Smallblock efficiency or How to have your cake and eat it too

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BigBlockMopar said:
No real need for overpriced MSD stuff; You can get a programmable ignition box for under $200 ( "Black Box" @ CB-Performance).

CB Performance Black Box Programmable Timing Control Module




The stall convertor currently in the 518-transmission is a late '60s stock 727 unit as found in C-bodies.
A believe 1" larger in diameter than the much newer convertors used in the '90/'00 OD-transmissions, so, besides being heavier, it's probably having more resistance/drag inside too.
I've had a smaller OD+Lockup trans and convertor in the car for a short time once and noticed the engine seemed to rev noticably quicker and wasmuch happier. I'm currently rebuilding that transmission and hope the install it again soon.
Click to expand...

PATC offers performance converters with upgraded clutches for lockup. On a street car I would use the lock up type. Only reason not to do so other than lock up converter issues is the hollow input shaft is not quite as strong as the solid non lock up version. I plan to build an A500 lockup to go behind my 340 EQ head build to gain a lower 1st gear, increase in efficiency, and smaller overall case and tail housing. If it were a 360 or stroker I would probably build a lockup 518 due to the torque curve coming in at lower rpm. PATC - Performance Automotive & Transmission Center
 
My recipe
360 magnum block with Quality machining ie line hone, torque plate hone, square decked
surface polished, knife edged, stroke equalized, and indexed factory crank with no hole balance job with bearing clearance on the tight side
windage screen and crank scraper coated bearings Milodon 7" pan
0 deck flat tops with 1.5mm or .043 rings thermal coated top and coated skirts
EQ heads 2.02 / 1.625 valves ported to 250ish cfm
hyd roller utilizing the factory roller lifter gear and 1.6 roller rockers
single pattern cam in the 230° @.050 range ground on a 112-114 +2° or 4° with as much lift as I can get
RPM Air Gap intake with 750 vacuum secondary Holley or dare I say it factory iron intake with Qjet and utilize the EGR system
properly curved vacuum advance distributor
TTI headers with 3" exhaust

I don't think it would pull down 500 HP more like 430-450, but it would turn in fantastic mileage when tuned right
 
skrews said:
My recipe
360 magnum block with Quality machining ie line hone, torque plate hone, square decked
surface polished, knife edged, stroke equalized, and indexed factory crank with no hole balance job with bearing clearance on the tight side
windage screen and crank scraper coated bearings Milodon 7" pan
0 deck flat tops with 1.5mm or .043 rings thermal coated top and coated skirts
EQ heads 2.02 / 1.625 valves ported to 250ish cfm
hyd roller utilizing the factory roller lifter gear and 1.6 roller rockers
single pattern cam in the 230° @.050 range ground on a 112-114 +2° or 4° with as much lift as I can get
RPM Air Gap intake with 750 vacuum secondary Holley or dare I say it factory iron intake with Qjet and utilize the EGR system
properly curved vacuum advance distributor
TTI headers with 3" exhaust

I don't think it would pull down 500 HP more like 430-450, but it would turn in fantastic mileage when tuned right
Click to expand...
id be interested on some mileage #'s when you can test it.
 
nm9stheham said:
What AFR are you tuning for at light/moderate cruise? 15-16 is what you want to be under those light load conditions to get to good fuel mileage.
Click to expand...

I'm tuning for:
  • WOT: 12.2, and hit that spot on.
  • Primary Acceleration: 14.0, actually achieve around 15.5 (don't like it, but it does accelerate and run good).
  • Cruise: 15.5, actually achieve around 13.9 (don't like it but it does run nice).
If I choose the very next available lean setting, it goes WAY too lean on primary acceleration.
If I choose the very next available rich setting, it goes WAY too rich on cruise.

So, it is optimized. Like I said, disconnect the AFR gauge and let anyone drive it, and they will talk about how great the car drives. A local shop that did the alignment for me, the owner of the shop told me his tech came back and said, "That ole Scamp runs good!"

And it does. I've tried to find a shop that could make custom metering rods that would hit my target AFRs, but have not found one. I have designed my own metering rods based on the accuracy of my spreadsheet in correlation to what the AFR gauge reads.

