Hey everyone,
Can someone help me out on how I can tell what's my compression on my rebuilt engine. I asked the guy who built it and he says stock but that doesn't tell me anything.
I have the following.

- Big Block "F" (1969) Bored 0.30 Number: 396021F.
- Heads "C" 80 CCs (1967-1969): 394548.
- Crank Shaft "Nodular Iron" (1968-1970) Number: 397363.
- Speed-Pro Forged Pistons Piston, Forged, Dish, 4.155 in. Bore, 5/64 in., 5/64 in., 3/16 in. Ring Grooves.

I am not sure if there is anything else you need.
Thanks a million.

 

How big is the dish?

What was the deck height?

Were the heads cc'd, or is 80cc just a guess?

How thick are the head gaskets?

How can the guy who built it see his work with his head so far up his a$$?

- Eric

 

You will only get a ball park figure without actual specs. KB pistons has a good calculator.

 

I'd say between 9.1 and 9.2 :1

 

This is what I got on the pistons
Bore (in):4.155 in.
Bore (mm):105.537mm
Piston Styleish, with no valve reliefs
Piston Material:Forged aluminum
Compression Distance (in):1.735 in.
Piston Head Volume (cc):+18.00cc
Wrist Pin Style:Press-fit
Pin Diameter (in):0.980 in.
Piston Ring Thickness:5/64 in. x 5/64 in. x 3/16 in.
Quantity:Sold as a set of 8.
Notes:0.142 inch deep dish design. DurOshield® coated piston skirt.

The gasket doesn't say how thick but its the gasket set that I got. Fel-Pro QKS2613 - Fel-Pro Gasket Kit Sets. Gaskets, Full Set, Oldsmobile, 330, 350, 400, 425, 455

The 80cc is what I got from the 442.com FAQ

 

With .03" deck clearance it should be about 9.3:1 give or take, which is not stock.

 

ASSuming a 0.046" head gasket thickness, 0.020" deck height, and that the 80cc CC volume is accurate, the static CR is 9.4:1.

An original 455 with a 4bbl was 10.25:1, so the compression is not "stock."

- Eric

 

How do you determine these specs so I can do the calculations myself? At summit racing there's a compression calculator (http://www.summitracing.com/popup/ca...ion-calculator)
But I don't understand what most of this stuff means. Does it mater what type of lifter, push rods, cam, etc i have or is it all based on the pistons and cranck shaft?
I am trying to sell my this motor since i no longer have the cutlass and i cant put it in tje 64 impala i bought. It sux because when people ask about the specs I don't know what to say except what I put into it and what the machine shop did.
Anyhow I am on my way to the shop where my motor is at to get more info.

 

Although the 455 was advertised as having 10.25:1, it rarely was, unless it was blue printed. Usually it would come in around 9.9:1.

The only way to find out for sure is to measure everything, unless the engine builder has the measurements for you. I would just advertise it as 9:1 compression.

 

Has anyone ever tried using some benign fluid and filling the cylinder with the piston at the top and the bottom of the stroke and measuring the volumes? Be messy I imagine.

 

After going through all the measurement the compression is 10.8.
Does that seem right?

 

No.
You have between 9.25 and 9.5 by my calculations.

A BBO has a stock deck height of about 10.625-10.630.
If it wasn't decked then let's do the math;

1.735 piston
6.735 rod
2.125 half of the stroke
10.595 Total

Take the 18cc dished piston .030 in the hole, a .046 gasket and 80cc combustion chambers and you get about 9.3:1, just what analog kid said.

And I'll buy anybody lunch if they pull apart a previously unopened "10.25:1" BBO and it really measures 10.25:1. I have yet to do so.

 

That's the way you cc a head - set head upside-down and level, fill combustion chamber with alcohol, gasoline, or something similar, measure amount.

To get it right, use a clear flat piece of plexiglass with a hole in it to cover, to make sure you only add exactly the amount needed to fill, and no more.

- Eric

 

I appreciate everyone's help with this. It's sad when you have to get this info from a forum instead of your mechanic.

So what am I looking at with horse power? 450?

Thanks.

 

Could you be a little more vague?

Cam? Intake? Carb? It might be a 1000, need more info.

 

This is all I put into it.

