Glad to hear you're working it all out.
I went through that manifold oil leak on another engine. I experienced a heavy oil smell after a WOT blast or two. It smelled more like oil getting burned on something hot rather than what you get out of the tailpipe. Sure enough, it found it's way onto the exhaust. I had always tended to be skimpy on the RTV between the block and manifold until I went through what you've described. I hope to never make that mistake again.
What's more, that same manifold, which is Victor Jr on a ZZZ block, also leaked at the intake runner. Pulled oil into the cylinder head. That was a tough one to figure out.
I'd like to see the results of your compression test. Keep us posted.

 

Just a little update,

Oil Leak: I figured out the vortec distributor hold-down bolt hole wasn't lining up with the Stealth Ram bolt hole. It was pulling the hold-down from off of the distributor when I tightened the bold down. I bored the hole out more and it sealed the leak. I talked with EFI Connections, they told me to go back to the original tpi distributor clamp, either way it's fixed for now.

I haven't got a chance to do a leak down test yet but I did make it out to the track for some quarter mile runs. The car (without me) weighed in at 3524 lbs. First pass NA it ran a 12.55 @ 111 mph with a 2.0 60 foot.

Second pass I was up against a 03 SVT Cobra, whose owner was real snotty so I decided to run the spray. Unfortunately it cut out really bad due to it being 55 degrees and I didn't have the bottle heater hooked up yet. Ran the exact same time, and lost to the Mudstain.

Third pass I ran NA, and decided to launch it a little harder. Pulled a 1.8 60 foot and managed a 12.50 @ 112mph.

The AFR read between 12.4-12.7 on all runs. I think it will actually run a little better at around 12.1-12.4, so I will give that a try next time out.

I think she has some 11 second NA runs in her with some weight reduction, additional tuning and once it is fully broke in.

It should be real interesting on the 200-250 shot.

 

Performance (and weight)are very similar to my own so certainly you have more in it. More power (I would think with 383 vs 355) and better gearing say so anyway.
As for AFRs, don't you think getting less the 12.5:1 is getting a little rich? That's where I'm at presently and my thinking is better results with something closer to 13:1. That said, there are too many variables to be able to compare yours to mine but I figured it's worth mentioning.
With that trap speed, I would think that 11's are totally within reach. I've pulled a 1.71 60' and that's also a very reachable target. Mine has dropped off significantly over the years (tires perhaps? More torque, less traction?) and to get back another 2/10ths in the 60' has shown to be worth 3 to 4 tenths at the top end.

Still waiting on your compression test results....

 

Thanks for keeping up with my post Skinny!

The crazy thing is my 1/8 mile times were the same MPH as I ran with the factory l98 short block. (86mph) I had 3.73's then (instead of 4.11s) but I wouldn't think it would make that big of a difference.

I have read that the e10 gasoline we run brings the ideal AFR down a bit, it seams to pull a little harder at the lower AFR ratios, I have run it around 13.0 and it seams to not pull so hard. Of course I know the butt dyno lies. A dyno tune might be the next step.

I'll get around to that compression test soon enough. Any recommendations? I don't have any tools and was going to try to rent one somewhere, or pick up the Harbor Freight deal? Leakdown or just compression test?

 

We found (or rather one of my circle track engine guys found) that the 10% ethanol based fuels produced less power on the dyno than the pure gasoline counterparts. The ethanol blend has 3 points higher octane rating however these Vortec based racing engines ran about 9:1 compression. The added detonation resistance wasn't needed.
As for AFR, with all of the variables, such as location of the O2 sensor or even the brand of gauge, will skew the results from one vehicle to the next. You're right in that a trip to the dyno is the best way to nail it down. Certainly more convenient than swapping jets at the track all day and dealing with changing weather and track conditions.

I prefer the screw in type compression tester. I have an inexpensive version from our Harbour Freight equivalent but it appears to be a solid piece and has held up well (and predictably) over the years I've owned it. The leak tester I use more for in depth diagnosis. If I find the cranking compression is off significantly from I've pre-calculated it to be, then a leak down test is performed.