As far as the AFR readings, I don't pay attention to the AFR gauge until the engine is actually firing. And even as soon as it fires off, it responds to the engine exactly as I expect. Rich when choked. I get a rich spot when I blip the throttle and the pump shot hits. It was lean when cranking only when I had the 750 carb and I wouldn't pump the throttle or use the choke because I thought I was flooding it. It was only showing lean then … and that's when I realized HA, I'm not flooding it at all. I'm starving it. The AFR gauge showed me the error of my way. As soon as I went to choking and pumping, BOOM. Fires right up.

What threw me (what I didn't know), was back before the AFR gauge, I did pump the throttle a time or 2 before cranking, then a couple more times while cranking. But the carb was either empty or somewhat empty, so the pumping was actually pumping nothing (that's what I didn't know). But I thought I was pumping raw gas in at each time, and after a few pumps with no start, I though it was flooding … so I would stop pumping and keep cranking. After the AFR, I realized the pumping wasn't effective at first, until the carb filled. I now pump it continuously (if it hasn't started in a few days or more) and keep pumping until it hits a lick. After it hits a lick I slow the pumping down and it fires right off. After it cranks it has to be revved (gently) to have the pump shoot in even more raw gas to keep it running. It's a rhythm. But after 15 seconds of doing this, its ready to idle on its own, choked. This is all based on it not having run in a few days.

I drove it to work today. So when I crank it cold to go to lunch, it will require a bit of choke and just a pump or 2 and it will fire right up. Because the carb has gas in it from driving it this morning, so the couple pumps to crank it at lunch time are fully effective. Once the engine is warm after lunch, I just turn the starter, followed by a push of the pedal about a quarter way down (no choke), and it fires up quickly. The AFR gauge made starts quicker and easier by pointing out what was actually going on versus what I *thought* was going on.


7milesout
 
7milesout said:
I'm tuning for
Click to expand...

What type of carburetor and size are you running for what engine?

Sometimes after deployments (3 months) I only had two pump twice and hold the accelerator pedal half way and it would start right up. 600 cfm Holley, 1973 340+.030”, 4 valve-relief cast (low compression) pistons, 89 non-ethanol with stabil fuel stabilizer and sea foam diluting the fuel. Zero elevation.
Thank you!
 
@greymouser7

That fuel stabilization liquid is key. Good thinking.
What kind of air cleaner is up top? A factory styled closed unit?
 
7milesout said:
I'm tuning for:
  • WOT: 12.2, and hit that spot on.
  • Primary Acceleration: 14.0, actually achieve around 15.5 (don't like it, but it does accelerate and run good).
  • Cruise: 15.5, actually achieve around 13.9 (don't like it but it does run nice).
If I choose the very next available lean setting, it goes WAY too lean on primary acceleration.
If I choose the very next available rich setting, it goes WAY too rich on cruise.

So, it is optimized. Like I said, disconnect the AFR gauge and let anyone drive it, and they will talk about how great the car drives. A local shop that did the alignment for me, the owner of the shop told me his tech came back and said, "That ole Scamp runs good!"

And it does. I've tried to find a shop that could make custom metering rods that would hit my target AFRs, but have not found one. I have designed my own metering rods based on the accuracy of my spreadsheet in correlation to what the AFR gauge reads.

As far as the AFR readings, I don't pay attention to the AFR gauge until the engine is actually firing. And even as soon as it fires off, it responds to the engine exactly as I expect. Rich when choked. I get a rich spot when I blip the throttle and the pump shot hits. It was lean when cranking only when I had the 750 carb and I wouldn't pump the throttle or use the choke because I thought I was flooding it. It was only showing lean then … and that's when I realized HA, I'm not flooding it at all. I'm starving it. The AFR gauge showed me the error of my way. As soon as I went to choking and pumping, BOOM. Fires right up.

What threw me (what I didn't know), was back before the AFR gauge, I did pump the throttle a time or 2 before cranking, then a couple more times while cranking. But the carb was either empty or somewhat empty, so the pumping was actually pumping nothing (that's what I didn't know). But I thought I was pumping raw gas in at each time, and after a few pumps with no start, I though it was flooding … so I would stop pumping and keep cranking. After the AFR, I realized the pumping wasn't effective at first, until the carb filled. I now pump it continuously (if it hasn't started in a few days or more) and keep pumping until it hits a lick. After it hits a lick I slow the pumping down and it fires right off. After it cranks it has to be revved (gently) to have the pump shoot in even more raw gas to keep it running. It's a rhythm. But after 15 seconds of doing this, its ready to idle on its own, choked. This is all based on it not having run in a few days.

