Piston to Valve clearance question

JDubz84

New Member
Nov 12, 2004
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My buddy plans on running this set up, but were not sure if we will have piston to valve clearance problems. Stock crank, Ford Motorsports F303 cam, Hyperutectic pistions with dual valve reliefs. He plans on switching to the Trick Flow Twisted wedge heads with 1.92 valves, and getting 1.7 rockers. I have heard that the twisted wedge heads are the only set of heads that you can get 2.02 intake valves and keep your stock bottom end. Is this true? Thanks in advance.
 
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Yes, it's true. If you go to the Twisted Wedge website, it will tell you what the maximum recommended lift is (it's in a .pdf file on the site).

The rule of thumb for 86 flat tops is no more than 224* @ .050" dur, No less than 112* LSA,
You can go up to approximately .550" lift.

I don't know if that will differ on pistons from later year cars. The TW heads don't use the stock valve reliefs.
 
crunchie12268 said:
but the bottom end isn't going to be stock, it is going to have cut pistons in it right?

He already has that setup but has roush heads with 2.02 valves and 1.6's. The pistons are Hyperutectic with dual valve reliefs, so yes, the pistons are already going to be cut.
 
JDubz84 said:
He already has that setup but has roush heads with 2.02 valves and 1.6's. The pistons are Hyperutectic with dual valve reliefs, so yes, the pistons are already going to be cut.


What heads are they cut for?
 
He wants everything to be matched. He kinda just threw everything together on a budget. The heads are not matched for the intake, he wants to sell the Roush heads, and get the twisted wedge. They are cut for the Roush heads.
 
Daggar said:
Yes, it's true. If you go to the Twisted Wedge website, it will tell you what the maximum recommended lift is (it's in a .pdf file on the site).

The rule of thumb for 86 flat tops is no more than 224* @ .050" dur, No less than 112* LSA,
You can go up to approximately .550" lift.

I don't know if that will differ on pistons from later year cars. The TW heads don't use the stock valve reliefs.

so would it be safe to ue TW heads with stage1 cam with a stock 86 short block?
 
JDubz84 said:
My buddy plans on running this set up, but were not sure if we will have piston to valve clearance problems. Stock crank, Ford Motorsports F303 cam, Hyperutectic pistions with dual valve reliefs. He plans on switching to the Trick Flow Twisted wedge heads with 1.92 valves, and getting 1.7 rockers. I have heard that the twisted wedge heads are the only set of heads that you can get 2.02 intake valves and keep your stock bottom end. Is this true? Thanks in advance.
\

Not true!! I have Edlebrock Performer heads with 2.02 valves and stock bottom.
 
JDubz84 said:
As long as the lift is not ovr .550 With a stage one cam, you should have no problems. And the Roush heads use the stock valve locations.

If your buddy has already has already gone through the trouble of having his pistons notched, then why not run AFR 185s?
 
I speak here from experience. I have TW's.

You want 80 thousandths of clearance PV. My car with a stock shortblock did NOT get that much, regardless of cam. My pistons had to be notched.

You must put the heads on, check, then add gasket thickness to the equation. If you don't check, and it's close and you miss a gear, valves will hit.
Same thing goes for the edelbrock 2.02 heads.

Also, TW's as suggested above do NOT go into the stock reliefs, unfortunately i don't have pics, but they hit the piston about 1/2 inch above the stock location.

Alot of time, people do not check clearances because the internet tells them they clear, and they do, just not by enough.
And don't just go by max lift numbers, other cam specs play a factor, such as duration.