 

Just an update

Spent a few hours trying to test my cranking pressure. I bought the quick connect Harbor Freight tester. It was very slow to build up pressure (15 seconds or more of cranking) and only got to about 90. I started freaking out so I tested number 3, same exact thing. I put all the plugs in and warmed the engine up more to see if it wasn't warm enough. No dice same thing.

I then decided to run up to Autozone and rent one of theirs. Cylinder 1 just a hair under 160 (159), cylinder 3 155. I couldn't get the connector to clear the headers on 5 and 7. Cylinder 2 was the only other one I could squeeze on the passenger side tested at about 155.

I ran it through the Wallace Racing compression ratio calculator and it looks like my final dcr is between 7.80 to 7.95, with a SCR between 10.2 and 10.4. Looks like I am right in line with what I was calculating it to be.

I will try to find an adapter or something to get readings on the back cylinders.

 

Nice to see the updates.
If you can (rather than re-reading your posts) what are your engine specs?

 

Vortec 880 4 bolt block bored 30 over, line bored, cnc clearanced, ARP main bolts, decked (measured .019 to .021 at lowest) Felpro .015 copper gasket.
383 Scat 9000 cast crank
Scat Pro Series I-beams (7/16 ARP bolts)
Weisco Pro Tru Street forged pistons PTS534A3 reverse dome -20cc, JE Pro Seal rings gapped for nitrous
Comp Cams 280xfi, LS7 lifters, comp 5/16 magnum pushrods, comp 918 beehives/retainers/locks, on GM vortec heads.
Stealthram 58mm valvebody, 30 lb for red injectors
411 PCM swap

 

It'll be a while but I'll do a little reverse engineering on this. It's always interesting to see "cause and effect".

 

Tell me more. In 1988, I bought the nitrided steel SBC 5140 crank and hi-nickel 4 bolt main block from the GM Performance Parts catalog for a 350 I put together. I still have it. Back then, that was nearly the best you could get, unless you wanted to spend $2000+ on a billet crank.
12.5:1 compression, ran for 1 summer on the street. Not like Street Outlaws today. Shifted at 8200 rpm. Carrillo rods.
Solid flat-tappet camshaft.

 

Using these values:
4.03 x 3.75
63 cc heads
.015 x 4.100 gasket
.020" deck
20 cc dish
5.7 rods
280/288, 113 LSA, 109 ICL

10:1 SCR, 7.76:1 DCR

Theoretical cranking compression (with 10:1 SCR and the cam installed on a 109 ICL) at 147 metres above sea level is 186 psi. That's what my 10:1 / 8:1 Vortec 350 had.
9.5:1 yields 174 psi. I've found the cranking pressure numbers to be pretty close in general but there are always other contributing factors. (I checked the elevation of Irving, Texas). When I moved across the country from 70 metres above sea level to 700 metres I lost over 10 psi.
Anyway, that's just theory. And perhaps my lousy math...

 

Here is what I got: SCR - 9.66, DCR - 7.52, 150.73 PSI
using 14.7 for atmospheric pressure, and assuming
a top ring height of .200" down
and a ring land to cyl bore clearance of .005".

 

Compensating for your altitude of 147 meters:
9.66, 7.52, 148.17

 

Notation should have been irocman7 383, not skinny z 383.

 

Elevation 480 feet, forgot to mention 6 inch rod.

 

Seeing No E's results made me go back and look at my own. I couldn't see how the crevice volume could amount to much of a difference as it's less than .2 cc.
Turns out I had entered an incorrect value for the gasket bore. Now I end up with 9.66 and 7.52. Makes sense.
Taking into account the 6 inch rods and the DCR drops to 7.49.
The cranking compression with the revised altitude (which is a sketchy proposition at best as it's as much weather related as it is altitude) and longer rod works out to a theoretical 177 PSI.
Somewhere between the two pressure calculations lies the truth. Thing is about a compression test is that there are just too many variables to make any conclusions (as in real results vs calculated results). The only real value is when comparing two engines that are tested under the same circumstances with the same equipment. I've always found a reasonable correlation between the theoretical and the actual when it's approached that way. In my case, it's the same test equipment, engine cranking speed (a big factor there), same method, etc. At one time I had started to assemble a data base using other peoples real test results and comparing to the calculated value. It wasn't too far off but hardly scientific or reliable.
All of that said, with your reported cranking pressure and the results from SCR and DCR calculations, you should have plenty of tolerance to detonation and easily be able to absorb and healthy spark advance curve. The ignition timing I've found has a far greater impact on engine performance than does the compression ratio. Pulling timing out of engine to save it from spark knock kills performance and efficiency.
Now that's not a blanket statement but one that reflects what I've experienced under the conditions that I see on regular basis.

