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| is this rebuild combo a waste of time? https://slantsix.org/forum/viewtopic.php?t=24298 |
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| Author: | drtwgn [ Wed Aug 01, 2007 4:02 pm ] |
| Post subject: | is this rebuild combo a waste of time? |
Most of the mild rebuilds discussed include a 2 bbl , duals, a slightly higher than stock cam, and porting, and roughllly 9:1 comp ratio. My plan, which keeps costs down, would be: Keep the carter 1 bbl dual exhaust porting head and original valves the stock cam and degreeing cam electric fan shaving block enough to get 8.5 - 9.0 : 1 comp ratio. keep the 2.76 rear end Woudl this combo be an improvement in mpg, and useful for every day driving, or is the carb or cam limiting the usefulness of the other mods? Or, should I just go ahead and do it, and see how well it works? THanks gurus |
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| Author: | Matt Cramer [ Wed Aug 01, 2007 4:14 pm ] |
| Post subject: | |
If the engine's wearing down, a rebuild is not a waste of time. I'd imagine the duals and electric fan would make significant changes, although these days you can get high flow single exhausts at reasonable prices. Just don't get carried away with the port job; you don't want a 6,500 RPM head with a 4,000 RPM cam. |
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| Author: | 65deuce [ Wed Aug 01, 2007 4:47 pm ] |
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An aftermarket cam with OE lifters is not significantly more expensive than a new stock replacement. It' one of those thing that just make sense. Even leaving stock induction....what if you eventually want more, at least the cam is done. My $.02 |
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| Author: | icaneat50eggs [ Wed Aug 01, 2007 5:19 pm ] |
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I have found the two barrel swap to give me better milage. |
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| Author: | Matt Cramer [ Thu Aug 02, 2007 5:17 am ] |
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Quote: I have found the two barrel swap to give me better milage.
Me too - the BBD seems to give slightly better mileage than a Holley 1920. That's probably why most of the rebuild threads include a Super Six - there are not much of any downsides to this upgrade.
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| Author: | Charrlie_S [ Thu Aug 02, 2007 6:06 am ] |
| Post subject: | Re: is this rebuild combo a waste of time? |
Quote: Most of the mild rebuilds discussed include a 2 bbl , duals, a slightly higher than stock cam, and porting, and roughllly 9:1 comp ratio.
Are you going to do a complete rebuild, or just add the new parts?My plan, which keeps costs down, would be: Keep the carter 1 bbl dual exhaust porting head and original valves the stock cam and degreeing cam electric fan shaving block enough to get 8.5 - 9.0 : 1 comp ratio. keep the 2.76 rear end Woudl this combo be an improvement in mpg, and useful for every day driving, or is the carb or cam limiting the usefulness of the other mods? Or, should I just go ahead and do it, and see how well it works? THanks gurus If it were me (and it was) I would build it with a .060 stock piston (honed with block plate if possible), Mild cam (mopar 243, or similar)degreed in, milled head to get an honest 9.0-1 compression ratio (forget milling the deck) 2 1/4-2 1/2 single exhaust with low restriction muffler. Stock 1 bbl or super six. Recurve distributer. MPG Fanatic and I did a similar engine last year (1 bbl holley), in a 64 Valiant 3 speed standard trans, and he is reporting about 27 mpg. We also balanced the rotating assy, and no porting on the head (i don't think it is worth the effort for what you want) |
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| Author: | drtwgn [ Thu Aug 02, 2007 8:52 pm ] |
| Post subject: | Re: is this rebuild combo a waste of time? |
Your replies help. Yes, a complete rebuild. Just looking for best MPG possible, and best pep from basically a stock motor (a 225). Not looking to race. Now, of these cams, which would be OK for "clean up" porting and the 1 bbl, and the 2 1/4 dual exhaust? comp 252 erson 270 mopar 243 (is this the stock mopar?) other? THese numbers refer to duration, right? And the greater the duration, the better the........? ANd, the decimal numbers, e.g., .425 , refers to lift, right? And the higher the lift the better the.........? THanks again |
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| Author: | Aggressive Ted [ Thu Aug 02, 2007 10:15 pm ] |
| Post subject: | Best mileage rebuild |
I just went through the same process.......... The engine is almost broke in. I have a few things that are not tuned yet, like the distributor recurve, installing the good Aussie gaskets to eliminate some vacuum and exhaust leaks and fixing a harmonic balancer seal leak, and blocking off the EGR, but I am almost there. I drive 128 miles a day. If I could restrain myself from getting on it so often and drive a little slower and do the above fixes, I am sure the mileage would be much higher. I find myself cruising around 70 (2700 rpm) instead of 60 (2500) rpm and passing every Mustang GT I find on the back roads. Plus town driving is kind of fun now with so much extra power. It is fun to bust the wheels loose (posi) now and then. Most folks can't believe it is a SL6 much less a fair to poorly tuned one. Once everything is finished I should take it on a trip to see what it will do. Then down the drag strip, SIR is 10 miles away to see what it will do there. I think your rebuild is right on and your right about the cam numbers. You can cross reference with my rebuild and PM me for pictures and questions. |
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| Author: | newpoppop [ Fri Aug 03, 2007 1:30 pm ] |
| Post subject: | perf ??? |
i have a .060 over, comp cam, 4 bbl hyperpak setup, clifford shorty headers, i am not sure what size I need the exhaust to be... any suggestions on mufflers and pipe size?? |
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| Author: | Aggressive Ted [ Fri Aug 03, 2007 2:59 pm ] |
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Most folks will tell you to use a "Y" pipe to join them and one single 2.5" out the back. Saves weight, etc......... If you have a serious build, I would try (2) 2.25" pipes with and "X" pipe for some serious power. How big is the cam and what is the compression ratio? If it is a mild build, go with the first option. |
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| Author: | MenkeMoose [ Fri Aug 03, 2007 5:35 pm ] |
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I'm right in the middle of this process as well. I went with Dan's recommendation of a Mopar 244 cam, which is available from Doc. Unfortunately, I don't have it all together yet, so I can't tell you how I like it. I also bought a Dutra front manifold and am fabricating the rear from the original. -Moose |
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