Fuel pump Questions for Dany's Magnum swap.

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motorpirate

serial mopar owner
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So. all the tire failures this month have put a big dent in the race car budget, but we still want to try to move forward.
Our original plan was for a cam swap, but i think that's out until next season.
That leaves us with a "short snout" original Magnum cam. And no way to put an eccentric for a mechanical pump on it.
Anyone here using this Mancini Racing deal successfully?Hughes Engines Camshaft Bolt & Washer

We are going to "disguise" the Magnum as a Commando 273 and I would prefer to use a mechanical pump just to keep it simple, but....

Is the Mancini conversion dependable? don't want to pull the timing cover on the side of the interstate..

I'm sure a stock pump will support the 300 HP i'm guessing the stock cam is good for but will it support the 380 I hope to get later with the cam change?Voodoo Hydraulic Roller Cam - Chrysler 273-360 (W/ Long Snout) 264/270 - Lunati Power
It looks done by 5500 RPM.

If i need more pump what about this?Carter M6270: Strip Super Fuel Pump Small Block Chrysler/Mopar 273-360 | JEGS

Or, at that point do we go electric? I mean $50 for the eccentric conversion. and $100 for the pump maybe this is cheaper in the long run? 1https://www.jegs.com/i/Carter/180/M6270/10002/-1?CAWELAID=1710849641&CAGPSPN=pla&CAAGID=15769068431&CATCI=aud-194566579511:pla-177240442871&CATARGETID=230006180003468500&cadevice=c&jegspromo=thirdparty&gclid=Cj0KCQjw45_bBRD_ARIsAJ6wUXQllox0RtqljmHk7VjpGsX-VNpQJk6zwnGhPkw8lOkLk_MQjPZweWIaAhkTEALw_wcB

And one last question, at what HP level do we need to ditch the 5/16 fuel line for 3/8?

Thanks so much guys!!
 
  • I've gone 12's off of a mechanical fuel pump and factory 5/16 fuel line from the factory tank with no issues.
  • I've never tried the hughes eccentric (or magnum swap for that matter). Owned tons of LA's and lots of magnums,but never swapped. Going to, though, at some point. Have a 318 magnum/eddy RPM intake sitting in storage.
  • If you can get a '89 - 91 LA360 cam, they will have the fuel pump snout. They are roller cams, so they work and you'll gain about .030 lift as they are ground for the 1.5 rocker instead of the magnum 1.6. I have this cam for my "eventual swap".
 
318willrun said:
  • I've gone 12's off of a mechanical fuel pump and factory 5/16 fuel line from the factory tank with no issues.
  • I've never tried the hughes eccentric (or magnum swap for that matter). Owned tons of LA's and lots of magnums,but never swapped. Going to, though, at some point. Have a 318 magnum/eddy RPM intake sitting in storage.
  • If you can get a '89 - 91 LA360 cam, they will have the fuel pump snout. They are roller cams, so they work and you'll gain about .030 lift as they are ground for the 1.5 rocker instead of the magnum 1.6. I have this cam for my "eventual swap".
Click to expand...
Stock mechanical pump?
The Hughes eccentric I would view as temporary ( one season?) as I REALLY want to cam this thing!!
But I told Dany, even the stock cammed Magnum is a big HP improvement over the 2bbl 273...
 
motorpirate said:
Stock mechanical pump?
The Hughes eccentric I would view as temporary ( one season?) as I REALLY want to cam this thing!!
But I told Dany, even the stock cammed Magnum is a big HP improvement over the 2bbl 273...
Click to expand...
  • I did put a Holley mechanical pump on "just in case", but it wasn't necessary. It didn't change a thing. I've had so many combination of "very mild" street cars that easily did over 100 mph in the 1/4, often they were swapped slant six cars still running the factory slant six fuel lines.
  • Yes, a stock magnum would be a huge gain over a 273 2bbl. In fact, a stock LA 318 2bbl would be a nice gain. I've gone 15.9's with a bone stock LA318 2bbl, stock manifolds, 2.94 gears in a b-body.
 
Probably overkill at this point, but I run a carter mechanical with a holly red electric with 3/8” line. Super stable fuel supply. I ran a holley blue and a holley black at different times using the supplied regulators. Always had issues,looking back I’m sure it was the cheap regulator, but my current combination just flat out works and helps with priming the carb if it sits and the fuel evaporates. Also if the electric dies my car will run off the mechanical alone. Only to 4000rpm, but would get you home.
 
I have a comp XR280HR-10 roller with less than an hour of run time with the long snout, cheap, look the specs up if it will work for you send me a PM.
 
I have used a couple of those Hughes adapters. One has been on my brothers car with a Mopar Performance camshaft for around ten years now with lots of street miles. I forget which fuel pump we put on it, and I forget the cam specs.
I filed the key and adapter until everything fit snug, then during final assembly I used red loctite on the cam bolt threads. Never came loose.
Stock 5/16 fuel line.
 
sireland67 said:
I have a comp XR280HR-10 roller with less than an hour of run time with the long snout, cheap, look the specs up if it will work for you send me a PM.
Click to expand...
Thanks, but it's too big for what we have going on (stock converter,3.55's and no headers)
 
I run the carter 6270 with a Summit regulator 6.5 psi, 5/16" pickup bent to tank bottom no sock, 3/8" fuel line to pump, 1/2" to 1 qt spin on filter, regulator and carb tee. With the same setup and stock pump, my AFR fluctuated from run to run on the top end. The 6270 pump solved the problem for me on my 340/400hp.
 
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