My buddy just recently changed the sparkplugs on his 91 T/A. It's a 305 TPI, just like my 89 Formula. All of his plugs go into the side of the block... makes sense right? Well...

On my 89 305 TPI there are three plugs on either side of the block, and then two in the rear. Yes, the rear, On either side, in the back of the heads, before the firewall.

This was the first thirdgen I've ever worked on, so I assumed it was something common to 305 TPI heads... aparently it's not the same across the board.

So what the heck is up with that?

 

Hey?

 

Small blocks have 2 different ways plugs go in....angle and straight.

Thats it. None go in from the back. (if I read your post right)

They all come in from the side of the cylinder head.



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ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R

GO #3

 

Are you serious? I mean, there are really plugs that screw into the rear of the heads? Do they have plug wires going to them too... and do they go to the top of the HEI (not glued to the side of the cap)? I mean, you do know how to tell the difference between a V8 and a V6 right? They are stock heads? I just seriously hope we all are misunderstanding what you mean by "in the back of the heads"...

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock... all the suspension stuff... 9-bolt posi disk is in... K&N filter... 93 octane...

-=ICON Motorsports=-

 

ok with all this talk, I'm seriously doubting my sanity. Perhaps I was halucinating? No I don't think that's it. As I remember, there were the three a side which I got to from under the car, and then the two on the back, around the corner. I don't know how else to describe it.

I'll look on lunchbreak and get a better description, not that I can SEE them. I wouldn't have posted this if I thought it was normal. I mean, I'm really curious here. I assumed they were stock heads.

Yes it's a v8 It's a 305 TPI. It moves... surprisingly well, I've done just a few free mods, and cheap ones such as exhaust, porting on intake, and a few other things. It's a strong car. No slouch at all.



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"I put my 42 sticker on the
back so other cars can see
it...."

 

Do you mean that you can get 3 plugs from up top with the hood open and the last one from only from underneath the car... but there are 4/ side, right? ****, with my headers, it is way easier to get all 4 from underneath the car, but they all stick out to the side of the block. Mine are straight (90 degrees to the heads), but some heads can come with an angled plug (about 60 degrees from the heads). That is to clear some headers.

Try changing the plugs on a LT-1...

 

if you have a v8 you have 8 plugs, 4 per head. maybe you got mixed up looking down from the top and then looking up from under the car. could ou of counted the same plug twice?

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-=ICON MOTORSPORTS=-

 

89,

The two rearmost plugs could be construed as being "on the back" since they are located behind the Y-pipe flanges of the exhaust manifolds. The Y-pipe connections are, however, located between the last two cylinders on each head, and do not define the back edge of the head as you may have presumed.

Because of this, three plugs are forward of the exhaust pipe and one is behind the pipe on each head. The plugs all still thread into the side of the cylinder head (not the block) and are roughly at the center of each combustion chamber. As some have stated, some SBC heads have the plugs screwed in at an angle, but the tip location in the chamber ends up being in nearly the same position, but facing the valve opening a bit more.

As long as you got eight new plugs installed and connected somewhere in the engine (preferably where the old ones came out), you should be set for the next several thousand miles.

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Later,
Vader
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"Make Me Bad"
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