302's with 1.88's... thumbs up or thumbs down, lets see your pics

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MOPAROFFICIAL

MOPAROFFICIAL

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A lot of guessing in the realm of 1.88 valves put into 302 heads. Assuming nothing.
Post your pics n I'll give you my opinion if they're flowing decent or anemic below .400
Heads up..3 angle vj wont cut it. 4 angle 75 throat plunge or go home is the moral of this story. I'll give some numbers I have and with what done and more pics.
So let's see what you did... and if it runs, let's talk about its performance throughout the mid range...
Go..

20220306_181237.jpg
 
So are you saying a 4 angle valve job is the only thing to do for performance?
 
Mr. Sinister said:
So are you saying a 4 angle valve job is the only thing to do for performance?
Click to expand...
I'm saying when sticking .100+ larger valves in them that without the 4th lower 70 or 75... the bowl/throat will be smaller than stock in relation to the seat angle...and flow terrible. Even just as or more crucial is the deshroud for .100-.300 numbers.
Not only is that cut opening the bowl and transitioning it better... it's also helping the short turn by moving it more upright vertical ridding the over hang.
 
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Well your picture looks like there is no other work visible that is the reason for my question.
 
Mr. Sinister said:
Well your picture looks like there is no other work visible that is the reason for my question.
Click to expand...
Ok, great. So what I've done is.. with stones 'kwikway cool blue, multi purpose black and tan finish stone on the 45'..grind the 4 angle and then hand die grinded the chamber below the short side only as much as 30 degrees as to the top cut but steeper approaching the cyl wall side.
Now I dont want to give any impression that im saying this is the perfect valve job, no, in fact I'll probably play more n take another 75 drop to open it up. Its cracked test head from the videos. I'm more so saying 'after seeing pics here of some others' that this is more so the least IMHO you want to do. I'm doing this as helpful..not an .."I'm bored so let's throw tomatoes at my friends"....its 'here,let me see.. ok this is good... or okay you need to do this...' .
@Mr. Sinister
I'm Justin. What's your name?
 
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Jerry did the same thing with my closed chamber slant head. He opened the bowls up with a 75 I think he said and then finished them off by hand. That old guy is an artist with a hand held. I wouldda cut the damn thing in half. lol
 
MOPAROFFICIAL said:
Ok, great. So what I've done is.. with stones 'kwikway cool blue, multi purpose black and tan finish stone on the 45'..grind the 4 angle and then hand die grinded the chamber below the short side only as much as 30 degrees as to the top cut but steeper approaching the cyl wall side.
Now I dont want to give any impression that im saying this is the perfect valve job, no, in fact I'll probably play more n take another 75 drop to open it up. Its cracked test head from the videos. I'm more so saying 'after seeing pics here of some others' that this is more so the least IMHO you want to do. I'm doing this as helpful..not an .."I'm bored so let's throw tomatoes at my friends"....its 'here,let me see.. ok this is good... or okay you need to do this...' .
@Mr. Sinister
I'm Justin. What's your name?
Click to expand...

MOPAROFFICIAL said:
Ok, great. So what I've done is.. with stones 'kwikway cool blue, multi purpose black and tan finish stone on the 45'..grind the 4 angle and then hand die grinded the chamber below the short side only as much as 30 degrees as to the top cut but steeper approaching the cyl wall side.
Now I dont want to give any impression that im saying this is the perfect valve job, no, in fact I'll probably play more n take another 75 drop to open it up. Its cracked test head from the videos. I'm more so saying 'after seeing pics here of some others' that this is more so the least IMHO you want to do. I'm doing this as helpful..not an .."I'm bored so let's throw tomatoes at my friends"....its 'here,let me see.. ok this is good... or okay you need to do this...' .
@Mr. Sinister
I'm Justin. What's your name?
Click to expand...


I can clearly see 4 angles cut plus a chamber and quench pad relief cut. Nothing wrong with the pics.
 
