Check out my past posts on this subject for reference. I have listed the build sheet. It is a good basic upgrade that provides plenty of spunk.
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| Whats the best rebuild for m.p.g and pep? https://www.slantsix.org/forum/viewtopic.php?t=25687 |
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| Author: | 225rt [ Sun Nov 04, 2007 6:13 pm ] |
| Post subject: | Whats the best rebuild for m.p.g and pep? |
I am ready to rebuild my 1974 225. Its in a 1968 b-body dodge. The engine is a 1974 225, I have a clifford header, super six 2 bbl intake. I have it behind a 833 o/d trans and a 3.54 rear gear. Its got stock compression. I need input on what cam to run, how much to mill the head and what valves I should run. Im looking for some pep but good gas mileage. Any help is appreciated. Thanks Tim (The only guy in the United States converting from big block to slant six) |
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| Author: | Aggressive Ted [ Mon Nov 05, 2007 8:39 am ] |
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Check out my past posts on this subject for reference. I have listed the build sheet. It is a good basic upgrade that provides plenty of spunk.
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| Author: | emsvitil [ Mon Nov 05, 2007 11:56 am ] |
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Quote: Check out my past posts on this subject for reference. I have listed the build sheet. It is a good basic upgrade that provides plenty of spunk.
Give the new guy a break and give him a link........
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| Author: | DusterIdiot [ Mon Nov 05, 2007 6:07 pm ] |
| Post subject: | Define good MPG... |
Quote: Im looking for some pep but good gas mileage
Your setup is pretty good for a start, I gotta ask where you want to define good MPG and how much power... Since you've got a heavier rear, and the late B-Body with a couple of guys in it are about 3500 lbs (with a 'battleship' front cross-section wind wise)... A Basic build with a little more cam and bumping the compression up to 9:1 is a good start... dial in the timing and you should get 21 mpg and have about 160hp +/-... (If you really 'went down the rabbit hole'...) A set of 3.91's, a 4 barrel with a 390 Holley, Offy intake, dial the timing in, and shave the head/ block to acheive about 9.2:1 or a smidge more... would go far... along with a short duration, moderate lift cam (like Doc has perscribed), can be fun and economical -D.Idiot Of course I lug around a Duster that weighs as much as your car, so I'd be up for the 3.91's the baby Holley on a Hyperpak intake sporting Dutra Duals, so the long ram/ midrange torque helps getting that body off the line... but I digress... and it's a fair amount of work.... |
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| Author: | 225rt [ Mon Nov 05, 2007 8:09 pm ] |
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Thanks alot, 21 mpg with some pep is what im looking for. The car was a big block 440 and I want to drive it 42 miles a day to work. Does the comp cam 252 duration 435/435 cam sound ok. How much should I mill the head and do I leave stock size valves with 3 angle under cut valve job or the 1.70 1.44 valves? |
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| Author: | Aggressive Ted [ Sat Nov 10, 2007 3:37 pm ] |
| Post subject: | Pep and Mileage |
| Author: | Eric W [ Sat Nov 10, 2007 7:15 pm ] |
| Post subject: | Re: Pep and Mileage |
Quote: 1920 Holley tricked out
Please...do tell!  I drive 80 miles a day (I work at Boeing also) and currently get about 22mpg, but anything to help out would be nice. |
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| Author: | Aggressive Ted [ Sun Nov 11, 2007 3:13 pm ] |
| Post subject: | Tuning a Holley 1920 |
Eric, I drive from Black Diamond up to Everett everyday (120 mile round trip). One of the guys I know in the Boeing Strato-Cruisers Car Club turned me on to Joe's Carburetors Inc. 5516 186th PL S. W. Lynnwood, WA 98037 (425) 774-5504. Joe is the owner and can tell you alot about how to tune the 1920 and the SL6 timing for best mileage. He might be in his late 60's or early 70's, super nice and has all the parts in stock. He has all kinds of tricks on making the 1920 perform better. Since we have been scraping ice off the windows out here in the foot hills, my mileage dropped to 22 as well. However, I am running 15-40 Valvoline diesel truck oil since break in for the extra zinc. SlantSixDan says its time to change to 5-30 Mobil 1. So next oil change I will give it a try. Too thick of oil really effects windage and drag. I get better mileage on 4 quarts compared to 5 quarts. I had been playing with jets again because of what I thought was a lean surge, but I was just overtimed, 62 degrees. I did a recurve and was still running 20 degrees initial. I had to back it down to 16 degrees initial. I only felt it when I backed off the gas going down hill to Issaquah or when I tried to slowly rev it up in the yard, it would miss, idle was fine and no pinging. I still have a 58 jet in there, which is pretty fat, and need to pull it and go back to the #57 or try a #56. SL6 Dan says he can run his 71 Dart with an Economaster carb on the stock 552 jet with no problems. I will have to give that a try. Here are some of the tips (Joe) shared with me one day after I told him how far I drive. I went through this on a couple of 1920 carbs. On the first one a 1963 and the second one a 1973 or newer Economaster the check balls were not in place, rolling around in the bottom and the economiser pump gasket overlapped the accelerator pump squirter hole a little too much when the screws were snugged tight. When the carb is apart you can find the accelerator pump squirter hole by squirting carb cleaner through the different holes. (Joe) sold me a good accelerator pump gasket, the one that the economiser body sandwiches. He punched a larger hole in it for the accelerator pump to squirt through. I also took out all of the slop in the linkage that goes to the plastic cam and reamed the cam slightly so it rotates easily. He also sold me a thinner gasket to put under the vacuum actuated power valve which makes it engage quicker, and sold me a new plastic arm. No more gap between the plastic power valve arm and the piston. Now I get a very healthy squirt and boost which will break the P235 60 14 tires loose with a 2.76 posi-traction 8 3/4 rear end. Now that is quite a bit of power for a single barrel. From what I had before, this was a heck of an improvement. I will stay with the little Holley 1920 until I can find a good 4 barrel set up. Most folks don't believe it until I show them. I am very happy with what a one barrel can do.