 

Verified. 9.66, 7.48, 147.81

 

Real life testing has shown the theoretical 147 psi cranking pressure to be a little low.
Both with my personal tests and that of the OP.

 

Something's not adding up, I think there's another variable that's not being factored in. I used the online SCR calculator and came up with the same values as ya'll did. I think there's a dimension of the piston that is not being factored in the calculator, or the 20cc number is not what we think it is. They use the word "volume".

Wisesco rates these as 9.9 to 1 with a 64 cc chamber. I asked them about this and they stated this is factoring in a .020 deck height, which is exactly where I am at. Also considering I milled my heads down to about 63 cc combustion chamber I should be a little over 10.1 (which falls in line with the cranking compression).

Here are the specs they list for the piston
PTS534a3 piston

Compression height: 1.125
Volume: -20 cc
Stroke 3.75
Rod: 6 inch
Compression ratio at 64cc: 9.9 to 1

I just sent them another email for clarification.

 

Try the SCR calculation but enter a zero deck as opposed to .020" down. That might bring the ratio up to 9.99.
(I don't have access to my PC to run them myself).

 

I tried that earlier and it does bring it up to 10.1, but that's with a .015 gasket (.015 quench), .035 gasket brings it right back where we started.

 

Well hell, just got the response back from Wiseco....

Email:
Hi Preston,
I have also run the numbers you are providing and I am also coming up with 9.6:1 compression ratio. We have a boo boo in our catalog on the numbers for this piston and it should actually read 9.3:1.

We appreciate that you have brought this to our attention and will make sure it gets fixed for 2018.

I am trying to talk them into a discount for my 496 build.

Good work TGO motor nerds!

I do have the possibility of buying a vortec supercharger, maybe I should throw that thing on there...

 

Thanks Wiseco...for nothing.
And thanks to NoE for pointing out the correct calculated value. It got me to thinking and rechecking my work. I'm curious as where the error is. It has to be in the dish volume if they calculate using a zero deck.
A fella could get pretty steamed over something like this. Interestingly though, I've never purchased a piston that was advertised as "X" compression ratio. Give me the valve relief, dish or dome volume and I'll figure out what the SCR is.
That said, I hope you get some kind of restitution from them. It would seem fair.

 

Yeah, that sucks.
On the plus side, you did run a 12.5 sec quarter mile.
Not too shabby.

 

It's not that big of a deal, these pistons are nice pieces, and I ended up getting them really cheap. I knew there was a risk of not getting the compression I wanted, with them being listed as 20cc dish.

The customer service from CNC-motorsports and Wiseco has been wonderful. I am going to use Wisecos on my big block build.

If you remember originally I decided to go with the 9.5 Icon pistons, they were out of stock so they moved me to the Wisecos. So really I ended up about where I was.

The way I figured I am out at the most about 16 hp, and now I can run 87 octane.

I think this motor will end up clicking some 11's on the motor, and maybe some 10's on the spray, so it will be fun.

 

That's a very good example of Hobo Fake quality. I will no longer use any HF tool that requires calibration for accuracy. I keep snapping off 1/4x20 bolts with my HF torque wrench before I found it way off cal. That and a fuel pressure gauge that would stick at mid-range right where I tried to read it.

I think you now see the value of taking your own piston volume measurements while at TDC. Can't get fooled with your own measurements. I see you measured the heads so you know how to do this. Piston creavase volume is less than 1 cc but can't be ignored. I used to ignore creavase volume myself but have been corrected to see the significance now.

Well congrats on a nice build. I expect you will find that somewhat lower compression motor will take a huge amount of abuse.

Have fun and let us read 'bout your BB build to.