Ok to run trick flow twisted heads with stock pistons?

oldfox · Aug 16, 2011

Hi, I am looking at a set of used Trick flow twisted heads.
Will there be a piston / Valve clearance problem if I run stock flat tops w/ valve reliefs? The heads have 202 and 160 valves 60cc combustion chambers.
the cam will be a ford F303 512 lift. And I will be using MLS head gaskets.
Engine will be a 5.0
Should I be concerned about clearance problems?
Thanks

LarsD · Aug 16, 2011

It would be a good idea to clay the heads if it is an 87-93 block, if it is an 86 or older, I don't think you can run a cam that big. What year is the block?

BlownFiveLiter · Aug 16, 2011

You should be fine. The canted valves allow for a pretty good lift and large valves. The TFS1 cam has .499/.510 I/E lifts and they sell it in the kit to use on a stock engine. The F303 is only .002 more on the exhaust and the intake valve opens when the piston is traveling downward anyway.

JungleJoe · Aug 16, 2011

I sure hope so...The cam I am using is WAYYYYYY bigger than that!

Rick 91GT · Aug 17, 2011

No problem at all, the rotated valve location gives you a lot of clearance over a online valve head.

NIKwoaC · Aug 17, 2011

Realize that lift has absolutely nothing to do with PtV clearance. Peak lift occurs when the piston is deep in the bore, so for all practical purposes, you could have a 1.000" lift cam and not run into trouble. It's all about where the valves are when the piston is at TDC, which is the overlap stage. Cams with wide durations and lots of overlap will have less PtV clearance than mild cams with minimal overlap.

A perfect example of this is my engine. It's the stock '86 bottom end with stock, untouched true flat top pistons. My car currently has 1.6 roller rockers which puts lift around ~.570" on both the intake and exhaust. However, this cam has VERY mild duration numbers and minimal overlap. NO valve clearance issues whatsoever.

Whatever the scenario, though, YOU HAVE TO CHECK. Checking PtV is really easy, there is no reason not to do it.

Gregg@TFS · Aug 17, 2011

NikwoaC said:
Realize that lift has absolutely nothing to do with PtV clearance. Peak lift occurs when the piston is deep in the bore, so for all practical purposes, you could have a 1.000" lift cam and not run into trouble. It's all about where the valves are when the piston is at TDC, which is the overlap stage. Cams with wide durations and lots of overlap will have less PtV clearance than mild cams with minimal overlap.

A perfect example of this is my engine. It's the stock '86 bottom end with stock, untouched true flat top pistons. My car currently has 1.6 roller rockers which puts lift around ~.570" on both the intake and exhaust. However, this cam has VERY mild duration numbers and minimal overlap. NO valve clearance issues whatsoever.

Whatever the scenario, though, YOU HAVE TO CHECK. Checking PtV is really easy, there is no reason not to do it.

Great example. The F cam in a (85-95) stock bottom end, 1.6 rocker, unmilled Trick Flow Twisted Wedge head will clear without issues but like stated above whatever the scenario is it is best to verify PTV.

NIKwoaC · Aug 17, 2011

Gregg@TFS said:
Great example. The F cam in a (85-95) stock bottom end, 1.6 rocker, unmilled Trick Flow Twisted Wedge head will clear without issues but like stated above whatever the scenario is it is best to verify PTV.

By the way, Gregg, I love my TWs.

Rick 91GT · Aug 17, 2011

Kissing Ass...lol

In all seriousness the IFS is one if the most efficient heads on a stock style shortblock.

With the MLS gasket you need a extremely smooth finish no factory block will be good enough unless you deckto it. Why do you feel the need to use them?

NIKwoaC · Aug 17, 2011

Rick 91GT said:
Kissing Ass...lol

Just giving credit where credit is due. Heh.

Ok to run trick flow twisted heads with stock pistons?

oldfox

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LarsD

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Rick 91GT

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Ok to run trick flow twisted heads with stock pistons?

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