I have plans for TT on my cobra. Right now I am getting ready to get my heads ported and polished. Also I am upgrading my valvetrain. I am thinking about 1 mm oversized valve. What benefits/ negatives will be seen from doing oversized valves? Will I gain anything on the top end? I am planning on getting new valves anyway, so I might as well pay the extra for oversized ones if there is a benefit.
1mm Oversized Valves
- Thread starter cgbills
- Start date
do they fit the stock valve seats?
LS1PUSSOUT
Banned
im pretty sure you cant use oversized valves unless your block is bored at least .020 over because the valves come so close to the cylinder walls....
can anyone confirm this?
To be honest I'm not sure, but I do have the oversized valves and a .020 over block. No problems here.
Same here.
is it still the case with a teskid block? i would think it was
Bores are the same so yes. Unless your running darton sleeves or something.
There is no truth to this, a 1mm oversize valve can be used on a std bore block with zero clearance issues, we have been selling/using them this way for over 10 years. The clearance issues are generally on the 2V heads. A 1mm oversize intake valve still has .080 clearance (at its closest point) between the cylinder and valve @.200 lift, (keep in mind the valve only moves further away from the cylinder as it opens due to the factory valve angle)
Of course the exhaust valve can be increased as large as 2mm over factory, case in point the Ford GT heads use a 32mm valve from the factory (aprox. 2mm larger than a DOHC Cobra (which comes factory with a 30mm)
Hope this info helps anyone considering this upgrade!
MMR
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