Flathead info

S

silvalms01

Member
I have these two flatheads i need to do something with. One is a 4 1/8 x 3 3/8 short block. The other is a 4 x 3 3/8 that is apart. I think the complete one is factory relieved and the other is hand done. The lifter bosses are drilled on both blocks. The complete one has a old Weber cam. The complete motor shows a pic with a valve open. Could anyone give thier opinion on the relief work? Are the lifter boss holes there to hold the lifter when adj or for lube? And last any thought on can lift by looking at the pic? [Wondering if it looks like a good amount of lift] Thanks,Pete
 

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The factory relives iv seen are just strait cuts between the valves and bore (no nice curve) the other looks like they smoothed the transition only.

Yes holes are for holding the lifters with a pin punch or ? Then adjust.


What’s the plan? Are they going away?
 
Holes in lifter bosses are for holding the lifters for adjustment. Old cams often had unfriendly ramp design. Only way to find out is to try it.
 
I concur that the reliefs are not factory, as factory reliefs are a perfect straight line cut from valve chamber to the bore where possible, leaving out the chamber extremes. As flatjack9 stated, the holes are drilled way to high. They need be drilled as low as possible, or they will not allow engaging the lifter slots with high lift cams. High lift cams have a smaller base circle, so the lifters sit lower.
 
If these blocks don't have any cracks, a good clean up and rebuild should make them ready to please any Flathead owner. Biggest problem will be piston clearence. The block with the relief might have a head gasket problem. Check em both before you spend any money on them. Weber made some great cams.
 
This is an excellent track cam. However it's a little hard on the valve train for a street. Allot of guys run them.
 
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