Posted By: elmor353
915 and 516 CC's - 04/07/14 10:02 AM
Can anyone tell me how many cc's the combustion chambers are on these heads? 
915 and 516 CC's
Posted By: JohnRR
Re: 915 and 516 CC's - 04/07/14 03:15 PM
915's run about 84cc if I measured right , 516 ??? Do NOT use NHRA specs, they are smaller than actual.
Posted By: Mr.Yuck
Re: 915 and 516 CC's - 04/07/14 03:22 PM
Quote:
915's run about 84cc if I measured right , 516 ??? Do NOT use NHRA specs, they are smaller than actual.
I though they were like 78
Posted By: JohnRR
Re: 915 and 516 CC's - 04/07/14 04:24 PM
Quote:Quote:
915's run about 84cc if I measured right , 516 ??? Do NOT use NHRA specs, they are smaller than actual.
I though they were like 78
That's the NHRA spec and it is WRONG
NHRA spec for 906 is 79.5 cc ... WRONG
Posted By: dogdays
Re: 915 and 516 CC's - 04/07/14 05:04 PM
They typically measure out to 84cc, just like the Edelbrocks with a similar chamber.
R.
R.
Posted By: ademon
Re: 915 and 516 CC's - 04/07/14 06:03 PM
Mine were right at 80 but I'm sure the heads have been milled to clean, this was with a 1.60 exh valve.
Posted By: R/T1968R/T
Re: 915 and 516 CC's - 04/07/14 06:26 PM
Measured an NOS set of 915s and they measured 79ccs with new valves. 516s are usally about 83-84ccs
Posted By: JohnRR
Re: 915 and 516 CC's - 04/07/14 07:34 PM
Quote:
Measured an NOS set of 915s and they measured 79ccs with new valves.
Then you got lucky , 2 sets I have were both over 80 and I know one set was cut at least .015
Posted By: Goat330
Re: 915 and 516 CC's - 04/07/14 07:42 PM
Quote:Quote:Quote:
915's run about 84cc if I measured right , 516 ??? Do NOT use NHRA specs, they are smaller than actual.
I though they were like 78
That's the NHRA spec and it is WRONG
NHRA spec for 906 is 79.5 cc ... WRONG
NHRA spec. has nothing to do with actual chamber volume on a stock head. It's the volume that you have to follow to build a legal stock class racer.If you're under their spec in CCs,then your car would be illegal.
Posted By: JohnRR
Re: 915 and 516 CC's - 04/07/14 11:31 PM
Quote:Quote:Quote:Quote:
915's run about 84cc if I measured right , 516 ??? Do NOT use NHRA specs, they are smaller than actual.
I though they were like 78
That's the NHRA spec and it is WRONG
NHRA spec for 906 is 79.5 cc ... WRONG
NHRA spec. has nothing to do with actual chamber volume on a stock head. It's the volume that you have to follow to build a legal stock class racer.If you're under their spec in CCs,then your car would be illegal.
Huh ???
NHRA spec , which I'm told is given to NHRA by Chrysler says that the combustion chamber volume of the 906 head is 79.5 cc , 906's out the door from Chrysler typically are 90 cc, I have had more than 1 pr at 92 cc ...
The op asked for 915/ 516 chamber , I have had 2 sets of 915's , neither were below 82cc, NHRA spec is lower than that.
Posted By: BSB67
Re: 915 and 516 CC's - 04/07/14 11:54 PM
I have 2 sets of 915s. They are 79 and 80.
Posted By: BSB67
Re: 915 and 516 CC's - 04/07/14 11:57 PM
Quote:
They typically measure out to 84cc, just like the Edelbrocks with a similar chamber.
R.
The chambers are really not that similar.
Posted By: JohnRR
Re: 915 and 516 CC's - 04/08/14 07:17 AM
Quote:
I have 2 sets of 915s. They are 79 and 80.
Do you know if they have been cut ?
Posted By: BSB67
Re: 915 and 516 CC's - 04/08/14 12:46 PM
Both sets are now cut. Thoses were measured originals. Since then, one has had a valve job and cleanup cut and the other new valves and a cleanup cut. Cuts were about 0.010". They now measure 77 and 78.
Posted By: JohnRR
Re: 915 and 516 CC's - 04/08/14 05:43 PM
Quote:
Both sets are now cut. Thoses were measured originals. Since then, one has had a valve job and cleanup cut and the other new valves and a cleanup cut. Cuts were about 0.010". They now measure 77 and 78.
Interesting .
Anyone know what ACTUAL piston to deck is on a 67 440 ? I'd like to do some math to determine actual compression ratio vs. claimed.
And no NHRA spec Deck to piston is not correct .
Posted By: titan
Re: 915 and 516 CC's - 04/08/14 06:36 PM
Well I Just Rebuilt A Pair of '67 516's of of an never apart 383. new stainless valves,(1.74 Exhaust) & cut.010, and they measure out at 73cc
Posted By: JohnRR
Re: 915 and 516 CC's - 04/08/14 06:53 PM
Quote:
Well I Just Rebuilt A Pair of '67 516's of of an never apart 383. new stainless valves,(1.74 Exhaust) & cut.010, and they measure out at 73cc
I just checked NHRA tech specs , 915 and 516 they are calling for 73.5 minimum CC .
Your heads are not legal now after .010 removal
Posted By: BSB67
Re: 915 and 516 CC's - 04/09/14 12:55 AM
Quote:Quote:
Both sets are now cut. Thoses were measured originals. Since then, one has had a valve job and cleanup cut and the other new valves and a cleanup cut. Cuts were about 0.010". They now measure 77 and 78.
