My home inspection of Speedmaster heads
And I thought the point of buying these was to not spend as much as, or very close to, what you’d have into a set of TF’s.
The throat diameter is 1.890, which is 93% of the 2.02 valve.
Way too big for the lift range most everyone using these will be running.
They cut right up to the 45 on the vj.
Maybe PBR can measure the throat of the unported head.
My guess is, it’s bigger than it should be as well.
They want the porting to be “pretty”, with a minimum of drop outs...... Imo they’re porting below the seats for appearance...... not for flow.
In order to have the throat percentage be more in line with the valve diameter and lifts most will run with these heads you’d need to run a 2.08 valve.
Then you start to run into valve shrouding issues....... more $$$ to fix.
For what many buying these heads are looking to do....... for the $$$ they spent on the CNC version over the bare head, I think you’d be better off buying the bare heads, have the seats cut for 2.055/1.60 valves, and the bowls blended.
My guess is that would have you ahead of the ootb cnc version, flow wise, through about .550 lift....... for similar $$$.
And I thought the point of buying these was to not spend as much as, or very close to, what you’d have into a set of TF’s.
The throat diameter is 1.890, which is 93% of the 2.02 valve.
Way too big for the lift range most everyone using these will be running.
They cut right up to the 45 on the vj.
Maybe PBR can measure the throat of the unported head.
My guess is, it’s bigger than it should be as well.
They want the porting to be “pretty”, with a minimum of drop outs...... Imo they’re porting below the seats for appearance...... not for flow.
In order to have the throat percentage be more in line with the valve diameter and lifts most will run with these heads you’d need to run a 2.08 valve.
Then you start to run into valve shrouding issues....... more $$$ to fix.
For what many buying these heads are looking to do....... for the $$$ they spent on the CNC version over the bare head, I think you’d be better off buying the bare heads, have the seats cut for 2.055/1.60 valves, and the bowls blended.
My guess is that would have you ahead of the ootb cnc version, flow wise, through about .550 lift....... for similar $$$.
