360 head trip

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I have a set of #974 360 heads with 1.88/1.60 valves in them on a 3 angle low mile valve job and figured I'd do a set by step 'w/before & after testing' sb iron head porting thread.

Here are the as cast INT port numbers for these 974's
.LIFT---CFM
.100.....55
.200.....109
.300.....169
.350.....193
.400.....206
.450.....213
.500.....208
.600.....203-4

I will do just the short turn/bowl then retest, then the guide, the roof and the pinch with a retest after each.
I should have the 1st test today/tonight and see what a lil bowl work does and how long it takes.
Side note: these heads dont have as tall a short turn as the '915 version
Just a couple of pics of what im working with.
 

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Good deal, real world tech, this site needs more of stuff like this.
A step by step, how to, would be awesome as well, for us "never done thats".
Have your own flow bench, I assume?
 
Good deal, real world tech, this site needs more of stuff like this.
A step by step, how to, would be awesome as well, for us "never done thats".
Have your own flow bench, I assume?

Thanks, and yes I do have my own flowbench.



Awesome!

Are you going to do EX too?

And some close up pics of the work would be great.

Yeah I will do the exh last, just figured I would do a lil work at a time and post results.


So I blended the bowl some and laid the short turn back a lil, all from the chamber side of the port and just basically blended what I did into the as cast roof/guide/walls , but since I only worked it from the chamber side...there is still more to be done in the depot of blending the ssr to floor-theres a lil lip.
Here are the numbers before and after
-LIFT--------CFM
.100-------55---56----+1,lol
.200------109---111--+2
.300------169---176--+7
.350------193---198--+6
.400------206---213--+7
.450------213---221--+8
.500------208---230--+22
.550------204---225--+21


It's decent for 15 minutes of bowl blend work.

Sorry if the pics suck, Im not suited to take up close pics.
Im using a combo of cannon & macbook shots.
 

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Looks good, doesn't seem like much, but what you did was worth 10-20HP... that's a big difference.

Just gettin started.:happy1:

I just rounded the bowl some, a lil working of a path from the valve guide to the seat on the far side bowl, layed the ssr back and up the the straight wall a lil, just to the peak...barely anything done and very conservative.

Once the guide is slimmed/profiled and the straight wall to bowl is worked it should start to come to life.

the other thing is the gigantic sky jump on the stock int valve, dont now if there is a enough face to remove it all, but I bet if it wasnt there...there could be another 5'sh or more cfm thats already there.

once this port is mostly done, maybe a fresh perf VJ will be done....then test again..
Maybe a 11/32 guide and cut down nail head valve to try out on the bench.
 
ski jump?
Are these tulip or nail head 1.88' intakes?
 
Wanna slant head to experiment on?
 
Ok...I was able to do some more work on them today, I basically wanted to do some guide work, not full blown and done, but just to neck it down some to widen the straight wall/guide area just above the ssr.
The kink in the roof is gone and the straight side section of the guide is slimmed and pointed toward the port window, however the far side portion of the guide is only half way done, as in I did not work between the far wall/bowl and guide...yet.
I also rid the ssr peak of the sorta lip it had by going through the port window to reach it.
The roof is stock minus the kink removal, no push rod work or floor work till the ssr, just a bowl blend/ssr laid back some/roof kink and a lil guide trim.

here are the latest numbers
.100---55.3
.200---111
.300---176
.350---198
.400---213
.450---224
.500---235.3
.550---240.7
.600---243.2


-LIFT------------CFM
----------stock---bowl/ssr---guide/roof kink
.100-------55------56----+1-----55.3-------
.200------109-----111--+2-----111----+2
.300------169-----176--+7-----176----+7
.350------193-----198--+6-----198----+6
.400------206-----213--+7-----213----+7
.450------213-----221--+8-----224----+11
.500------208-----230--+22---235.3--+27.3
.550------204-----225--+21---240.7--+36.7
.600------***-----***--***---243.2---+43
Gains based on stock flow*

At this point it's gonna take a good valve job and valve back cut to bring the lower lift numbers up, and those 2 things will definitely do just that by a considerable amount.