I drove it to work today. So when I crank it cold to go to lunch, it will require a bit of choke and just a pump or 2 and it will fire right up. Because the carb has gas in it from driving it this morning, so the couple pumps to crank it at lunch time are fully effective. Once the engine is warm after lunch, I just turn the starter, followed by a push of the pedal about a quarter way down (no choke), and it fires up quickly. The AFR gauge made starts quicker and easier by pointing out what was actually going on versus what I *thought* was going on.


7milesout
Click to expand...
OK, got it... nice write up! BTW, aren't the Edelbrock carbs prone to the fuel evaporating or boiling out when hot? Perhaps that is a factor.
 
nm9stheham said:
OK, got it... nice write up! BTW, aren't the Edelbrock carbs prone to the fuel evaporating or boiling out when hot? Perhaps that is a factor.
Click to expand...
Yes as well as with any aluminum carb that runs a thin gasket instead of the thicker (.333 -ish) thick gasket.
 
nm9stheham said:
OK, got it... nice write up! BTW, aren't the Edelbrock carbs prone to the fuel evaporating or boiling out when hot? Perhaps that is a factor.
Click to expand...
It doesn't have these issues at any time the engine is running. It may evaporate from sitting for days, but no carb/heat issues (for me). I do run a thicker gasket, it may be about 1/3rd inch or so thick.
 
nm9stheham said:
OK, got it... nice write up! BTW, aren't the Edelbrock carbs prone to the fuel evaporating or boiling out when hot? Perhaps that is a factor.
Click to expand...

A phenolic, pressboard, or wood spacer between the intake and carb would reduce heat soaking the carb and problems related to it.
 
MOPAROFFICIAL said:
I haven't read past the first page , I intend to ,don't get me wrong, but I stopped and thought right away after reading the the first post back too and I would always tell people how important running in in or near the middle of the cam Power Band. People would laugh and say "oh yeah ? okay well my power bands 3000-7000... so I'll go down the freeway at 4500..huh... yeah right" ...but thing is...you get worse milage under the cam range. You want to get as much of your low speed driving into the cam range as possible. It runs dirty if you dont and the gas is going out the tail pipe.
I still have the five pages to read and in fact earlier I was wondering where this thread went cuz I only saw the first post when he first put it up.... but basically when we spend all our time on the site talk and a heck of a lot about making power and doing it expensive or cheaper ,his way, my way, or their way ...we don't really dive into the other end of the pool, where we started from. I think about all the the 70-71 dusters that were ordered up with 4 wheel drum .. on purpose. They drag less and you went faster that way.. that works for milage too...anyways, i gotta read all this to see IF there is anything new i havent already known about. Cracking beer now...
Click to expand...

I agree with this. When I bought my Ram 1500 I could not find any ordered with 3.91s..( Or sure grip ..or the big tank. A whopping 350$ in options !)
My truck lugs at anything below 75 mph with 3.55s..
Hemis are not efficient at low rpms.
 
mbaird said:
I agree with this. When I bought my Ram 1500 I could not find any ordered with 3.91s..( Or sure grip ..or the big tank. A whopping 350$ in options !)
My truck lugs at anything below 75 mph with 3.55s..
Hemis are not efficient at low rpms.
Click to expand...
It’s not the Hemi, it’s the cam/gearing/usage/timing etc.

David Vizard praised the flow/design of the new Hemi’s compared to all modern contemporary wedge heads-specifically low flow characteristics.
 
RAMM said:
Some posters have a very good understanding of how and why a powerful old school V8 can actually be reasonably efficient. I don't have a lot of time today but tomorrow I would like to re-visit and add a few more points of discussion.

For now though ignition timing is worth spending some time discussing. Getting the timing curve perfect for all driving conditions is not possiblewith just a mechanical advance system. I strongly urge anyone willing to look at a programmable ignition such as:

MSD 6530 MSD Digital Programmable 6AL-2

For those that want more mileage out of their hot small blocks please keep reading and add to the discussion. J.Rob
Click to expand...


