304 performance question

[72scoutII304]

Does anyone make any performance parts for the 304? I'm just looking for a little bit bigger cam so I'll get more of that lopped exhaust I saw scouts parts have some but I'm not sure about them and I've searched this a lot and that's the only place with anything so far.

 

[Robert Kenney]

cam & lifters - IH Parts America : International Scout parts

Buy them right here.

 

[72scoutII304]

Thanks I like the price here a lot better then scoutparts.com their cams was like $300

 

[Scout-It-Out]

Just a bit of fyi, "lopy" idle cams typically have less low end torque than stock. My Dad has a comp cams with "noticeable idle" I think they call it. It really runs great about 65mph! Off idle isn't bad. I guess just check your cam specs and see if it looks good for your driving style.

 

[Robert Kenney]

Ok some cam basics. The typical IH cams on the market that would lope, have way to much duration to use stock compression and still be usefull. The formula is basicaly 216 deg at .050 and 106-108 lobe centers. The tight lobe center will preserve cylinder pressure and allow enough exhaust reversion because of the large overlap to have a nice lope. It will be a tad lazy but power will come on early. Power will be big and peaky.
IHPA can have a cam like this ground fairly easy should you choose this direction.
My personal opinion is that a lopy IH just to hear it is a total waste of time.

 

[Bill Bennett]

With the cam 'overlap' lowering the compression pressure, how much should the heads or block be shaved to allow for the thicker 'aftermarket' head gaskets and the loss of compression pressure from the cam, to get close to original cranking pressures with full height pistons and bored + 40/1000 ?

 

[Robert Kenney]

Hi bill, actually increasing overlap in itsself will not lower cranking cylinder pressures. By tightening lobe centerlines the intake closes earlier which is on the compression stroke where the pressure is bleed off. So on a given cam lobe profile, increasing overlap will increase cranking pressure
for intake closing angle at .050, I use .5 in compression ratio for 4 degrees later closing point. It is very subject to other variable like valve sealing diameter and valve velocity.