|
Post by tiger13e on Apr 15, 2014 16:24:50 GMT -5
^^^ actually that's not how carburetors work; try a search on "volumetric efficiency" if you want to understand it better. It is completely possible that a 650 CFM (or even smaller) carb can be tuned razor sharp on a 460 engine in the typical RPM's for a derby application. If it is running lean it's a matter of making jetting changes, not bolting on bigger airflow carbs. go back to carb school dude, you abviously have no clue! changing jets just make it richer, has nothing at all to do with cfm. A 460 needs cfm not rich gas air mix. Last 460 I had prosystems carburators build a carb for me, engine was a stock 460 bored .030 over with very, very small cam, .500 lift and 215 duration at 050, flat top pistons, 2.25 and 1.75 valves. He sent me a 1,000 hp dp carb with 80 and 85 jets in it with 50cc accelerator pumps on both ends. Carb bolted right on and was perfect. I pulled carb one time for a guy arguing same point you are. We installed a 650 holley dp and i let him mess with it and at about 3,500 rpm's it was done and didn't idle worth a crap. I laughed in his face and put my 1,000 cfm holley back on and went on.
|
|
dm440c
Feature Winner
derby drivers against drama- there's no crying in demo derby!
Posts: 2,824
|
Post by dm440c on Apr 16, 2014 10:44:42 GMT -5
no need for insults.
Your statement that "changing jets just make it richer, has nothing at all to do with cfm" is just plain nonsensical. Now, that is not an insult, it's the truth. OK, I'll take the bait here. Let's "go back to carb school" as you suggested.
What is the relationship between intake system airflow, engine displacement, and RPM? Surely a carb whiz doesn't just make wild guesses when he is selecting a carburetor...
What does the CFM rating of a carburetor mean? Not the acronym, but what does it mean in terms of function?
What is the stoichiometric ratio, and how does that relate to carburetor tuning?
That's enough for starters. A guy who insults the intelligence of others on the subject of carburetor selection and tuning should be able to answer those without looking it up first.
|
|
|
Post by metalman187x on Apr 16, 2014 22:05:05 GMT -5
the 390 I have came out of a 65 custom and is BONE stock (I even flipped the manifolds) but it runs great and doesn't miss a beat im just worried more about the mounting situation. there is a big hole in the firewall from the previous owner who had a 350 in it so I don't want any chance of having a motor in my lap. the only problem with my 318 is it is in another car that will run before the wagon and if anything happens to it im stuck with the 390 so I guess ill take it out and build some mounts and see how everything works out. does anyone out there have a mount design that doesn't include the rubber pieces? the ones on my 390 are completely shot and I don't see a whole lot to bolt to on the bottom of the block for home made mounts. I think I'm leaning more towards the 318 so I can build some mounts for the 390 and test it in a car I'm not as worried about getting owned in if the motor shits out but im still un decided. I chased that wagon for years and then spent a couple more building it so I want the most reliable motor to go in it. also, which motor would respond to the 4:11 ratio in my 9 inch? I know the 4:11 ratio really wakes my 318 up so im kinda curious on the 390 and was wondering if anyone has ran that motor and gear ratio combo. thanks for all your input guys.
|
|
|
Post by aoldfart on Apr 17, 2014 3:36:03 GMT -5
I took the stock mounts, drilled thru them, and bolted them together. Never had one break.
Use large flat washers for the bolts to hold the mounts together. Or use a couple sections of steel square tubing to make the mounts. Cover the hole in the firewall with sheet metal. Are you allowed to weld/bolt flat iron, to the frame/heads and or the block? You can also use chain to add as a backup, if any mounts break. I only used the stock gearing, so don't know how the 4:11's will work for you.
Steve
|
|
|
Post by metalman187x on Apr 17, 2014 10:47:33 GMT -5
thanks for the input steve. I have the firewall welded back up as much as I want that way I can still reach in and mess with the motor if I have to I just don't want any chance of it jumping out and breaking my welds.
|
|
|
Post by rpmotorsports on Apr 26, 2014 16:58:51 GMT -5
No need to sweat the 390, great motor. You won't be disappointed.
Have had good luck with the 460 as well. Most any motor will run well provided it is tuned properly.
|
|
|
Post by TeamMASS#16 on Oct 26, 2015 17:22:42 GMT -5
Ive got a 460 from a 76 LTD. and i was wondering if i should ditch the duraspark and convert to HEI. Would a Holley 750 Double Pumper be a good carb to put on this engine. And what size header pipe should I consider using to get good exhaust flow
|
|
|
Post by moose313 on Apr 5, 2016 23:14:43 GMT -5
Ive got a 460 from a 76 LTD. and i was wondering if i should ditch the duraspark and convert to HEI. Would a Holley 750 Double Pumper be a good carb to put on this engine. And what size header pipe should I consider using to get good exhaust flow I converted to HEI. Only reason is I couldn't get the DuraSpark to even work. Best thing I've done for the motor so far. As for your other questions I'm not sure. Any timing tips for a stock 460? All stock except HEI dizzy and some DEC headers.
|
|
|
Post by TeamMASS#16 on Apr 6, 2016 9:04:30 GMT -5
Ive got a 460 from a 76 LTD. and i was wondering if i should ditch the duraspark and convert to HEI. Would a Holley 750 Double Pumper be a good carb to put on this engine. And what size header pipe should I consider using to get good exhaust flow I converted to HEI. Only reason is I couldn't get the DuraSpark to even work. Best thing I've done for the motor so far. As for your other questions I'm not sure. Any timing tips for a stock 460? All stock except HEI dizzy and some DEC headers. Thanks for the info
|
|
|
Post by koble927 on Apr 17, 2016 12:35:56 GMT -5
What are you guys setting your timing and idle at with these
|
|
|
Post by moose313 on Apr 18, 2016 12:35:17 GMT -5
What are you guys setting your timing and idle at with these That's some info I'd like too.
|
|
|
Post by becklerb52 on May 2, 2016 20:49:54 GMT -5
I need help identifing a 1976 ford motor in my truck i belive ita a 390 not positive though only tag i can find on it is a brass one rivited below the alt and it has RM-2 153905 then on the driver side it has 105 reverse cast number those were all i could find the motor ia still in the truck but dirty as hell i need to find a transmisson for it blew a nice hole when it hit the firewall i know its a c6 and i belive i need a certain one? Not the smartest about motors any help would be apreciated thanks
|
|
|
Post by fordpowerforever on May 3, 2016 12:17:30 GMT -5
does it have the intake manifold going underneathe the valve covers? if yes then its a 360 or 390 FE family motor. most likely option in 1976
|
|
|
Post by becklerb52 on May 3, 2016 18:20:54 GMT -5
Do the 360 and 390 have the same transmission bolt pattern?
|
|
|
Post by fordpowerforever on May 4, 2016 11:18:33 GMT -5
yes all FE family motors share the same trans bolt pattern 352,360,390,427,428 and the few other odd ball ones.
|
|