I am glad you brought this up.
I am running a Daytona Sensors CD-2 programmable ignition on my 408 and need some advice on a baseline curve. I locked out the dizzy...
W2 Close chamber race heads ported by SD to 297 cfm
.032 Quench
Solid roller 246/250 @ .050
.648 lift with 1.6 rockers
TTI 1 7/8 to 3" full exhaust
Victor Intake
Custom Pro systems carb 900 ish cfm
Gears will be 3.55s for street.
Car is a 4sp 69 340 Swinger.
 
greymouser7 said:
It’s not the Hemi, it’s the cam/gearing/usage/timing etc.

David Vizard praised the flow/design of the new Hemi’s compared to all modern contemporary wedge heads-specifically low flow characteristics.
Click to expand...
Well I drive like G-ma ...lol
I am surprised that DV likes the low flow... I would assume that big of port stalls at low rpm.
 
mbaird said:
Well I drive like G-ma ...lol
I am surprised that DV likes the low flow... I would assume that big of port stalls at low rpm.
Click to expand...


Not always. A port with good low lift can carry it through the lift curve but I've never agreed with DV and his thoughts on low lift flow. I really could care less about low lift flow. If the port is correct low lift really means little except at overlap and that's when big low lift flow numbers kill power. And then to fix it, guys want cams with early closing intakes and wide LSA's and it's just a bandaid for a poorly thought out port and valve job.
 
7milesout said:
I'm tuning for:
  • WOT: 12.2, and hit that spot on.
  • Primary Acceleration: 14.0, actually achieve around 15.5 (don't like it, but it does accelerate and run good).
  • Cruise: 15.5, actually achieve around 13.9 (don't like it but it does run nice).
If I choose the very next available lean setting, it goes WAY too lean on primary acceleration.
If I choose the very next available rich setting, it goes WAY too rich on cruise.

So, it is optimized. Like I said, disconnect the AFR gauge and let anyone drive it, and they will talk about how great the car drives. A local shop that did the alignment for me, the owner of the shop told me his tech came back and said, "That ole Scamp runs good!"

And it does. I've tried to find a shop that could make custom metering rods that would hit my target AFRs, but have not found one. I have designed my own metering rods based on the accuracy of my spreadsheet in correlation to what the AFR gauge reads.

As far as the AFR readings, I don't pay attention to the AFR gauge until the engine is actually firing. And even as soon as it fires off, it responds to the engine exactly as I expect. Rich when choked. I get a rich spot when I blip the throttle and the pump shot hits. It was lean when cranking only when I had the 750 carb and I wouldn't pump the throttle or use the choke because I thought I was flooding it. It was only showing lean then … and that's when I realized HA, I'm not flooding it at all. I'm starving it. The AFR gauge showed me the error of my way. As soon as I went to choking and pumping, BOOM. Fires right up.

What threw me (what I didn't know), was back before the AFR gauge, I did pump the throttle a time or 2 before cranking, then a couple more times while cranking. But the carb was either empty or somewhat empty, so the pumping was actually pumping nothing (that's what I didn't know). But I thought I was pumping raw gas in at each time, and after a few pumps with no start, I though it was flooding … so I would stop pumping and keep cranking. After the AFR, I realized the pumping wasn't effective at first, until the carb filled. I now pump it continuously (if it hasn't started in a few days or more) and keep pumping until it hits a lick. After it hits a lick I slow the pumping down and it fires right off. After it cranks it has to be revved (gently) to have the pump shoot in even more raw gas to keep it running. It's a rhythm. But after 15 seconds of doing this, its ready to idle on its own, choked. This is all based on it not having run in a few days.

I drove it to work today. So when I crank it cold to go to lunch, it will require a bit of choke and just a pump or 2 and it will fire right up. Because the carb has gas in it from driving it this morning, so the couple pumps to crank it at lunch time are fully effective. Once the engine is warm after lunch, I just turn the starter, followed by a push of the pedal about a quarter way down (no choke), and it fires up quickly. The AFR gauge made starts quicker and easier by pointing out what was actually going on versus what I *thought* was going on.


