Head Gasket info

It's been 12 years since I built my 428.. Notes, some specs, and my service manual with detailed notes has since left my known possessions.I messed up on my math and instead of having 12.5 to 1 ended up with 13.22 to 1 compression.
If memory is serving I have the felpro high performance head gasket on at least one side of the block possibly match on the left... Might have done a driver side head gasket at the strip between passes last time I ran it.
I'm looking to start getting back into my toy but would prefer pump gas and I'm not keen on aluminum heads just yet money being the major factor.
I was wondering if anyone knew the thickness of the felpro 8518pt or the victor reinz equivalent for the stock head gaskets.
I have 2 sets of #62 casting heads and both were milled .030 .
I am looking at cometic head gaskets to solve temporarily the compression issue.
Great to be able to drive the car after 12 years and another to teach my ten year old how to start working on it... Being he would like to use it eventually.
Anyone got those specs would be greatly appreciated.  
Viagra and Torque are one in the same they both get you up!

Pontiac_Iron

I have gotten 2 different thinkness numbers.

.039 and .040. Just maesure it when you get yours apart. Its a multi layer perma torque head gasket..

Bob  

Pontiac_Iron

If you have any thoughts I would take the time and replace them both... Be safe, not sorry.

Bob  

Oh I had intentions on doing them both...
Not sure if I had since. The cars been off the road for 12yrs.
I just can't recall if I ever changed them after the track last time I ran it.

I plan on re doing A LOT!

gonna change out the cam as well. Engine is still new. Don't think o put 2k in mileage on it.
I put the car back together after my 455 imploded.
Had some more fun but wife, kids, life made some needed changes and I garaged the car for the better part of a decade... Couldn't part with it.
And I like Pontiac torque over chevy everyday.
The new PHR engine contest bothers me at what avg numbers the lone pontiac engine is producing comparatively speaking...
I know the pontiac if built right can do far better than those numbers.

But I plan on getting things straight... Right now trying to map out how to get back to pump gas without shelling out 4k in aluminum heads and that much more in head work which has probably gone up in price since I last had some done.  
Viagra and Torque are one in the same they both get you up!

If you have 13:1cr you will need to change more then just head gaskets to run premium pump gas.  
Engine builder,self taught auto body guy.
Horsepower sells engines and torque wins races

I think I can get close if not on the mark where I would be Comfy just over 12:1 using cometic head gaskets.
I milled 72cc heads .030... Making them 66cc.. mistake years ago and eager to smoke my friends on the street and strip... Shortsightedness.

Rose colored glasses are off and superhigh octane not where I wanna be nor at the dragstrip anymore.

I was thinking about .050/.060 cometic head gaskets to get me under the 100 octane + mark.
It can't hurt to try before shelling out 4k on aluminum heads.
I was just trying to figure out if the performance head gaskets were thinner than stock or around the same thickness.
Felpro lists the specs for the performance but couldn't find stock if it were different to start crunching numbers and try to correct poor mathematics all those years ago. I wasn't big into computers nor did I have software at my disposal to crunch the numbers...
Let's just say I was way off the mark 2x's with the same casting for different reasons... But my compression calculation is spot on this time and I shake my head at how slow on the uptake I was back then when I did it.
Hindsight normally 20/20... I'm scratching my head at myself!
LoL.  
Viagra and Torque are one in the same they both get you up!

If you are wanting to run pump gas you will need to get the CR down to 9.5:1 maximum,Especially on today's pump gas.  
Engine builder,self taught auto body guy.
Horsepower sells engines and torque wins races

I think if o can get to 12:1 93/94 octane will suffice. Not much different than todays corvettes.
I can always use lead substitute or something of octane boost to squeak by... Never a big fan of the stuff but I know a couple do work alright.  
Viagra and Torque are one in the same they both get you up!

There is an option to keep the compression if E-85 is available by you.  

Issues that I have read about for E85 is it will if used enough start to deteriorate even forged pistons.
How true that is I don't know. But that was the consensus of the articles I have read.
I know I will probably be buying aluminum heads In the future.. my past mistakes of milling heads has left me in my current state.  
Viagra and Torque are one in the same they both get you up!