MOPAROFFICIAL said:
Ok, great. So what I've done is.. with stones 'kwikway cool blue, multi purpose black and tan finish stone on the 45'..grind the 4 angle and then hand die grinded the chamber below the short side only as much as 30 degrees as to the top cut but steeper approaching the cyl wall side.
Now I dont want to give any impression that im saying this is the perfect valve job, no, in fact I'll probably play more n take another 75 drop to open it up. Its cracked test head from the videos. I'm more so saying 'after seeing pics here of some others' that this is more so the least IMHO you want to do. I'm doing this as helpful..not an .."I'm bored so let's throw tomatoes at my friends"....its 'here,let me see.. ok this is good... or okay you need to do this...' .
@Mr. Sinister
I'm Justin. What's your name?
Click to expand...
Frank is my name Justin.
I asked the question about the picture and post because new procedures and products come out and not everyone is aware about them.
I was taught when you going to mod cylinder heads do a good 3 angle and blend the port work into the valve job. So maybe the 4th angle might work or maybe it’s not needed.
This info was passed on to me by a guy named Tim Connelly- cylinder head development for Chrysler and Arrow Racing Engines. I worked at Arrow for a short period of time, I don’t consider myself an expert but reasonably informed.
 
Mr. Sinister said:
Frank is my name Justin.
I asked the question about the picture and post because new procedures and products come out and not everyone is aware about them.
I was taught when you going to mod cylinder heads do a good 3 angle and blend the port work into the valve job. So maybe the 4th angle might work or maybe it’s not needed.
This info was passed on to me by a guy named Tim Connelly- cylinder head development for Chrysler and Arrow Racing Engines. I worked at Arrow for a short period of time, I don’t consider myself an expert but reasonably informed.
Click to expand...
Frank, the title says why. 1.88 in a 302 head. The 60 alone wont cut it and leaves a lot of hand work to be done. That's the clear difference and why I titled it this way... because in general .."modified" could mean almost anything.
I've found also that you plot your 60, you grind/blend the 75/70 to the plotted 60 line...then once you get it blended, flowed, and are happy... you touch the 60 once more to just sharpen it. Seems to be good for almost 20 ft lbs of torque than if you slightly blend into the 60. Of course it depends what head ,for what and so on...then the whys.
Too thin a 45 suck as does too wide.
.060-.045 wide on the 45 and .075-.100 wide on the 60 is usually where I end up on these .
Starts to sound too general/broad a brush. Needed, imo , with a 1.88 into what was a 1.78 seat, but I'm not the end all. Thanks for any/all contribution to this thread.
You must have many pictures to illustrate the 3 angle approach to 1.88 upgrade, looking forward to them.
 
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The peaks are near 1.78 peaks. Underneath the peak is the difference 15-20 cfm, if the seat job is throat cut at least 1.6-1.62 and chamber deshroud-which is still small.
 
Curious to see the end result flow numbers. Everything I have read says the magnum heads flow about about 210 from the factory. You were able to get there with the small 1.78 valve with the 302 head.

Think 240 or 250 will be within reach with the 1.88?

Have you ever flowed a stock magnum head on your bench for comparison?
 
587 heads, legal stockers, 3 angle valve grind, sanded seats, and back cut intake valves sanded to smooth radius, mopar, sst valves,1.88 valves,test at 25 " 211 cfm, 122% port velocity . just food for thought. i don't know how to post pics here.
 
Do you feel valve de-shrouding in the combustion chamber would help?
 
perfacar said:
587 heads, legal stockers, 3 angle valve grind, sanded seats, and back cut intake valves sanded to smooth radius, mopar, sst valves,1.88 valves,test at 25 " 211 cfm, 122% port velocity . just food for thought. i don't know how to post pics here.
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587 castings.
They came 1.88 and open chamber.
The 4th 75 cut would help, but it's not required in that example. 3 angle is great for everything that came with the valve size being used. The factory already cut the 75 and sometimes another 90.
That's not bad, the lower lifts are what I'm curious to see, they vary a lot in terms if peaks. I've had some peak anywhere from 199-208 or so. I'd have to look.
 
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