Interesting .
Anyone know what ACTUAL piston to deck is on a 67 440 ? I'd like to do some math to determine actual compression ratio vs. claimed.
And no NHRA spec Deck to piston is not correct .
Piston CH is 2.002"
Distance below deck ranged from 0.073" to 0.086" Driver's side averaged 0.085", passenger side averaged 0.075". #2 rod was 0.003" longer than the rest. My notes say that the head gasket measured 0.022".
I just measured the lower cylinder bolt flange thickness: 0.989". So if you believe that it was 1.000" from the factory, it apprears I had 0.011" cut off, verses my estimate of 0.010".
As I think I have mentioned in the past, a decent rule of thumb is 2.00", 2.03", and 2.06" for 67, 68 and 6 pack pistons. They were about 0.080", 0.050", 0.020" below an uncut deck respectively.
Remember, a valve job will add 1 or 2cc to the chamber volume. A hack job could add 3 cc.
Posted By: GTX MATT
Re: 915 and 516 CC's - 04/09/14 12:59 AM
Quote:Quote:Quote:
Both sets are now cut. Thoses were measured originals. Since then, one has had a valve job and cleanup cut and the other new valves and a cleanup cut. Cuts were about 0.010". They now measure 77 and 78.
Interesting .
Anyone know what ACTUAL piston to deck is on a 67 440 ? I'd like to do some math to determine actual compression ratio vs. claimed.
And no NHRA spec Deck to piston is not correct .
Piston CH is 2.002"
Distance below deck ranged from 0.073" to 0.086" Driver's side averaged 0.085", passenger side averaged 0.075". #2 rod was 0.003" longer than the rest. My notes say that the head gasket measured 0.022".
I just measured the lower cylinder bolt flange thickness: 0.989". So if you believe that it was 1.000" from the factory, it apprears I had 0.011" cut off, verses my estimate of 0.010".
As I think I have mentioned in the past, a decent rule of thumb is 2.00", 2.03", and 2.06" for 67, 68 and 6 pack pistons. They were about 0.080", 0.050", 0.020" below an uncut deck respectively.
Remember, a valve job will add 1 or 2cc to the chamber volume. A hack job could add 3 cc.
Good info
Posted By: Sport440
Re: 915 and 516 CC's - 04/09/14 03:53 AM
Quote:Quote:Quote:Quote:
Remember, a valve job will add 1 or 2cc to the chamber volume. A hack job could add 3 cc.
Good info
Except for that part. I dont see a Valve job adding that much CC per cylinder. Totaled up maybe.
Your typical valve reliefs will add about 3cc to 5cc and the divots will look huge.
Touching the seats and the valves should add very little on a typical valve job. Maybe .2cc max probably less.
Posted By: BSB67
Re: 915 and 516 CC's - 04/09/14 04:11 AM
How much do you think the seat and valve combined are ground on a wore out set of heads?
Posted By: Sport440
Re: 915 and 516 CC's - 04/09/14 04:55 AM
Quote:
How much do you think the seat and valve combined are ground on a wore out set of heads?
Not "Wore out", Just a valve job like you stated.
Back at you. How much do you think the seat and the valve combined are ground on Just a valve job?
Between the two, if its just a valve job as little as .010 maybe .020 if its surfaces are worn.
Not anywhere close to the .250 x.980 sloped .000 to .250 x 4.08 divot combined surface area of my valve reliefs that equates to 5cc in my KB 237,s
Valve job = touch the seat and the valve. .2cc
Valve reliefs = Big .250 x .980 x 4.08 Slanted gutter. 5cc
Posted By: elmor353
Re: 915 and 516 CC's - 04/09/14 07:12 AM
My 67 440 has never been decked and I'm getting .065 -.070 on all cylinders.
Posted By: BSB67
Re: 915 and 516 CC's - 04/09/14 12:34 PM
One of us is doing the math wrong. I too would guess 0.010" to 0.020"
0.020" drop of both valves is almost 2 cc. If my math is wrong, please let me know.
Surface area of the entire valve verses the notch is not a good comparison.
My point is that if someone is getting 84 cc on a set of 915s, it might be be that it has had one or two NAPA valve grinds. Maybe just factory variability...I don't know
0.020" drop of both valves is almost 2 cc. If my math is wrong, please let me know.
Surface area of the entire valve verses the notch is not a good comparison.
My point is that if someone is getting 84 cc on a set of 915s, it might be be that it has had one or two NAPA valve grinds. Maybe just factory variability...I don't know
Posted By: Skeptic
Re: 915 and 516 CC's - 04/09/14 03:53 PM
Quote:The sets I've measured were between 80-82 cc
Can anyone tell me how many cc's the combustion chambers are on these heads?
Posted By: Sport440
Re: 915 and 516 CC's - 04/09/14 05:50 PM
Quote:
One of us is doing the math wrong. I too would guess 0.010" to 0.020"
0.020" drop of both valves is almost 2 cc. If my math is wrong, please let me know.
No your Math is correct, decided to check it myself instead of guesstimate.
At 0.010 on both a 2.14 and 1.81 valve = 1.011 cc
At 0.020 on both double that = 2.022 cc
My eyeball measurement wasnt very correct
Thanks for the correction
Posted By: BSB67
Re: 915 and 516 CC's - 04/09/14 11:53 PM
I used 2.08 and 1.74 as we are talking about factory heads so my numbers are a bit less. I too was a little surprised at the magnitude of the volume change with small changes in the valve depth.