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| Author: | Eric W [ Mon Nov 12, 2007 12:19 am ] |
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Thanks Ted. I also run a #58 jet...I cant seem to find a #57 locally. I tried a #55, but it was bog city off the line and I could really feel a lean surge at my usual driving speeds (60-70mph). Like the idea of punching a bigger hole in the gasket. I can use one of my dads leather working tools (one that is used to punch holes in belts for the belt buckle) to do that. I set my distributer up with a light spring and a four coil heavy spring, with the loop cut down some so full mechanical advance comes on slower. This is with an eleven governor. This gets me about 38* total advance with the vacuum advance hooked up...I'll have to check again. Your cam must like more initial advance, if I go any over 8* it will ping pretty bad the way my distributer is set up. As it is now, set at 5*, it pings some on steep hills around town, but dos'nt when pulling hard on the freeway (for passing, accelerating on onramps, etc). I try to set the engine up for the driving I do, which is 90% freeway. One of the things I still need to do is get an after market electric choke kit Dan recommends. I'm done screwing with mine (a '73 electric assist choke). Nice to see I'm not the only one intrested in fuel economy! Oh yeah, any thoughts on the power valve? |
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| Author: | Aggressive Ted [ Mon Nov 12, 2007 10:13 am ] |
| Post subject: | Tuning a Holley 1920 |
Eric, The power valve gaskets that come in the kits are too thick which seems to leave a space between the power valve piston and the plastic plunger arm. The thinner gasket Joe sold me reduces the gap. Joe mentioned another trick he does is if you want to use the thick stock gaskets, JB Weld a small washer on the piston plunger to take out some of the gap. Since my 63 carb had a deformed plastic plunger I bought a new one from him. Works great with the thinner gasket! When I switched to the Economaster version of the 1920 it has a dual plunger for twice as much fuel. Mine was twisted pretty bad and wasn't working. Back to Joe's for one of those. Now my Economaster comes on hard with both plungers engaging and no slope or gap in the power valve. It also helps to make sure the vacuum hole is not covered or plugged up. Be sure the carb cleaner goes through vacuum port easily and the gasket lines up. Mine use to whistle so a super thin layer of silicone may be required to seal the surfaces on the power valve. That should cover the power valve circuit. Hope it helps!  I have no lag or hesitation when I press on the gas pedal. It is very sensitive and responsive at any speed for a carb. I am not sure why the 254D .435 lift cam works so well. I haven't gotten it to ping yet since I built it which really seems odd. It is advanced 4 degrees on install. My car is 3500 pounds with me in it. For a one barrel it is very responsive at any rpm up to about 2700 rpm then it goes flat. Need more juice! Doctor Dodge asked me what I wanted, and that was torque (pep) and mileage. And that is what I have......thanks to the Doctor By the way, Joe can sell you a #57 jet. |
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| Author: | Eric W [ Mon Nov 12, 2007 10:22 am ] |
| Post subject: | |
Thanks Ted. I'll try and swing by Joes place this week. |
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| Author: | dusterdude225 [ Tue Nov 13, 2007 2:59 pm ] |
| Post subject: | |
now here is where it gets tricky you can get better mpg by reducing paracidic drag other words flex fans good plugs (boche has some with 2 electrodes for good gas and more umph) set your timeing right k&n air filters are soposed to help alot but it didnt help our s-10 keep your suspition right and have your tires fully inflated |
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| Author: | Charrlie_S [ Tue Nov 13, 2007 5:15 pm ] |
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Quote: now here is where it gets tricky you can get better mpg by reducing paracidic drag other words
Don't agree with flex fans. Thermostatic clutch fans, yes. Flex fans, no.flex fans good plugs (boche has some with 2 electrodes for good gas and more umph) set your timeing right k&n air filters are soposed to help alot but it didnt help our s-10 keep your suspition right and have your tires fully inflated Never had any good results with Bosch plugs in anything. I like NGK or Autolite. K&N filters will help by removeing weight from your wallet, but a nice clean quality paper filter will get just as good fuel milage. |
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| Author: | DusterIdiot [ Tue Nov 13, 2007 9:11 pm ] |
| Post subject: | Stub Stack... |
Quote: K&N filters will help by removeing weight from your wallet, but a nice clean quality paper filter will get just as good fuel milage.
I agree, but their stub stack has been run and does show better performance in the V-8 circles...(which probably equates out to a whole 3-5 hp for us 4 barrel guys... LOL) -D.Idiot |
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