360 head porting for big power (500HP ?)

-
valve job

IMG_0204_zpsdff68f18.jpg


deshrouding cut added

IMG_0203_zps0db8532c.jpg
 
An old J head was ground to water and filled with epoxy to achieve the desired result,then it was given to the pencil pushers to use as they saw fit,much of the potential was left out of the production piece.
 
I can't tell from the pic but have you thought of using a radius exhaust seat?
 
on the bench for the final time

IMG_0281_zps7f1adcef.jpg

.........ex1.......ex2........ex3........ex4
.050--21.........21.........24..........24
.100--46.........45.........48..........48
.150--73.........70.........83..........80
.200--92.........87.........114........107
.250--117.......108........141........129
.300--137.......126........165........150
.350--156.......139........184........163
.400--169.......150........195........171
.450--178.......159........205........176
.500--182.......162........208........180
.550--184.......163........208........180
.600--184.......164........209........180

ex1-out of the box with OEM valve flowed with 1.75 pipe
ex2-out of the box with OEM valve flowed with out pipe
ex3-fully ported, REV semi tulip valve, valve job and deshrouding cut flowed w/pipe
ex4-fully ported, REV semi tulip valve, valve job and deshrouding cut flowed w/o pipe
 
Again, nice low lift numbers.

These were actually truck/van heads, those vehicles never saw north of 4 grand. Wonder if the low lift numbers here are evidence that the engineers knew these would be for low RPM applications.

Just a thought.
 
Beautiful work! Never seen 302 castings go more than 250-ish. Never seen a valve guide boss eliminated,before. Nice attention to all aspects. Nice match,with the cam.
 
Abodybomber said:
Beautiful work! Never seen 302 castings go more than 250-ish. Never seen a valve guide boss eliminated,before. Nice attention to all aspects. Nice match,with the cam.
Click to expand...


These are not '302' 318 heads we're discussing, but rather the '308' 89-91 roller 360. Precursor to the Magnum head.
 
Fair enough. I don't usually use stock castings anymore,thanks for the info.
 
Way back when I had my 360, its "J" heads I had flowed at 484hp, I think you could have gone further with them. That motor was very healthy indeed.
 
skrews said:
on the bench for the final time

IMG_0281_zps7f1adcef.jpg

.........ex1.......ex2........ex3........ex4
.050--21.........21.........24..........24
.100--46.........45.........48..........48
.150--73.........70.........83..........80
.200--92.........87.........114........107
.250--117.......108........141........129
.300--137.......126........165........150
.350--156.......139........184........163
.400--169.......150........195........171
.450--178.......159........205........176
.500--182.......162........208........180
.550--184.......163........208........180
.600--184.......164........209........180

ex1-out of the box with OEM valve flowed with 1.75 pipe
ex2-out of the box with OEM valve flowed with out pipe
ex3-fully ported, REV semi tulip valve, valve job and deshrouding cut flowed w/pipe
ex4-fully ported, REV semi tulip valve, valve job and deshrouding cut flowed w/o pipe
Click to expand...
I like what your doing I haven't had the urge to work that hard on factory iron in 20 yrs but I think you have way more head than needed for only 500hp. Good luck.
 
goldmember said:
I like what your doing I haven't had the urge to work that hard on factory iron in 20 yrs but I think you have way more head than needed for only 500hp. Good luck.
Click to expand...
Thanks pal. I started these things about 3 years ago. They were originaly intended for my 10 second street/strip pump gas 360 engine build http://www.forabodiesonly.com/mopar/showthread.php?t=216720, but then I wound up putting a set of IndyBrocks on that. Every time I started in on the task it seemed endless :banghead:, so it got drug out then shelved. Fast forward to last year about this time I built my spare parts 360 http://www.forabodiesonly.com/mopar/showthread.php?t=198914. Ultimately made 442HP with that thing. Then the wheels started turning. Knowing that the heads and cam were the major limiting factors on that motor, I dusted off the 308s and got back at it.
 
Did you ever get the chance to try these heads on the engine? How well would a set of 587 heads respond to alot of these mods, especially the guide boss/guide work? By the way, these heads look awesome!
 
Damn skrews, how did I miss this? Awesome work buddy.
 
RustyRatRod said:
Damn skrews, how did I miss this? Awesome work buddy.
Click to expand...



x2. I'll have to see the pics when i get home. I'm also a user of flow directing veins on the intake side - it's why I shape the guide boss rather than removing all of it.
Is the engine running yet?
 
Heads are sitting on the bench. I added an 86* throat cut to the intake port, which really opened up bowl. I have some brass tubing coming in next week to tube the push rod holes. Should gain about .060" in the push rod pinch. I'm hoping these mods push the peak flow into the 290+ range. I'll update when I get there.
 
SKREWS, do you think you could gain more by filling the pushrod holes, redrilling for T/A style offset pushrod set-up and removing the hump in the intake ports?
 
69MOPE said:
SKREWS, do you think you could gain more by filling the pushrod holes, redrilling for T/A style offset pushrod set-up and removing the hump in the intake ports?
Click to expand...

Yes. Infact Mopar used to have a 308 style head that was done that way OOTB about 10 years ago.
 
skrews said:
Yes. Infact Mopar used to have a 308 style head that was done that way OOTB about 10 years ago.
Click to expand...

I will attempt what you have done and also do the pushrod relocate. Pictures to follow. Thanks for the great pictures.
 
You must log in or register to reply here.
-

Back
Top