Mechanical fuel pump on a roller cammed 360?

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Kern Dog

Kern Dog

Build your car to handle.
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I have no experience with the 318s and 360s once they were fitted with roller cams and lifters. I have even less experience with the Magnum series engines.
A friend may be willing to part with an '89 360 that had a roller cam but he swapped in a hydraulic flat tappet setup in it.
I'd like to use it but put a roller setup back in place for the reduced risk of cam and lifter failures. I thought I heard that these engines had no provision to drive a mechanical fuel pump.
I like mechanical pumps and would want to use one. What needs to be done to allow this? The eccentric on the end of the cam usually fits over the cam sprocket with a Woodruff key to index it. I thought the roller cams were not grooved for that Woodruff key.
 
here you are sir.



ETA: idk why the link didn't resolve, but it's a spacer specifically designed for the roller cam snout and the eccentric from hughes.

second edit: there's long snout roller cams that *do* have the provision for a pump eccentric. these are typically in the early roller motors and won't fit with the magnum front cover. so basically what i'm saying is open it up and have a look see before splashing 60 bones on something ya don't need.
 
Make sure the cam you use has the rocker shaft oil feed holes drilled in the #4(?) cam journal as well. Magnum cams do not have these holes.
 
Roller LAs (from the factory) all had long snout cams. Some passcar rollers (non-TBI, with feedback carbs- usually found in Fifth Avenues and the like) already had mechanical fuel pumps. The later '88-'91/'92 TBI motors (found in trucks and vans) used an electric fuel pump in the tank and did not have the mechanical pump, however they still retained the long nose cam. The timing cover either used a block-off plate or did not have the pump boss finish machined, and did not have an eccentric installed on the cam- there was a special deeper cam washer used to make up the difference in depth with the eccentric deleted. Use a standard LA cam bolt washer and the eccentric is a bolt-on; either remove the fuel pump block-off plate or finish opening up the fuel pump boss on the timing cover- depending which you have- and you're good to go (or swap covers if you don't feel like opening up the boss on the TBI cover).
Magnums all had short snout cams and need the Hughes adapter and a timing cover/water pump/accessory drive swap if you want to use a mechanical pump.
Side note: Don't try to use a Magnum cam in a roller LA- it will fit and run, but it's lobes are ground for the Magnum's 1.6:1 rocker ratio and there will be a resultant power loss when run with the LA's 1.5:1 rockers.
Conversely, a factory LA roller cam used in a Magnum can give a nice little low-cost power boost with the Mag's higher ratio rockers.
 
I think you’ll be fine with your friends ‘89 cam Kern for all the points and reasons listed above.

I have the magnum motor so HAD to use an electric fuel pump. I didn’t necessarily want to to buy and EFI tank and install kit with bypass regulator BUT did and am actually kind of glad now as if I ever want to explore a tbi based (or other) fuel injection (aka sniper or fi-tech etc) I can with out having to worry about buying the pump/tank etc at that time reducing the out of pocket shock…. Will only have to pay for the tbi unit.

Only reason why I mention this is because as a hot rodder we seem to get bored and like to try new **** over time so perhaps this is something you may want to consider for yourself. And if you did then the fuel pump drive eccentric accommodations of a cam would be a moot point and you could choose whichever cam you want right now.

One big plus of having the electric pump set up in my carbureted magnum is immediate starts even after sitting for a long time and also seems to start better when hot too. The prime of an electric setup is nice. The bypass regulator and return system keeps the fuel cooler too….

Big down side of the internal tank pump set up is cost though…. When I did it I had to buy a new tank as mine was leaking and bashed up so the upgrade cost to go from regular to EFI tank wasn’t that much more and it eliminated the cost of a hi-po mechanical pump too. If I had a good tank at the time I may have opted for the inferior external electric pump and el cheapador Holley regulator….

I wonder if tbi fuel injection systems decrease emissions too? Not that I care too much but you being in California might end up getting screwed if they start demanding minimum emissions requirements. Not sure maybe they already do? I don’t know anything about that, in alberta we don’t have smog testing and requirements like I hear of and some states do?

I need to win the lotto! lol.

good luck with your 360 swap!
 
I had forgotten that Mags use higher ratio rockers

I don't know why you guys continue to argue with mechanical pumps. I doubt there are truly high quality pumps being made, so failure is probably higher, and diluting the oil is an issue. Then there's the "new gas" which is just plain worse for fuel boil/ vapor lock. Having a rear mount pump is an advantage.
 
4mulas said:
I think you’ll be fine with your friends ‘89 cam Kern for all the points and reasons listed above.
Click to expand...
That's the issue- it doesn't have the '89 cam, it was replaced with a hydraulic flat tappet but he wants to switch back.
 
I'd run what ya got, cuz IMO, with the right oil, lobe-failure is a non-issue, or daymn close to it. My 367 has had the same FTH cam in it since 2004, My guess is close to 100,000 miles, it has enough spring pressure to run well over 7500 rpm.
I've been waiting over a decade for it to fail, so that I can put a slightly smaller cam in it.....
 
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