[richarddickey2]

ok first let me fill you in its a 1986 truck 460 bone stock. has a manual. this truck is a f-250. this truck will be a daily.. but i want to use it as a calling card so to speak. the truck will be used as a mobile mechanic truck. I,m looking at a Comp Thumper cam. I'm not wanting race power. more just for the radical idle. the truck has air and power brakes. would this be too much cam? the truck will mainly operate in the 2000-3000 rpm range due to a butt load of highway. if this cam is too radical any suggestions on what i want ? my main goal is a loapy idle. the low gears of the rear and granny low will compensate for the duration of the cam. Plans are also a rpm dual plane air gap headers and roller rockers. rotating assembly will be stock. and stock heads.

 

[galaxiex]

You need to watch this video...

 

[BrewBoy]

Great explanation of head flow and choosing the right cam lift. But I'm watching the explanation of valve spring pressure, and I'm having an issue. He states that all 16 springs are exerting 300 lbs. of pressure each against the crank at the same time. But all 16 springs aren't compressed at the same time, right?

 

[rickyracer1983]

You have anywhere from seat pressure say 100# to open pressure, say 300#. All different up and down the cam.

 

[extech]

so at any one time there is at least 300# spring pressure applied to the cam

 

[rickyracer1983]

so at any one time there is at least 300# spring pressure applied to the cam

All along the cam your min and max spring pressure is applied. Even when it's not running. This is why some hyd lifters bleed down, then have to be pumped back up on start up.

 

[rickyracer1983]

Since your orginal opening was about Max Valve lift and you listed a 68 460, those heads will go .550" unless they have the exhaust bump in them. Then I wouldn't go over .500". Better place to ask these questions, 460ford.com. Find "The Mad Porter". He knows more then anyone and can give you the best info anyone ever can.

 

[JeffB2]

It sounds like you would be better off getting a custom grind instead of an off the shelf "fits all" cam I suggest you call these guys and talk to them,I think you will like the prices too. Camshaft | Engine Cam | Camshaft Repair

 

[My427stang]

I also recommend a custom grind. I would not go Thumpr, they are sloppy at low RPM and part throttle, get horrible mileage due to all the overlap, you will have NO power brakes, but they do sound cool.

In my own truck, 461 FE, I went with a custom 280/286 230/236, .580 lift, 112 LSA on 106, it made 490HP at 5000 RPM and 554 ft lbs of torque. I'd probably shop for a lobe with .530-ish lift for yours if it doesn't havce aftermarket pistons with deep reliefs though. Other than lift, pretty good match for yours and makes vacuum for brakes, idles at 750 with a bit of chop with EFI, idled at 825 ish with a carb

Don't forget though, you will need a valve spring swap except for all but the mildest of cams. PM me if you need more cam info, I order customs all the time from various suppliers.

No interest in hyd roller? Cost is higher, but man, more selection and no worries about break in or daily use