Flow numbers

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rod7515

rod7515

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Can anyone tell me what the flow numbers are on a set of 915 J heads that have the large valves. What can they flow with some port work? Exactly what do they do to port heads?
Thanks
Rod
 
Stock is around 210 cfm, light bowl work and gasket match around 230ish, heavy bowl work, short turn work. Guide profile, and deep gasket match with pushrods pinch worked 260ish, 2.05 to 2.08 valve, tubed pushrod pinch, max bowl roof work about 280cfm. This is all with a top notch 4 to 5 angle valve job and good nailhead ferra or equivalent 5/16" stem valves
 
Varied indeed, and if you want 'from the factory 2.02 heads' flow numbers...then you need to ask someone who actually is old enough or in this game long enough to obtain a set of next to never run 915 2.02 j heads. Mine flow 225-228 depending on port, from the factory with tulip valves.
The 1.88 version j flowed 210-215cfm.

Without push rod pinch tubing they will go to 290's if the porter knows what he's doing.
Experience is everything.

As for what they flow mildly ported? -high 230's to low/mid 240's
 
Hebrews10:26 said:
Varied indeed, and if you want 'from the factory 2.02 heads' flow numbers...then you need to ask someone who actually is old enough or in this game long enough to obtain a set of next to never run 915 2.02 j heads. Mine flow 225-228 depending on port, from the factory with tulip valves.
The 1.88 version j flowed 210-215cfm.

Without push rod pinch tubing they will go to 290's if the porter knows what he's doing.
Experience is everything.

As for what they flow mildly ported? -high 230's to low/mid 240's
Click to expand...

Boy thats true. Can hardly find a set of factory 2.02 J heads that aren't all ready messed up these days. And when you do, half the time they're cracked.
 
I always see guys paying a premium for the J's with 2.02, I would rather have the 1.88 J and cut it for a 2.02 this way the valve sits nice and high in the chamber.
 
ok, thnaks for the information so far, guess I will ask the stupid question and what does push rod pinch tubing mean? Ive never worried about head flow before so all this is new to me. The j heads I bought someone has gone into and cut the ports and it appears to be somewhat sloppy work. Can that hurt the actual flow? Im going to start with them and if I have issues once I am up and running I will look for another head set as a change. I am building a stroked 360 and plan on using a Comp roller with solid lifters, 308 @ .050 .575 lift, An edelbrock 2x4 setup. I didint want to spend the extra on heads at first but now Im thinking maybe I will end up with something different in the long run.
Thanks
Rod
 
ok, thnaks for the information so far, guess I will ask the stupid question and what does push rod pinch tubing mean? Ive never worried about head flow before so all this is new to me.
Click to expand...
This is what mine looked like when i stared the posses

UNLESS YOUR DOING A MAX PORTING AFFECT, THIS IS NOT NECESSARY
attachment.php
 
skrews said:
Boy thats true. Can hardly find a set of factory 2.02 J heads that aren't all ready messed up these days. And when you do, half the time they're cracked.
Click to expand...

I've come across a set or two that were cracked, the 340 block they were on however was worse, and the head cracked right on the deck due to blown head gasket between cylinders , but hell any head would if it were ran like this bozo did.lol.

As for messed up with or messed with , heck yeah, everyone thinks they can grind on a head and it will instantly flow gang busters.
 
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