So I was at a car show with my 86 GT. A feller came with his 87 GT (both are fastbacks). We were looking at the engine where it is cast Fiero. He said that the 86 should have the decal and not the cast Fiero. He thinks maybe my engine was replaced with an 87 at some point (I don't really know the history of my car very well). I thought I once read that in late 86 V6's they started to use the cast and got rid of the decal. Does anyone know anything about this? Thanks for your time.

quote Originally posted by Rhodesia1977: I once read that in late 86 V6's they started to use the cast and got rid of the decal. Does anyone know anything about this? Thanks for your time.

Never heard that before, but can you check your VIN number and see if it's very near the end of '86 production? I think the most likely explanation is that someone swapped the '87-88 style upper plenum onto your engine. An easy conversion.

I have an 86SE that was produced in late May of 86. The original engine had the FIERO decal instead of the engraved FIERO.

That makes the most sense. I also found a Carfax report from 2017 that it had a slave clutch install and manual transmission work BUT it is an automatic. Maybe the original entire engine was removed. Is there any type of marking on the engine itself that would tell the date of the engine? Thanks for the reply.

Original engines were supposed to have a serial number on the starter flange bellhousing mount area above the starter. I didn't read all of this link but there is a photo by rubyredfiero that shows part of the vin number just below the thermostat housing. https://www.fiero.nl/forum/...410-1-048013.html#p6

There were slight changes in the V6 engines through all years. Most of them were internal. I have read that in 87, the oil galleys throughout the block were enlarged for better oiling. So, that would be an improvement over the earlier engines. Of course, the 88 got the internally balanced crank.

Hey, thanks for the info. I think I have it down to either, the engine in now is not the original (possibly an 87) or they put on a later plenum with the Fiero cast onto my original 86 V6. Thanks a lot for your guidance.

It's a fact.......that 85 & 86's have the "Fiero" sticker and the 87-88's have the engraved plenum.
Because it is common that many in the V6 Fiero community take off their plenum & valve covers
(because they need repainting & refinishing) they use that opportunity to swap out their plenums
with someone with another set, from a 87-88 V6 Fiero in a yard, etc.
Kit

I swapped in a late model-engraved intake- I like it more. I also took the opportunity to "port" the intake at the pinch-point...After painting it, I installed it and it looks great...but it makes the rest of the engine look bad (need to clean/detail/paint the rest of the engine)

[This message has been edited by cvxjet (edited 07-26-2022).]

So the pic of that 85 V6 on the left is a decal? I have never ever seen one. Is it just the Fiero part or is the part with the lines too? Also, how long did the original decals last? I would guess they would wear off easily with all the heat. Very interesting. Thanks for your help!

Here is a pic of the old (1985) intake with decal...this was in 2017....so it was 32 years old then;

Nice! Thanks for the pic.

quote Originally posted by cvxjet: I swapped in a late model-engraved intake- I like it more. I also took the opportunity to "port" the intake at the pinch-point...After painting it, I installed it and it looks great...but it makes the rest of the engine look bad (need to clean/detail/paint the rest of the engine)

I dig that newer intake looks! Well done

That pretty much answers both my questions. Thank you. I found out after more engine research that my 86 GT just had the 87 manifold but the engine is 86. Is it true that the 86 V6 had a few more horses than the other years? I read that in a Fiero history book. Not sure how true it is though.

The sticker on my 86 came off so I made my own.

It looks awesome!

The first year (1985) V6 was rated at 140 HP...Later, they "Modified" that rating to a slightly lower 135 HP...there really is not any difference between the two engines (Power-wise).

Correct. I was just looking at a table from the Pontiac Fiero Performance Portfolio (a neat book from the Fiero Store, you probably have it!) And it does say that the V6's for 85 and 86 we're at 140 horses at 5200 rpm. Apparently 87-88 V6's dropped to 135 horses. I'm not sure if one could really notice the difference like you said. But hey, thanks for the information. Hopefully next year, I will be getting a Mera but I have to ask the wife.

From what I was told the HP really did not change it was just the adjustment GM made in how the calculated it.

I am upgrading to the engraved intake now..

[This message has been edited by hyperv6 (edited 08-08-2022).]