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440 Source pushrod clearancing

Posted By: Cab_Burge

440 Source pushrod clearancing - 07/29/11 09:20 PM

I finished grinding on the 440 source heads that I'm putting on a customers 383 bracket motor, they have a set of Crane 1.6 ratio ductile iron rockers and 3/8 pushrods. Picture one is of #4 intake port wall, some of them required more grinding than other ones All of the intake rockers required shimmimg away from the stock rocker shaft holdowns My message is make sure your pushrods clear all the way down, at closed and opened

Attached picture 6752846-MVC-015S.JPG
Posted By: Cab_Burge

Re: 440 Source pushrod clearancing - 07/29/11 09:24 PM

Picture two is of the #2 intake port wall. I didn't think of taking a picture of them before starting, for those that don't have a set yet, sorry. BTW, I didn't have to grind on my Eddy RPM at all with 1.5 rockers and I did have to grind on one intake port wall on another set that has the Harland Sharp 1.6 rockers

Attached picture 6752851-MVC-016S.JPG
Posted By: Mick70RR

Re: 440 Source pushrod clearancing - 07/29/11 10:10 PM

Just done the same on mine. Here's a picture before I started.

Attached picture 6752902-Pushrodslot.JPG
Posted By: AAR-B4

Re: 440 Source pushrod clearancing - 07/30/11 12:30 AM

Just as a warning; the pushrod clearancing limits any porting you may want to in that area.
Posted By: Mick70RR

Re: 440 Source pushrod clearancing - 07/30/11 10:02 PM

My heads were CNC ported by MCH so I was worried I would break through the port wall. It's a shame the push rod holes couldn't have been opened up while the heads were at MCH.
Posted By: Thor500

Re: 440 Source pushrod clearancing - 07/30/11 10:06 PM

Quote:

My heads were CNC ported by MCH so I was worried I would break through the port wall. It's a shame the push rod holes couldn't have been opened up while the heads were at MCH.




I agree, do they check guide clearence and such or just port and slap them back together?
Posted By: Mick70RR

Re: 440 Source pushrod clearancing - 07/30/11 10:35 PM

After porting the guide clearance is checked, valve spring installed height is checked and shimmed if necessary and he does a multi angle valve job. They should be ready to bolt on, unless you are using 3/8" push rods.
Posted By: dodger mope

Re: 440 Source pushrod clearancing - 07/30/11 10:58 PM

My heads were CNC ported by MCH so I was worried I would break through the port wall. It's a shame the push rod holes couldn't have been opened up while the heads were at MCH.


To clearance push rods I would think MCH would need the block,rocker arms,cam,lifters and push rods. At times there isnt much material to work with.
Posted By: 1967Valiant

Re: 440 Source pushrod clearancing - 07/31/11 12:12 AM

I had cnc ported stealths put on my motor. It has 1.5 prw rockers on it. I know the builder said they were close with 3/8 push rods, but didnt hit guess I better check them myself.
Posted By: Cab_Burge

Re: 440 Source pushrod clearancing - 07/31/11 01:51 AM

Quote:

Just as a warning; the pushrod clearancing limits any porting you may want to in that area.


I didn't try to remove material towards the port I removed material between the valve and the area they had already machine for pushrod clearances as well as I laid the already machined shoulder area over to clear the pushrods moving towards the valves due to the 1.6 ratio rockers moving the pushrods towards the rocker shafts some I also moved the rockers over on the shafts between .015 and .075 to help clear the pushrods and heads as well as centering the rocker pads over the valve centers If you want bigger ports buy a set of 440-1 and use the offset roller rockers to help align the pushrods off center with the offset intake rocker arms
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