Cyl heads.

If you need to get into the heads my personal experience on a stockish 383 is 452's are better than 516's. All else the same more power based on tire spin. CR diff is not that great but flow advantage for 452's is. Lot of good info on moparts tech archive on all this.
1.74 exh valve in 516 takes care to not make worse.
 
furious70 said:
If you need to get into the heads my personal experience on a stockish 383 is 452's are better than 516's. All else the same more power based on tire spin. CR diff is not that great but flow advantage for 452's is. Lot of good info on moparts tech archive on all this.
1.74 exh valve in 516 takes care to not make worse.
Click to expand...
I would agree on a 393-2 bbl, of course then the compression would be down in the 7.5:1.
His car is a 383 HP and as you can see from the good cylinders is not shabby and with the closed chambers, steel shim gaskets and high compression height pistons makes for decent quench and anti detonation turbulence from the 516 heads. The car is on exhaust manifolds so exhaust flow is already compromised so hurting flow is probably not going to happen as long as bowl is back cut. He is most likely not going to change all the valves to ones without the lips like stock valves so another blow to low speed low lift flow.
The 452 heads are good but the increase in flow vs loss of that much compression on a small bore short stroke is a definite downgrade. His cylinder pressure on the "good" cylinders is at a perfect level dropping that down around 25psi will be a negative in throttle response feel, just for marginal exhaust port flow gains.
If he was changing the cam to a dual pattern and going to install headers and do a very good valve job with better valves sure. That's not Will. IMO. That's why I suggest redoing the current heads.
 
a 383HP with 516 heads on it, what is that?
Let's be honest - 516/915 heads are not really closed chamber, they are 'more closed' but 516's still often have a volume of 78-84cc's. I have one set cut quite a lot and they are still 74cc.
.020 gaskets can go back on with either of the heads, there's no difference there.
You can mess up the 516 with a 1.74 exh, I have a set of those as well. You can also do it correctly as fast68 shows.

Lot's of info from fast68 here -
Moparts on the Web - Main Index

best bet for a street engine would be a set of 906's hands down, if you need an OEM head. I had the back to back 452/516 comparo on the same engine in the same car and saw improvement, you'd see a big improvement with the 906 or any head modeled after it.
 
bluefury361 said:
I found the app Stan. Just have no clue how to get it on my smartphone.
WiFi endoscope HD720P

Model YPC99-5
app is inskam
Click to expand...
OK.
Step one: Do you know how to use the Google Playstore app on your fone?
Everybody else: Shut the f#@& up.
I'm gonna show you how to troubleshoot which is a lost art.
 
commando1 said:
OK.
Step one: Do you know how to use the Google Playstore app on your fone?
Everybody else: Shut the f#@& up.
I'm gonna show you how to troubleshoot which is a lost art.
Click to expand...
C'mon, I was gonna tell him it's the ballast resistor...

BTW, a heads up... mine works through the WiFi rather than bluetooth. That drove me nuts.
 
Y'all should have just suggested to borrow the borescope from O'Reilley's or AutoZone for free to have a look in there.
And I'm trying to save the man from wasting money rebuilding 516's.
 
commando1 said:
Stop bench racing and just help him fix the problem. :poke: :rofl:
Click to expand...
I did #1 is charging number 7 I'm just not sure which valve, but guessing the intake. Hard to believe though that it's not coughing every time the throttle moves.
I also suggested that he just do the 516 castings on his car already because they are correct looking and it has nice cylinder pressure for great throttle response. Will is no longer a hotrodder so improvements by chasing down unknown heads that also need a valve job is IMO not worth the effort. If he had a set of heads from a engine he knew history on or had personal relationship with P.O. and they were a bolt on (no work needed), then sure. I would never bolt a set on with no personal history that some D.B. said they were good without checking them myself first.
The camera will tell you if there is damage to piston (maybe), and we pretty much know there is not a hole in #1 because the blowby and oil consumption to and from New Orleans would have given it away.
 
commando1 said:
OK.
Step one: Do you know how to use the Google Playstore app on your fone?
Everybody else: Shut the f#@& up.
I'm gonna show you how to troubleshoot which is a lost art.
Click to expand...

I know what it is Stan, I found the app there. I made a couple attempts to download it but don't see in my list of apps on the phone.
 
furious70 said:
Y'all should have just suggested to borrow the borescope from O'Reilley's or AutoZone for free to have a look in there.
And I'm trying to save the man from wasting money rebuilding 516's.
Click to expand...

If I do rebuild the heads it will be the originals on the engine. Adding power to the HP 383 is of no interest to me. It pulls the Polara along just fine in it's original form.
 
bluefury361 said:
If I do rebuild the heads it will be the originals on the engine. Adding power to the HP 383 is of no interest to me. It pulls the Polara along just fine in it's original form.
Click to expand...
I cannot relate in any way, but I appreciate the perspective :thumbsup:
Not just performance, but also cost is a factor. You can often spend more rebuilding your original heads than buying someone else's rebuilt/gently used heads, or even new ones these days. Yes, used parts do come with some risk, but for that risk comes the reward of 50-75% discount. If all that sounds like a hassle and 'peace of mind' comes from paying someone to rebuild your heads, then that's what floats your boat.
 
furious70 said:
I cannot relate in any way, but I appreciate the perspective :thumbsup:
Not just performance, but also cost is a factor. You can often spend more rebuilding your original heads than buying someone else's rebuilt/gently used heads, or even new ones these days. Yes, used parts do come with some risk, but for that risk comes the reward of 50-75% discount. If all that sounds like a hassle and 'peace of mind' comes from paying someone to rebuild your heads, then that's what floats your boat.
Click to expand...
I can relate to what your saying and I did buy a set of long, long time ago ported 906 heads. They were freshened up and have okay parts, yes I took them apart and checked them over.
The only reason I even suggested putting a 1.74 valve was to get a seat in virgin iron if it was a exhaust valve problem.
I would not leave it alone, but figured that Will is not looking to go down that path. It has taken me a while to realize that other people don't want to wind everything up tight.
 
bluefury361 said:
I know what it is Stan, I found the app there. I made a couple attempts to download it but don't see in my list of apps on the phone.
Click to expand...
Good.
You say the app is on your phone.
First: Has a new icon appeared on your screen?
If yes, pressing on it will open the app.
If no, open your "SETTINGS"
When SETTINGS is opened, you'll see a list of "settings".
Scroll down the list of settings and click on "APPS".
When APPS opens, you'll see, well... a list of apps installed on your phone.
Scroll down to the name of your app and click on it.
The apps info will come up and press on "OPEN".

We'll stop here until you confirm.
 
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