters
heads ended up at Bonneville
I did not do the porting so I have no idea how they came out
I use 30 degree seats a lot on low lift motors but as you said you have to open the chambers- which I usually do anyway even on 45 degree seats
 
Some pre machine shop work.
I use orange spray paint with a stock felpro gasket aligned and taped down to gasket match. I also open or thin and shape... the 'push rod pinch' later in the game as needed. The picture with the one short turn done is something I did for fun, to see what it does with the 1.88 stock vj while semi heavily ported.. and short mildly ,tee hee.

20190613_143213.jpg


20190613_143201.jpg


20190613_140917.jpg


20190613_143158.jpg


20190613_140935.jpg
 
Last edited:
That’s an interesting bowl shape, to say the least. It appears to make swirl/tumble in the cylinder by manipulating mixture velocity around the circumference of the valve. Just curious as to how much material is in the bowl to port before running into water in those and if you ever band sawed or sonic checked to see. Very curious as to what it flows like that, too, it looks like it may be better than expected.
 
Garrett Ellison said:
That’s an interesting bowl shape, to say the least. It appears to make swirl/tumble in the cylinder by manipulating mixture velocity around the circumference of the valve. Just curious as to how much material is in the bowl to port before running into water in those and if you ever band sawed or sonic checked to see. Very curious as to what it flows like that, too, it looks like it may be better than expected.
Click to expand...
Everything looks different with different camera angles...plus the short is just blended some. Ever look at an edelbrock head, the head bolt before the short side, the bump it is in the straight wall?
 
What would you say the bowl to seat percentage is on that intake port? What's a good percentage to have there?
 
Garrett Ellison said:
That’s an interesting bowl shape, to say the least. It appears to make swirl/tumble in the cylinder by manipulating mixture velocity around the circumference of the valve. Just curious as to how much material is in the bowl to port before running into water in those and if you ever band sawed or sonic checked to see. Very curious as to what it flows like that, too, it looks like it may be better than expected.
Click to expand...
**1.88 tulip 'as cast' intake flow is**
Cfm@28" temp66/73% humidity 500ft
.100 52.7
.200 115
.300 166.4
.400 194.6
.500 187.2

**1.88 tulip initial port work shown w/short turn work on straight wall hump
Cfm@28"
.100 67
200 128.5
.300 186
.400 215
.500 243
Starts to saturate at the typical .530-.550 with it peaking @246
I could work on fixing that.. but these are getting 2.02 valves and I'll save it for another day. I just wanted to have a little fun with the 1.88 stock 3/8 stem valve..not bad for just port work and no seat job, compare to average 2.02 numbers. A 1.94 would make little work to have a nice 255cfm head... but the way the short turns are cast...you have 2 options imo...1 is to lay it back really far to get the even parting line, the other is to just put a bigger valve in it and you only have to lay it back so far with the other work that's already been done. I'm just small talking over a beer now.. anyways ..it's always interesting and fun. I need to do a vid or 2, or live feed er something.
 
Last edited:
MOPAROFFICIAL said:
**1.88 tulip 'as cast' intake flow is**
Cfm@28" temp66/73% humidity
.100 52.7
.200 115
.300 166.4
.400 194.6
.500 187.2

**1.88 tulip initial port work shown w/short turn work on straight wall hump
Cfm@28"
.100 67
200 128.5
.300 186
.400 215
.500 243
Starts to saturate at the typical .530-.550 with it peaking @246
I could work on fixing that.. but these are getting 2.02 valves and I'll save it for another day. I just wanted to have a little fun with the 1.88 stock valve. A 1.94 would make little work to have a nice 255 cfm head... but the way the short turns are cast...you have 2 options imo...1 is to lay it back really far to get the even parting line, the other is to just put a bigger valve in it and you have to lay it back so far. I'm just small talking over a beer now.. anyways ..it's always interesting and fun. I need to do a vid or 2, or live feed er something.
Click to expand...
Why does THIS graph of lift progress in gradual increments of flow increase as the valve opens (which we would expect) and then some lift flow numbers have near matching flow for .300 AND .400 with a tremendous taper off (falling flat in flow increase) between .400 and .500 (or something similar)?
THANKS for teaching us!!!
 
