Compression ratio

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RustyRatRod said:
I'm gonna say that engine is most likely in the 10-10.5 range. That's a 64 cc head and a 2 eyebrow piston. It's at least in the mid to high 9s. Probably a decent little motor.
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not likely with the composite gasket, steel shim. maybe
 
yellow rose said:
I would have given this nice, short answer, but some blow hard would come along and tell me I don't add anything to these threads (not you rumble) so I gave the long version.
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Guys, you ain't gonna get any heat from me. I appreciate any help you can offer. I'm trying to get myself back into the mood to tackle the task of rebuilding this Duster. I was expecting at least the factory performance from the engine, but was hoping for a bit more. It's got an Edelbrock Air Gap intake, and a Comp Cams HE268 cam. The block was decked, also. Running a Holley 670 Street Avenger carb.
 
70Duster340 said:
Guys, you ain't gonna get any heat from me. I appreciate any help you can offer. I'm trying to get myself back into the mood to tackle the task of rebuilding this Duster. I was expecting at least the factory performance from the engine, but was hoping for a bit more. It's got an Edelbrock Air Gap intake, and a Comp Cams HE268 cam. The block was decked, also. Running a Holley 670 Street Avenger carb.
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I think it will certainly surpass that of a stock 340.
 
70Duster340 said:
Guys, you ain't gonna get any heat from me. I appreciate any help you can offer. I'm trying to get myself back into the mood to tackle the task of rebuilding this Duster. I was expecting at least the factory performance from the engine, but was hoping for a bit more. It's got an Edelbrock Air Gap intake, and a Comp Cams HE268 cam. The block was decked, also. Running a Holley 670 Street Avenger carb.
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That wasn't directed at you. Some other joker in another thread.
 
70Duster340 said:
Guys, you ain't gonna get any heat from me. I appreciate any help you can offer. I'm trying to get myself back into the mood to tackle the task of rebuilding this Duster. I was expecting at least the factory performance from the engine, but was hoping for a bit more. It's got an Edelbrock Air Gap intake, and a Comp Cams HE268 cam. The block was decked, also. Running a Holley 670 Street Avenger carb.
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I like your combo, it should perform well . a proven combo used by many.
 
  • 60179's are the 'open chamber' version of the Edlebrock heads with 65 cc chambers.
  • The head gaskets sound like Felpro 1008's
  • The most likely pistons would be about .018" above deck, Or maybe even .012 below deck for one certain type. if the deck has not been cut.
If .012 below deck, SCR is right around 9.5.
If true zero deck, SCR is right around 9.7.
If .018 above deck like stock pistons, then SCR is right around 10.1

OP, the original factory CR is, and was, not real for production engines. You only get there with the original thin head gaskets and the NHRA minimum spec chambers sizes. Typical production CR's seem to run 0.5 to 0.75 points below advertised.

Don't worry about it..... your power is going to come from the improved head flow that you now have. You have good SCR as is, unless you have some massive cam in there.

Edit to add: I see the cam now.... an older type but this engine is going to be a very good street engine.... plenty of low RPM torque and ought to wind out very well. You ought to enjoy it... put in more money in your tire budget LOL.

Learn about ignition timing and be cautious in tuning. You won't need a lot of extra ignition advance in this engine.
 
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The head will flow better than a stock head. Not much but better. The intake is better than stock. Watch out for the exhaust manifold hitting the head on the drivers side. You may need to buy an header flange to space the manifold out from the head. Also there can be alternator fitmen issues with the eddu head. Nothing that can’t be overcome. Just something to keep in mind.
 
Thanks everybody for the input. The pistons are not stock, but when he purchased them he insisted on forged pistons. Said they were stronger than stock. I know they bored it .030 over, and decked the block and also bore aligned it. I don't know the numbers on the deck or the bore alignment. I thought he was doing a good job. As for the stock manifolds, I already ran into that problem. I have a header flange to fit that side. I had contacted Edelbrock about this issue, but they couldn't offer a solution other than recommending headers. I already have the HP manifolds, and prefer to use them. This is being mated to an 833, and 8.75 rear diff with 3.91's and anti-spin.
How does that sound to you experts?
 
Exhaust manifolds are a personal choice to run that looses power to headers. At your level, it’s not huge but a little noticeable. I wouldn’t worry a bit. There are good reasons run exhaust manifolds.

