I pulled my heads today and I'm going to go ahead and do my own mild porting job in my garage. Doesn't seem like rocket science and I don't expect to build a race engine, just to get whatever cheap performance upgrade I can. Any good advice before I start?
Head Porting do's and don'ts
- Thread starter YEEE85
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BEATAV8
The Engine Whisperer
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bang for the buck is in the bowls
Stu Klomann
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I have a friend locally that did this years ago he just took his time and was patient with grinding
Perform an Advanced Search for porting or port work by forum member Mike T.
TIMINATOR
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A multi angle valvejob by a GOOD shop makes as much or more power as a GOOD backyard port job when used with a stock cam.
Below about .200" lift, the flow has almost nothing to do with the port, its all about the valvejob (number of angles, angles themselves, valve underhead shape, back cuts, if any, and seat width.)
Valve opening and closing rates are slowest just off of the seat (and the valve is there twice, on opening and closing) ramp rates are fastest at and near max lift and only there once.
The port doesn't end at the valve seat.
Turbo buick chambers suck.
If you don't own a flowbench (minimum flow 300 cfm) and know how to use it, you can do more damage in 5 minutes with a die grinder than can usually be gotten back.
Stock heads are rare and expensive.
The finished ports should be exactly the same.
On almost every backyard port job I have seen, it's easy to see which port was done first, and last,
not the same amount of grinding.
Most backyard porting flows less than stock.
Fuel injected head port balance is more critical than on carbed engines.
Injected turbo motors even more so.
Just some random observations from a guy that lived on a flow bench for 50 years in the business.
Good luck!
TIMINATOR
Below about .200" lift, the flow has almost nothing to do with the port, its all about the valvejob (number of angles, angles themselves, valve underhead shape, back cuts, if any, and seat width.)
Valve opening and closing rates are slowest just off of the seat (and the valve is there twice, on opening and closing) ramp rates are fastest at and near max lift and only there once.
The port doesn't end at the valve seat.
Turbo buick chambers suck.
If you don't own a flowbench (minimum flow 300 cfm) and know how to use it, you can do more damage in 5 minutes with a die grinder than can usually be gotten back.
Stock heads are rare and expensive.
The finished ports should be exactly the same.
On almost every backyard port job I have seen, it's easy to see which port was done first, and last,
not the same amount of grinding.
Most backyard porting flows less than stock.
Fuel injected head port balance is more critical than on carbed engines.
Injected turbo motors even more so.
Just some random observations from a guy that lived on a flow bench for 50 years in the business.
Good luck!
TIMINATOR
TIMINATOR
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For an experienced porter, yes.
You may hurt the flow or cause the guide boss to eventually crack, or both. You might want to price and check availability before you make up your mind.
TIMINATOR
You may hurt the flow or cause the guide boss to eventually crack, or both. You might want to price and check availability before you make up your mind.
TIMINATOR
TIMINATOR
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- Jan 26, 2020
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I use T/A race headers as the pass side street header is poop. and not much better than the stock one and has the same serious imbalance on cyl. #6. I also port the transitions and welds too.
More difference than porting and the race headers also raise the convertor stall a bit too.
TIMINATOR
More difference than porting and the race headers also raise the convertor stall a bit too.
TIMINATOR
