Are stock 1988 Formula V6 engine head are THE SAME as the 1987 SE V6.

Same casting, spec, valve, spring, exhaust port (ex: High Output?

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1987 Pontiac Fiero SE

Yes. Also same as used on ALL the '85-'94 V6 Camaro / Firebird 2.8, 3.1 and 3.4, except '89 turbo 3.8. But stay away from the S-10 2.8 heads, those had smaller valves.

[This message has been edited by Isolde (edited 12-03-2010).]

quote Originally posted by Isolde: Yes. Also same as used on ALL the '85-'94 V6 Camaro / Firebird 2.8, 3.1 and 3.4, except '89 turbo 3.8. But stay away from the S-10 2.8 heads, those had smaller valves.

What is the stock valve size on fiero?

quote Originally posted by SebFGT: What is the stock valve size on fiero?

On the 2.8L V6 Fiero engine, the stock valve head diameter is 1.725" on the intake, and 1.425" on the exhaust. The stock valve stem diameter is 0.340" all around.

[This message has been edited by project34 (edited 12-04-2010).]

quote Originally posted by project34: On the 2.8L V6 Fiero engine, the stock valve head diameter is 1.725" on the intake, and 1.425" on the exhaust. The stock valve stem diameter is 0.340" all around.

Intake = 1.720''
Exhaust = 1.425''
Stem = 0.340''

Are ok? Intake a bit more smaller on all 3 intake valve.

quote Originally posted by project34: On the 2.8L V6 Fiero engine, the stock valve head diameter is 1.725" on the intake, and 1.425" on the exhaust. The stock valve stem diameter is 0.340" all around.

quote Originally posted by SebFGT: Intake = 1.720'' Exhaust = 1.425'' Stem = 0.340'' Are ok? Intake a bit more smaller on all 3 intake valve.

The Short Story
The good news is that the intake valve head diameter difference you alluded to is trivial, and likely not worthy of your further consideration.

The Full Story
Here is why I say, "Fuggedaboudit":

I found the 2.8L Fiero valve head diameters listed as 1.725" for the intake and 1.425" for the exhaust on page 36 of this publication: Enthusiasts' Guide to the Pontiac Fiero.

However, I found the valve head diameters for the GM 3.4L crate engine (same heads as the 2.8L Fiero) listed as 1.72" for the intake and 1.42" for the exhaust on page 11 of this publication: GM 2003 Performance Parts Catalog.

So, one might ask with some irritation, which set of numbers is correct?

I contend that both sets of numbers easily could be "correct" because of rounding. Suppose, for example, that the "true" intake valve head diameter is 1.724510000." Rounded to 3 decimals that becomes 1.725," but rounded to 2 decimals that becomes 1.72," does it not?

Perhaps much more importantly, let's consider the magnitude of the difference we're talking about here, (1.725" - 1.72" =) 0.005" --- or only 1/200ths of an inch!


To put that in perspective, take a look at the typical cheapo rulers that one often can find at the "school supplies" section of their nearest supermarket or pharmacy. The smallest gradations those rulers have in my area usually are 1/16th of an inch wide. Now, cut one 1/16ths-inch wide strip from a piece of paper, and then try cutting that 1/16ths-inch wide strip into 12 or 13 equally-sized, narrower strips. IF you can even do that, each one of those 12 or 13 narrower strips will be around 1/200ths of an inch --- or 0.005" in width --- the difference between an intake valve head diameter of 1.725" versus one that is 1.72" wide.

Now, doesn't that make you less concerned about this valve size issue, SebFGT?

... AWESOME REPLY!!!

Exactly the wanted reply. Thanks for all info... Cheers! SebFGT