What size rim and tire?
 
rumblefish360 said:
Exhaust manifolds are a personal choice to run that looses power to headers. At your level, it’s not huge but a little noticeable. I wouldn’t worry a bit. There are good reasons run exhaust manifolds.

What size rim and tire?
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The wheels are 14 inch, rear tires are 245-60R14's. It had headers when I bought it, but they were cheap ones and I had to cut them off.
 
70Duster340 said:
Thanks everybody for the input. The pistons are not stock, but when he purchased them he insisted on forged pistons. Said they were stronger than stock. I know they bored it .030 over, and decked the block and also bore aligned it. I don't know the numbers on the deck or the bore alignment. I thought he was doing a good job. As for the stock manifolds, I already ran into that problem. I have a header flange to fit that side. I had contacted Edelbrock about this issue, but they couldn't offer a solution other than recommending headers. I already have the HP manifolds, and prefer to use them. This is being mated to an 833, and 8.75 rear diff with 3.91's and anti-spin.
How does that sound to you experts?
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You do lose a good amount with exhaust manifolds, but you can run pretty well with the manifolds. I just lost to an AAR running those manifolds. He ran 11.80 at 119mph. I’m surprised edelbrock didn’t say “gee, I never heard of that problem before!”
 
LOL! @furrystump Indeed! The manifolds are good. I bet that guy spent a little more time on the build than the average Joe if that was his purpose to go fast with them.
A Wolf in sheep’s clothing. I can totally dig that.

Anybody know that tire diameter above to the 245/60/14’s?
 
70Duster340 said:
Thanks everybody for the input. The pistons are not stock, but when he purchased them he insisted on forged pistons. Said they were stronger than stock. I know they bored it .030 over, and decked the block and also bore aligned it. I don't know the numbers on the deck or the bore alignment. I thought he was doing a good job. As for the stock manifolds, I already ran into that problem. I have a header flange to fit that side. I had contacted Edelbrock about this issue, but they couldn't offer a solution other than recommending headers. I already have the HP manifolds, and prefer to use them. This is being mated to an 833, and 8.75 rear diff with 3.91's and anti-spin.
How does that sound to you experts?
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3.91's are about the max for street fun machines with no overdrive. Limited freeway use is best with this gear. Unless you can tolerate high revs on highway.
 
QuickDart360 said:
3.91's are about the max for street fun machines with no overdrive. Limited freeway use is best with this gear. Unless you can tolerate high revs on highway.
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No plans on highway use. Just a pleasure vehicle. Maybe a car show occasionally, if it's worthy of showing.
 
rumblefish360 said:
LOL! @furrystump Indeed! The manifolds are good. I bet that guy spent a little more time on the build than the average Joe if that was his purpose to go fast with them.
A Wolf in sheep’s clothing. I can totally dig that.

Anybody know that tire diameter above to the 245/60/14’s?
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"Around" 25.5" depending on who makes it.
 
QuickDart360 said:
I bet that ride is a real neck snapper!! Fun as heck too. Wish I were brave enough to go with that gear.
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Be brave and just do it. Just grab different wider and taller tires. LMAO! I did 4.88’s in my Duster for Ha-Ha’s and I love’em. No, I don’t do the Hwy and limit around town speeds to 40 mph, which doesn’t bother me at all and yes I’ll travel 40 or so miles 1 way with them.
 
I find a steeper gear is easier to control. When a 3:23 starts spinning it can almost take divine intervention to stop it, but 4:10 you just don’t get the wheel speed which makes it easier to peddle it.
 
furrystump said:
You do lose a good amount with exhaust manifolds, but you can run pretty well with the manifolds. I just lost to an AAR running those manifolds. He ran 11.80 at 119mph. I’m surprised edelbrock didn’t say “gee, I never heard of that problem before!”
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Yeah, can you believe that? I would have expected them to offer some sort of fix, but the only advice they would offer was to switch to headers. I would have thought that they would have been aware of the issue, but I guess fix would be to re-engineer the heads, which would cost more than the problem was worth.
 
The alternator is worse, you could make an argument that most will run headers, but no alternator, unless you change the brackets and get a longer belt or run a smaller one.
 
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