I will post pics later, maybe tonight, I was eager to see the result and just flowed it 1st.
 
Justin, posting good pics will help a lot on this site..... I'm glad you are doing this, show members here how doable it is. (And you added another 40-50HP from a stock head doing basic porting anyone can do)

Two thumbs up!
 
what valve angles would you suggest for for a .500 lift cam after lash? at this point would you gain much with a 2.02 valve and bigger bowl over the 1.88? i wonder about the bigger valve shrouding and and slowing air speeds. not an expert by no means just wondering thanks.
here are the latest numbers
.100---55.3
.200---111
.300---176
.350---198
.400---213
.450---224
.500---235.3
.550---240.7
.600---243.2




At this point it's gonna take a good valve job and valve back cut to bring the lower lift numbers up, and those 2 things will definitely do just that by a considerable amount.

I will post pics later, maybe tonight, I was eager to see the result and just flowed it 1st.
 
Another neat little trick is to put a 1.94 chevy valve in it. Not quite the 2.02, but gives you some fresh meat if the 1.88 is sunk a bit and some more effective area.

Interesting what gains you can make with some time and careful porting.

Wear a respirator and ear protection if you undertake this and care about your health... :)

Nice work Justin! :thumbup::headbang:
 
what valve angles would you suggest for for a .500 lift cam after lash? at this point would you gain much with a 2.02 valve and bigger bowl over the 1.88? i wonder about the bigger valve shrouding and and slowing air speeds. not an expert by no means just wondering thanks.
[/QUOTE]

Well valve jobs is something I dont do and farm out to others.

Typically a 70/45/30 3 angle would work nice, but there are some who use 5 angles.
The top cut some do 'chamber side' would make a nice radius transition from the seat angle to the chamber but requires loweering/sinking the valve job some.
Some 'like pontiac' go with a 30* seat cut to pick up low lifts, for at the same cam lift you see a greater gap/distance between the valve & seat and there have been test to show that a 30* helps flow more in the low...but down side is the valve job is said not last like a 45* because the seat gets hammered more a t that angle....so they say..

I have heard 2 conflicting things from 'pro' porters, one is that the sbm wedge like the valves sunk some, the other is that sbm wedge heads dont like the valve job sunk.....LOL

I haven't purposely gambled a head trying to sink the VJ yet...but might give it a shot on a lonesome mismatch head at some point to see.
The other side of this is the justification of sinking the vj for that chamber side cut is that the loss is offset, but is this with all lifts? I dont know...I'm still learning and and am going with what I know works, or should work..
 
Justin, posting good pics will help a lot on this site..... I'm glad you are doing this, show members here how doable it is. (And you added another 40-50HP from a stock head doing basic porting anyone can do)

Two thumbs up!

Thanks, just having fun and trying to help somebody.:headbang:

And the better pics are coming soon..
 
Another neat little trick is to put a 1.94 chevy valve in it. Not quite the 2.02, but gives you some fresh meat if the 1.88 is sunk a bit and some more effective area.

Interesting what gains you can make with some time and careful porting.

Wear a respirator and ear protection if you undertake this and care about your health... :)

Nice work Justin! :thumbup::headbang:

Thanks bro.

:happy1:You know me, I like to mess with boat anchors.LOL
 
Another neat little trick is to put a 1.94 chevy valve in it. Not quite the 2.02, but gives you some fresh meat if the 1.88 is sunk a bit and some more effective area.

Interesting what gains you can make with some time and careful porting.

Wear a respirator and ear protection if you undertake this and care about your health... :)

Nice work Justin! :thumbup::headbang:
and eye protection,take it from me.and great thread,some stuff us poor guys can use
 
Are you going to shorten the length of the V/guide? All the F.A.S.T. SB heads i have seen are very short with the bronze guide sticking out. Also would be nice to see this head if your ging to all out port in a 2.05/1.62 size since many of us are going to 416.426/440+ sb's
 
I took a few but this camera aint where it's at.
I have better luck with a led light and the camera on my lap top...
 

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Ah old school **** style photography... a lost art. :)

Fuzzy, grainy and can't make out the details. You tease.
 
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