Last edited:
Post #105 second picture is that a crack in the chamber in front of the spark plug hole above the intake port?
 
greymouser7 said:
Why does THIS graph of lift progress in gradual increments of flow increase as the valve opens (which we would expect) and some lift flow numbers have near matching flow for .300 AND .400 with a tremendous taper off (falling flat in flow increase) between .400 and .500 (or something similar)?
THANKS for teaching us!!!
Click to expand...
Great question, one I would have asked way back when but would safely assume now... well, Because I didnt really finish the short turn for this valve and turbulence takes over pulling the air to one side and no longer flowing more air. Specifically the straight side short. I ground down the wall hump and went into the straight wall in the process... but then you need to position high in through the port window and grind down toward the valve/bowl and make the shape that completes the other dog leg side short. Maybe I'll continue, but I'll have to do it all over again when the 2.02 is in like I said in that post you quoted. We could see much more if this was the finish valve size.
As for the part about near matching .300 and .400 numbers? Are you referring to the 2.02 numbers posted from the other heads or?
The increase over stock 'with same valve' flow is...
.100 +15
.200 +14
.300 +20
.400 +21
.500 +54
These 348915 heads with the work done to this point ,as is, are better than those 2.02 308 with the 'suck ***' valve job we started out with even after porting. Sunk is junk.
 
Last edited:
Thanks for sharing! I look forward to your postings and what you come with next, wish ChryCo had made the chambers like the 302 heads.
 
Looks like a lot of good potential for a street 318 with a heavy mill cut, 1.94/1.50 valve retrofit, and associated porting.
 
Garrett Ellison said:
Looks like a lot of good potential for a street 318 with a heavy mill cut, 1.94/1.50 valve retrofit, and associated porting.
Click to expand...
Honestly if I was doing a street 318... I would port a set of 318 heads. Beyond 375 hp is beyond 318 cid for "street".. build more cubes at that point is what I think about that. And putting a seat for a 1.50 exhaust in an LA 360 is not what I do...
I would just use a 318 head.. on a 318cid.
 
depends
we could but that exhaust 1.5 seat in slid over to the outside .050
that would give us .100 more between the seats with intake in the stock location
now we could put in a much larger intake valve (depending on the bore)
at least .100 larger depending on the combustion chamber shrouding or unshrouding
nice article MOPAROFFICIAL
agree on the smaller, higher velocity 318 head (now which) for street builds (not to go with big headers) or big intake
 
Agreed, the more I look at my 675 318 heads the more overall potential I see being able to reuse them.
 
This is a pic of what a ported 1.88 915 looks like after the 1st 2.02 45 degree seat is cut, no plunge. From there the lower 60, 75 and then the top chamber 30 degree narrows to the proper seat width of .050
Follow up pics of finished will be next and then some final massaging.

20191023_183201.jpg


20191023_183332.jpg
 
Curious to know how do 308 heads compare to the x heads? I've also heard j heads flow better on exhaust than X-heads?
 
QuickDart360 said:
Curious to know how do 308 heads compare to the x heads? I've also heard j heads flow better on exhaust than X-heads?
Click to expand...
The intake port of an X head is slightly different from a j or any other prod. LA head. There is a lot less of a hump coming off the wall and the turn has a longer approach ramp. I wanna say I really see no difference in the exh port between the two j & x. Imo the 974 has thee best exhaust port because they Incorporated the air injection bosses and right next to the ssr unlike later versions that are a good 5/16 or more away from the exh ssr. 308 IS a great exh floor shape...but imo the port is too small. If you want to do LESS WORK and run into LESS PROBLEMS with TOO MUCH AIR SPEED...you would port an x head over a 308 head.
 
You must log in or register to reply here.
-

Back
Top