bore size on sohc heads

[hbstang]

any gains on running a 4.280 bore over a 4.250 bore with sohc heads?also,intake valves 2.250 vs 2.350?not a race engine , street and some strip time.

[blykins]

The valve size will depend on the brand of cylinder head and what size the throat already is. 

[pbf777]

         As with the S.O.H.C. and the valves being angled toward the center of the cylinder and as the valves are opening they're moving away from the cylinder walls, probably not enough to justify chasing.   

         Scott.

[hbstang]

took some digging but found this here.intake valve hitting sleeve?not my engine,a few years back.coon heads with 4.250 bore.so not sure why this happen to him,but i have to rethink my small bore on my pond block?


OK guys....  took the head off and surprise surprise.....  The intake valve nicked the lip of the cylinder!  Didnt touch the piston and wasnt stuck in the valve guide.....

So, with a little dremmel action and a diamond cone...  this problem will be overcome!  See photos below.  You can see a tiny witness mark on the lip.....  Just barely knicked it.

[Barry_R]

took some digging but found this here.intake valve hitting sleeve?not my engine,a few years back.coon heads with 4.250 bore.so not sure why this happen to him,but i have to rethink my small bore on my pond block?


OK guys....  took the head off and surprise surprise.....  The intake valve nicked the lip of the cylinder!  Didnt touch the piston and wasnt stuck in the valve guide.....

So, with a little dremmel action and a diamond cone...  this problem will be overcome!  See photos below.  You can see a tiny witness mark on the lip.....  Just barely knicked it.

Yep.
Now check the head gasket.
Some bore size Cometic gaskets will snag the valve as well.

[hbstang]

talked to chris whitney and he said with the 2.350 intake valve you have to notch the bore or use a 2.300 inch valve.i guess the 2.250 will clear ok.ok,with that said,my head gaskets are cometic with a 4.400 bore.