I'll consider moonshine.
Shot for the car shot for me one for the car one designated driver for me.  
Viagra and Torque are one in the same they both get you up!

Pontiac_Iron:
I think if o can get to 12:1 93/94 octane will suffice. Not much different than todays corvettes.
I can always use lead substitute or something of octane boost to squeak by... Never a big fan of the stuff but I know a couple do work alright.

I very much doubt that.
One should never compare a chevy to a Pontiac engine, two totally different engines.

All the band aids in the world will not fix a too high of compression for the octane being used problem.

You would have a hard time running pump gas and 12:1CR even with aluminum heads.

Detonation will occur and then damage will follow.  
Engine builder,self taught auto body guy.
Horsepower sells engines and torque wins races

cool lookin 69! how in the world did you come up with 13to1?  my chart shows 11.35 on a .060 428 at 66cc. #62 head are listed as 75cc. unless you 0 decked the block or used dome pistons, longer rods or stroked the crank. i must be missing something!

i had a .030 455 with 72cc #48 heads at around 11to1 and had to run no less than 100 octane gas.

just put some 86 to 96cc  heads on it. i now have a .030 455 with 7k3s 9to1 and can run the 87 octane but it likes the 91 better.  
76 455/4spd TRANS AM
69 GRAND PRIX 406/5SPD

Pontiac_Iron:
I think if o can get to 12:1 93/94 octane will suffice. Not much different than todays corvettes.
I can always use lead substitute or something of octane boost to squeak by... Never a big fan of the stuff but I know a couple do work alright.

Pontiacman8:
I very much doubt that.
One should never compare a chevy to a Pontiac engine, two totally different engines.

All the band aids in the world will not fix a too high of compression for the octane being used problem.

You would have a hard time running pump gas and 12:1CR even with aluminum heads.

Detonation will occur and then damage will follow.

+1 Pman
Sounds like a recipe for disaster, in the making.
Aluminum heads, with fast burn chambers and on-board electronics, will not tolerate compression of 12 to 1, on today's pump gas.
VP Racing Fuel has C12, that might do the trick.

SPECIFICATION SHEET FOR C-12

(Typical Values) Specific Gravity: .717 @ 60F

Lead: Yes

Color: Green

Motor Octane: 108

Reid Vapor Pressure: 7.3

Oxidation Stability (min.) 1440+

Distillation:
10% evap @131.0°F

50% evap @194.0°F

90% evap @228.0°F

E.P. @233.3°F

Production: Elmendorf, Texas USA

Availability: Sealed Drums

www.vpracingfuels.com/c-12-spec.html

 
When The Flag Drops,,,



The Bull Chit Stops,,,


P. Engineer, Engine Builder

Thanks. The car needs a lot of work again... I let it sit for over a decade... Time to start over again.

The heads #62 casting were 72cc chambers stock..
The formula I based on and to my recollection was for every .010 milled off the head you trim 2cc's.
So I milled .030 off to beef up the compression. I did this to two sets of the same casting... Again hindsight I wouldve done different things.
But I was young and hot to trot on the street and strip.
Milling .030 off if what I recall is accurate would give me 66cc's
I didn't touch the block other than .030 over bore.
The formula I used had me use numerous factors I didn't take into consideration 12years ago..
But the number it spit out was 13.22.
I can't after reading what you wrote confirm 100% but its got pre-det with 93 so its up their and as tough as the stock starters are its a good challenge for it. It is a fairly new starter.. battery is gel cell with plenty cold cranking amps.
I don't think putting .050 or .060 is a band aid. It's a solution... And cometic gaskets are top notch.. so it seemed like somethin to try before I shell out money I can allocate to the rest of the car at this time.
I know 12:1 can or could if I'm wrong now... But could run 93/94 octane.
The engine loves 100 up octane..
The car is streetable... But it used to cost 200.00 on a cruise night to drive... 6-8 mpg less once once the secondaries open up. It drinks... I usually would run 5psi on street boost it to 7psi at the strip or some fool looking fo put his money where his mouth was.  
Viagra and Torque are one in the same they both get you up!