1. Moroso 20480 - Moroso Street/Strip Oil Pans, Oil Pan, Steel, Clear Zinc, 7 qt., Oldsmobile, V8, 260-455. $252.95
2. Moroso 24460 - Moroso Oil Pump Pickups, Oil Pickup, Bolt-In, Aftermarket Pan Style, Oldsmobile, 260-455. $40.95
3. Melling M-22FHV - Melling High-Volume Oil Pumps, Oil Pump, High-Volume, Oldsmobile, V8. $77.95
4. HASTINGS Moly Piston Rings 2M661-30 +.030 5/64 5/64 3/16 4.155 BORE. US $45.29
5. ARP 185-6001 - ARP High Performance Series Connecting Rod Bolt Kits, Connecting Rod Bolts, High Performance Series, 8740 Chromoly Steel, Oldsmobile, 455, V8, Set of 16. $64.38
6. ARP 100-7101 - ARP High Performance Series Rocker Arm Studs. Rocker Arm Studs, High Performance, 7/16-20 in. Thread, 1.90 in. Effective Stud Length, Kit. $40.08
7. ARP 185-4001 - ARP Pro Series Cylinder Head Stud Kits. Cylinder Head Studs, Pro Series, Hex Head, Oldsmobile, 455, 7/16 in., Stock, Edelbrock RPM Heads, Kit. $119.17
8. COMP Cams 1044-16 - COMP Cams Aluminum Roller Rocker Arms. Rocker Arms, Stud Mount, Full Roller, Aluminum, 1.6 Ratio, Fits 7/16 in. Stud, AMC/Ford/Oldsmobile, Set of 16. $314.95
9. COMP Cams 8704-16 - COMP Cams Hi-Tech Pushrods. Pushrods, Hi-Tech, Chromoly, Heat Treated, 3/8 in. Diameter, 9.950 in. Length, Universal, Set of 16. $166.95
10. Edelbrock 7813 - Edelbrock Performer-Link True Roller Timing Chain Sets. Timing Chain and Gear Set, Performer-Link, Double Roller, Iron/Steel Sprockets, Oldsmobile, V8, Set. $63.95
11. Edelbrock 2152 - Edelbrock Performer-Plus Cam and Lifter Kits. Cam and Lifters, Hydraulic Flat Tappet, Advertised Duration 288/298, Lift .472/.496, Oldsmobile, 400, 425, 455. $184.95
12. Edelbrock 2151 - Edelbrock Performer Intake Manifolds. Intake Manifold, Performer, Dual Plane, Aluminum, Square/Spread Bore Flange, Oldsmobile, 400, 425, 455, Each. $289.95
13. Fel-Pro QKS2613 - Fel-Pro Gasket Kit Sets. Gaskets, Full Set, Oldsmobile, 330, 350, 400, 425, 455, Set. $53.95
14. SFI Flywheel Flexplate?
15. Pioneer Automotive 830011 - Pioneer Automotive Engine Blocks. Expansion Plug Kit. $13.95
16. Clevite Engine Parts CB542P - Clevite P-Series Rod Bearings. Rod Bearing, P Series, Standard Size, Tri Metal, Cadillac, Oldsmobile, V8. $80.95
17. Clevite Engine Parts MS804P - Clevite P-Series Main Bearings. Main Bearings, P Series, 1/2 Groove, Standard Size, Tri Metal, Oldsmobile, 400, 425, 455, Set of 5. $94.95
18. Precision Oil Pumps OLDSMOBILE 350- 455 Billet Oil Pump Drive. CNC machined from 3/8' diameter Billet 4140 Chrome-Moly. $25.00
19. Mr. Gasket 404 - Mr. Gasket Standard Intake Gasket Sets
20. Gaskets, Manifold, Intake, Composite, 2.49 in. x 1.41 in. Port, .060 in. Thick, Oldsmobile, 400/425/455, Set. $17.95
21. R&M Billet Wire Loom 1113R. Ignition Wire Loom/Separator, Horizontal, Aluminum, Polymer, Red/Black, 7-9mm, Oldsmobile, 260-455, Kit. $56.99
22. FlowKooler 1575 - FlowKooler Mechanical Water Pumps. Water Pump, Mechanical, High-Volume, Iron, Natural, Oldsmobile, 350/455, Each. $134.99
23. FlowKooler 330-205 - FlowKooler Robertshaw Series High Performance Thermostats. Thermostat, High-Flow, 205 Degrees F, Copper/Brass, Each. $25.99
24. MSD Ignition 8566 - MSD Pro-Billet Distributors. Distributor, Pro-Billet, Magnetic Trigger, Mechanical Advance, Oldsmobile, 260-455, Each. $281.95
25. MSD Ignition 31189 - MSD 8.5mm Super Conductor Spark Plug Wire Sets. Spark Plug Wires, Super Conductor, Spiral Core, 8.5mm, Red, Multi-Angle Boots, Universal, L8/V8, Set. $82.95
26. Edelbrock 1411 - Edelbrock Performer Carburetors. Carburetor, Performer, 750 cfm, 4-Barrel, Square Bore, Electric Choke, Single Inlet, Silver, Each. $319.95
27. Speed-Pro Forged Pistons Piston, Forged, Dish, 4.155 in. Bore, 5/64 in., 5/64 in., 3/16 in. Ring Grooves, Oldsmobile, 455, Each.
28. Spectre Performance 4733 Chrome Water Neck $22.95
29. Mondello Aluminum Oldsmobile Valve Covers.

 

Put it in the Impala. Chebby guys bastardize our cars without thinking twice. It's all GM, right?

 

Yeah they do. I went to a chevy forum and asked this question if it would fit into a 64 impala and everyone had jokes. No one answered my question because they were to busy telling me I would have one of a kind impala.

I am not a Chevy guy but for the price I got it for and the car and being a super sport I couldn't pass it up. As soon as I can get this 327 rebuild I will sell it and look for a 442. I still want to sell my 455 engine so I can have more money so I won't be buying a fixer upper.

 

I really like this idea. Most deffinately it could be done. Anything can be done with time and money. There would be a bit of fabricating and customizing. It sure would be fun but you would certainly lower the value to the purists. In 1969 the 455 with a four barrel had 390 HP from the factory with shallow dish pistons. You have upgraded the cam and intake but I'm not sure you have enough upgrades there to put you @ 450 HP. There's one way to find out. Pay the $400-$500 to have it dyno tested. Then you would know exactly what you've got there. It frustrates me to no end when your machinist can't even tell you exactly what the blue print specs are. That's like not wanting to tell you what they specifically did. Did they not maesure anything? Was it balanced? What clearences are they running on the rods & mains? Were there any oiling mods done? Good luck with your sale. From my experience you may be better off parting out this engine.

 

375hp. You don't have enough cam and compression to produce any more than that.

And the factory specs were a bit hyped. Plus they had much better fuel back then as well.

 

Plus, don't forget that those are SAE Gross numbers, and the convention today is to measure SAE Net instead, which will subtract maybe 50-100HP, depending on the underlying hype level.

- Eric

 

Only one way to find out..Dyno Test:-)