Flow bench results for CNC ported Pro comp heads

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Jax

Jax

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After damaging one side of the heads, took the one that remain " intact " to the flow bench in order to have an idea on current flow capacity. This was done to make sure that whatever heads set up I purchased will be equal or exceed the current head flow capabilities.

For our surprise, these head only flow as following.

Intake ( cfm )Exhaust (cfm )
0.100​
71​
67​
0.200​
129​
110​
0.300​
175​
135​
0.400​
220​
160​
0.500​
231​
174​
0.600​
239​
181​
 
If that’s the case, I’ll take a stab at it and say, no short side work, not much in the bowl, common wall not touched, rest of the port was given a clean up.
 
Yep !!Besides paying for a service that I didn't receive from a former forum Abodies well known member, the head dropped a valve seat causing losing almost 80 % of the engine.
 
Jax said:
Yep !!Besides paying for a service that I didn't receive from a former forum Abodies well known member, the head dropped a valve seat causing losing almost 80 % of the engine.
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The whole situation is unfortunate, but I think valve train geometry is what killed that head. What hack shop built that?
 
replicaracer43 said:
The whole situation is unfortunate, but I think valve train geometry is what killed that head. What hack shop built that?
Click to expand...
Check your PM ..... For clarity purposes... is no one active on the forum or current active business.
 
Those heads need a 2.08 intake valve because of the already large throat set by the cnc porting. I just did a set for an engine we're building, with our valve job, chamber touchup, 2.08 intake valve, ours go 277cfm at .500 and 290cfm at .600 lift. They are a bit unstable after .600 lift but only dropped a couple of cfm...untouched ports other than the valve job, tootsie rolled the short turn (there is a sharp edge on top of it that needs knocked down) and chamber unshrouding.
 
Brian Hafliger said:
Those heads need a 2.08 intake valve because of the already large throat set by the cnc porting. I just did a set for an engine we're building, with our valve job, chamber touchup, 2.08 intake valve, ours go 277cfm at .500 and 290cfm at .600 lift. They are a bit unstable after .600 lift but only dropped a couple of cfm...untouched ports other than the valve job, tootsie rolled the short turn (there is a sharp edge on top of it that needs knocked down) and chamber unshrouding.
Click to expand...
Mine was build with 2.055 intake valves and 1.62 exhaust valves
 
With a 1.6 ex. and my valve job, nothing else...198cfm at .400, 223 at .500, and 234 at .600 using a short tube as I always do.
 
Who in their right mind still
Uses the “Pro Comp” branded name. That the name that has had people running away for years. I had to Google it and found this. I had to give myself CPR.

25C2BE97-BF0B-433C-8CB5-4C738F7437B5.png
 
Jax said:
Check your PM ..... For clarity purposes... is no one active on the forum or current active business.
Click to expand...
Thanks for the message. What did the "dyno sheet" from this engine say?
 
replicaracer43 said:
Thanks for the message. What did the "dyno sheet" from this engine say?
Click to expand...
Well, we don't have an engine dyno locally and we never took the car on a dyno.
But we ran the best 10.25 @ 129 mph in my 2900 lbs conquest with me in. On an online calculator this throw about 525 to 550 hp on the motor
 
Jax said:
Well, we don't have an engine dyno locally and we never took the car on a dyno.
But we ran the best 10.25 @ 129 mph in my 2900 lbs conquest with me in. On an online calculator this throw about 525 to 550 hp on the motor
Click to expand...


That’s a pretty nice ET for the flow numbers you gave us. Not great but not bad either. I’m not sure how did your heads but is there any chance you had a valve job done? If it’s who I’m thinking of I’m pretty sure this guy used let’s say non standard valve angles. And if a more normal valve job was cut and already big throat may be bigger yet with your 2.055 valve. Just thinking outside the box here.
 
pittsburghracer said:
That’s a pretty nice ET for the flow numbers you gave us. Not great but not bad either. I’m not sure how did your heads but is there any chance you had a valve job done? If it’s who I’m thinking of I’m pretty sure this guy used let’s say non standard valve angles. And if a more normal valve job was cut and already big throat may be bigger yet with your 2.055 valve. Just thinking outside the box here.
Click to expand...
I will post some pictures of the head chambers and valves later.
 
Those flow numbers are uncharacteristicly low.

Was a suitable radiused air entry used?
 
The heads I just prepped similar to yours just made 553HP on a 408 with 10.35:1 compression. Solid FT cam, 850 carb.

 
Jax said:
After damaging one side of the heads, took the one that remain " intact " to the flow bench in order to have an idea on current flow capacity. This was done to make sure that whatever heads set up I purchased will be equal or exceed the current head flow capabilities.

For our surprise, these head only flow as following.

Intake ( cfm )Exhaust (cfm )
0.100​
71​
67​
0.200​
129​
110​
0.300​
175​
135​
0.400​
220​
160​
0.500​
231​
174​
0.600​
239​
181​
Click to expand...
That sucks.
Id say based on the .100/.200 that's @28"
 
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