7milesout
Click to expand...
This is a perfect example, (argument) to switch to EFI...you'll never look back...Put key in,,turn key,,drive.
 
LJ67barracuda340 said:
This is a perfect example, (argument) to switch to EFI...you'll never look back...Put key in,,turn key,,drive.
Click to expand...
Vice approximately $200 bucks for a carb versus $700++ for FiTech, $2K + Holley or FAST... PLUS, if you’re converting to EFI - cutting/drilling bung holes for sensors (lifting the car, maybe more for big blocks) it is simply a money and convenience matter.

My friend, a certified electrician, took two weeks to sort his EFI out with more time off (shore duty) than most anyone here has. He worked on it around the clock.

It tamed his camshaft, solved some problems-but many of the older guys here can get in and turn their key and drive at will. When I drove regularly, I could get in and go-every time.

Separate subject for another thread.
 
greymouser7 said:
Vice approximately $200 bucks for a carb versus $700++ for FiTech, $2K + Holley or FAST... PLUS, if you’re converting to EFI - cutting/drilling bung holes for sensors (lifting the car, maybe more for big blocks) it is simply a money and convenience matter.

My friend, a certified electrician, took two weeks to sort his EFI out with more time off (shore duty) than most anyone here has. He worked on it around the clock.

It tamed his camshaft, solved some problems-but many of the older guys here can get in and turn their key and drive at will. When I drove regularly, I could get in and go-every time.

Separate subject for another thread.
Click to expand...
Not to start a fight,,,I haven't seen a Good $200 carb in decades,, certified electrician is not the same as a certified auto technician,, I'm not a wizard but it took 5 hours to sort out a previous owner wiring on a chevy with a Sniper EFI. Big Block$$ Small Block$$ dont get that,,, lifting the car????? The only Bung Hole needed is for the O2 in the exhaust, lots of Carb guys are putting them in for AFR gauges anyway,,I'm on board with EFI...More $$ but worth it..Plus it can control the timing +++++. thought this thread was about efficiency not how to stay Old Skool.
 
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LJ67barracuda340 said:
Not to start a fight,,, I thought this thread was about efficiency not how to stay Old Skool.
Click to expand...

Well he did state it in the first post:

RAMM said:
What if I told you an LA engine that was carb'd , solid flat tappet, vac distributor going down the highway @ 2800-3200 rpm could make 450-500HP and still knock down 18-20 mpg?
Gotta run , I will be back for Part 2. J.Rob
Click to expand...

My experience has shown me yes the cookie cutter EFI is great if they don't know how to tune a carb or if you have deep pockets and love the self adjusting feature for when you're changing altitudes and such. Don't get me wrong I think they are nice units just not $1200+ nice. I can (and have) tuned my brand new $400 Street Demon 750 (again I know how to fiddle with carbs) for decent mileage and super easy startups even in 20° temps (MSD 6A helps I'm sure). Yes you can get a decent carb for $200. I was able to get a slightly used/refurbished Eddy 650 AVS for $230, and it worked beautifully replacing my 25 yr old Carter AFB that I used since high school in my first car, a 1984 dodge Ramcharger + 2 other cars including the duster until it was replaced with Street Demon.
And yes I have looked into EFI it's just not economically sound enough for me:
FiTech Go EFI 4 600: $925
Hyperfuel Go EFI Fuel Command: $395
Total: $1320
That's not including the other nit-noid items that may be needed.
To me the biggest bang for mileage-wise would be to use that money towards an overdrive system to net better results.

That said I also love riding around in my 37/40mpg Vulcan 1700 Vaquero if I'm feeling economical.
It is "new school" Fuel Injected but hey I still love it!
 
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When I had my '73 Duster 340/4 speed ('71 clone) I ran:
-Mopar replacement electronic dist from NAPA
-ThermoQuad 750
-GM HEI module conversion eliminating mopar ECM & ballast
-NGK plugs gapped to about .40-.42....initial timing at about 16 BTDC w vacuum advance.

I tested the fuel mileage a few times, under "normal muscle car" driving conditions = basic highway speed, with once or twice hammering it, opening the 4 BBL to pass with authority LOL
I would always get 26-28 MPG and thought that to be pretty good, considering an average new vehicle with all the sensor BS and EFI would struggle to get that!
 
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