Piston's for Twisted Wedge Heads???

You can actually run stock pistons with Twisted Wedge heads. Really, it all depends on how much lift you're planning on running, but for a mild cam (TFS Stage 1, FRPP alphabet cam, etc), you're plenty safe on the stockers, or a stock replacement. Several companies do sell pistons with valve reliefs cut for the Twisted Wedge heads, if you'd really prefer to go that route, but it's not absolutely necessary. The TFS heads are the only ones that can get away with no flycutting with a 2.02 inch intake valve because of the canted valves, instead of being an inline setup like AFR, Edelbrock, etc.

TFS actually sells a series of pistons designed to work with their heads, made by Arias for TFS. About $500 a set. Good stuff though. Check Summitt.

Taz92gt said:

So You think that I will be ok with a set of forged pistons with -3cc releifs??

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yes you'd be fine. Ross makes a good piston too, i have a set that has reliefs cut in them for multiple different heads, including TFS heads.

http://www.rosspistons.com/auto_stocking_pistons_detail.php?cat=70&item=47

Going on my fourth season with my motor and the TFS Track Heat Kit. I used Speed Pro forged 10:1 pistons that came in the rebuild kit from Summit. No issues what-so-ever.

Taz92gt said:

So You think that I will be ok with a set of forged pistons with -3cc releifs?? The kit comes with the cam with .499/.510 lift part #TFS-51402000 do you think I will have any problems? Thanks...
Dennis

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You'll be fine. I'm running TFS heads with stock pistons and the same cam.

Im using probe pistons and have over .125 clearance with .550 Lift and 235@ .050 dur. Stock pistons will be fine to just over .500 lift.

the max lift doesnt have much to do with PTV clearance problems. the problem occurs when you have too much duration and when the pistons is heading up to TDC fixing to start the intake stroke.

when this is happening the exhaust valve is open and starts to close as the pistons comes close to TDC, the exhaust valve shuts as the piston comes close to TDC, the intake valve also opens around the same time.

when you have a radical cam, that has alot duration, its possible to have the valves held open too long and the clearance decreases and the chance of the pistons smacking the valve increases.

the trickflow heads are able to clear the big 2.02/1.6 valves on stock pistons on most street cams. the valve are canted, moving the exhaust towards the exhaust side, less likely to hit, canting the valves also unshrouds them for some better airflow.

the valve angles are also changed in the TW heads. stock heads use a 20* valve angle all all the valves. the trickflows use a 15* valve for the intake and 17* for the exhaust.

with these steeper angles the valve opens and heads in more of a perpendicular angle towards the piston, this also increases clearance. the stock heads 20* valves are "layed over" a little more and the edge of valve can be hit easier that a steeper angle where the valve comes more straight towards the piston.

its always good practice to check PTV clearance on any engine, when changing valve size and going to an aftermarket cam. general rule of thumb is .080 for intake and .100 for the exhaust. exhaust needs more b/c the pistons chases the valve shut and the spring has less control over the valve. for all out race engines running alum rods. the clearance should be increased to allow for some rod stretch which happens with alum rods, but you wont have to worry about that.

As per Fox Lake

How big of a camshaft can I really run with my Trick Flow Twisted Wedge heads on my stock shortblock?

It is more of a matter of duration and not lift numbers that matter in this situation. When the valve is open, the piston is on it's way down so lift numbers aren't the problem. The duration is the length of time that the valve stays open and is where you more than likely may get into trouble. In theory, you could run a .700" lift cam and not have piston to valve problems if is has a short duration. Also, you could use a cam with only .400" lift and if the duration holds the valve open too long into the stroke you would have contact. In our experience, we have used the Trick Flow Stage 2 camshaft with numbers at .544"/.563" lift and 224/232 duration @ .050" and have no clearance problems at all on a stock shortblock. Piston to valve clearance should always be checked during assembly, but just try to not to get "hung up" with lift numbers only......there is more to it than that.

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I personally went against the Twisted Wedge head design because I wasn't doing a complete build at the time. However, without a doubt if you're running Trick Flow Specialty Heads you have to get Flat Top pistons. Otherwise you'll always feel like you're missing something.