516 cyl head project

Rob R

Rob R

Well-known member
I've been playing with these 516 closed chamber cyl heads and I'm pretty sure there going to go over 280 CFM(2.14/1.81)...there's way too much time in them to make it worth while for the average guy to pay someone to do this to a set.
Just buy a set of EZ's or Edelbrock and get the same for 1/2 of what it would cost to do something like this...
But it was a nice little project and I'm happy with the way they are turning out...I'll go give them a pressure test and then a nice full radius valve job and a quick back cut on the valves...and toss them on the flow bench and see what they pull...
516new.jpg

516new2.jpg
 
Ooooooooo, Ahhhhhhhhh.......that's some serious amount of work. :clap:

Will be interesting to see the bench results.:)
 
That's some serious reworking for 516s Rob. Was this on a bet or something you wanted to try to do for a while?
 
6pkrunner said:
Was this on a bet or something you wanted to try to do for a while?
Click to expand...

:bwuhaha: almost...

I had another set of these from last year that I was selling...I figured I'd do a little more to those because I saw a couple of spots that could use some improvements(so I touched them up)...and when I check them they were 274 cfm...
anyway when they were on the bench a customer was watching the whole procedure and asked if they were for sale...he bought them on the spot...he also asked if there was any more left in them...long story short...282 cfm
Now back to these 516's...someone had expressed interest in the last set and I didn't want to have come across as selling them out from under him so I figured I'd do up another set...HOW LONG COULD IT TAKE..:huh: ...well I forgot how much time was in those other heads...as usual my est. was opotomistic to say the least :rolleyes:
so in for a penny in for a pound and it was something that I had to see if I could do again...
one thing is for sure...NEVER AGAIN...unless someone is going to pay for all these hours..
these will be nice once I'm finished...after I cut the seats I'll won't look at them for a couple of weeks and come back fresh and really pretty them up...
I find with iron heads I have to step away for a while because every time I come back to them there's something that I can't believe I left (as in what a mess)
here's the first set..

closed.jpg

closed1.jpg

closed2.jpg
 
Very nice indeed.

You mentioned getting another 8 cfm out of a pair,

It's kind of a loaded question, because once your heads breathe you can change other stuff, but what is the effect of cfm on HP? Yanno, like 10 cfm on a 440 will get you xx HP.
 
Rob R said:
:bwuhaha: almost...

I had another set of these from last year that I was selling...I figured I'd do a little more to those because I saw a couple of spots that could use some improvements(so I touched them up)...and when I check them they were 274 cfm...
anyway when they were on the bench a customer was watching the whole procedure and asked if they were for sale...he bought them on the spot...he also asked if there was any more left in them...long story short...282 cfm
Now back to these 516's...someone had expressed interest in the last set and I didn't want to have come across as selling them out from under him so I figured I'd do up another set...HOW LONG COULD IT TAKE..:huh: ...well I forgot how much time was in those other heads...as usual my est. was opotomistic to say the least :rolleyes:
so in for a penny in for a pound and it was something that I had to see if I could do again...
one thing is for sure...NEVER AGAIN...unless someone is going to pay for all these hours..
these will be nice once I'm finished...after I cut the seats I'll won't look at them for a couple of weeks and come back fresh and really pretty them up...
I find with iron heads I have to step away for a while because every time I come back to them there's something that I can't believe I left (as in what a mess)
here's the first set..

closed.jpg

closed1.jpg

closed2.jpg
Click to expand...

ROB , they really look great :bravo:
 
Thanks guys...there not finished yet...they need a bit more love...chambers have to be finished ..cross sections...lots of little things.
way too much work for the return :(
they still should light the tires all through second gear:)
 
Rob, you are the Michelangelo of the iron head. The pride in your workmanship is pretty obvious.
However, I must ask - how much time spent with the cutter? Not the time for the usual work to revive a set of heads, but your time to make the 516s work? From the pictures you posted and trying to recall a set of 516s from a few years ago, the hours have got to be serious.
 
Mike...it sick how long it takes...2+ hours a port plus the chambers plus the time it takes to pretty them up once your close...I can do two sets of 452's for every set of 516's...
My problem is I try and out do the last set I did every time...
If I'm porting an Iron head I'm going to get every last .oz of power out of them or why even bother...
there's only been a couple of times where I only went half way on a set of heads and it's just not worth my time...if I'm not going to be happy with the end result I'm not going to do it...
 
Rob R said:
My problem is I try and out do the last set I did every time...
Click to expand...

Best way to keep your interest up isn't it? To stop at the same place each time you may lose interest.

Now I must inquire once again. When does moving the port(s) and corresponding intake and exhaust modifications begin? Or have you set the quest to go as far as possible with the standard big block layout? Much like where Tom and company were with the Hemi D4/D5/D6 heads in the 70s.
I'm sure that there is a plateau waiting for you and with your abilities I am curious where the next level is for you? As you stated, money cannot buy the effort put into these and the quest for flow is the driving force. When the tunnel closes, where then?
Of course I'm sure no one would ever have expected 516s to go anywhere near 280 cfm. Have you made a pact with someone in a place of power to suspend the laws of pressure differentials, aerodynamics and physics?:D
 
Mike...I wouldn't start moving anything on an Iron head...it's hard enough fixing a break through on a port but to start cutting and adding [smilie=2: ...
I like it when a customers buddies can't believe how fast the car is with stock heads...then I know all that work was worth it...even though the tune up is a really BIG part of it...
I see lots of million dollar motors with all the go fast goodies you can throw at it and they wouldn't pull a weiner off a plate...door to door with a stock headed engine.
then they throw some n2o at it and split a cyl wall with a 150 shot because they couldn't tune a wheelbarrow...
 
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Rob R said:
I see lots of million dollar motors with all the go fast goodies you can throw at it and they wouldn't pull a weiner off a plate.
Click to expand...



reminds me of exactly what Tom Hoover said in an interview many years ago. Something along the lines that he used to go to local tracks and see his beloved hemicars turning mid 14 to mid 15 second quarters due to lack of tuning skills. That was part of his developing the 6 pack induction for the hemi. He said they had a 1968 Coronet R/T as a test mule running the 3 deuces and it was great, but they all saw emissions looming on the horizin and knew the hemi was a dead duck so further development was canned. Funny how that manifold is now available or soon to be available from MP.
But he did lament the lack of tuning skills by owners.
 
BootHead said:
Very nice indeed.

You mentioned getting another 8 cfm out of a pair,

It's kind of a loaded question, because once your heads breathe you can change other stuff, but what is the effect of cfm on HP? Yanno, like 10 cfm on a 440 will get you xx HP.
Click to expand...

BootHead...

Sorry I missed your question...

there's quite a few variables that come into play here...but the short and sweet answer is about a min of 2 hp per CFM ;)
 
Rob, any plans to sonic check the ports after all the work is done ? How did the low & mid lift flow numbers respond with all that work ?


Thanks, Ron
 
Ron...I had the tester in the bowls when I was hoging them out...it's hard to make contact and get a good reading...there was always a band of thin material at the parting line where the two halfs meet...and it was all over the place :eek:
where ever theres a nasty thin spot I'll lay some brass over it to shore up the wall...
these heads are best left alone...the mid numbers on the first set of heads were good... but they started out slow...as soon as I started to open the valve I figured $hit...what a waste...better unshroud it some more and lay back the short side and then it took off...something like 160 @ 200...and then onward and upward...
there's just TOO MUCH WORK for the return
 
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