Welder7018

Ok I'm debating on getting gt40 heads for my 89. I want to know what are the benefits of the heads. And what are the cons of it.

ColemaNation747

They only fit a V8, so unless you're signature thingy down there is just old....

Welder7018

I bought a 89 5.0 Saturday

mr7confused

I've heard they work best as a package deal, with intake manifold(s) of larger volume allowance and exhaust ported to match. I am curious, though.

97f150ny

I personally know tthe GT40P heads make a difference. The biggest difference between the GT40 and the P heads are the combustion chamber and plug location. The P heads have a smaller C.C. than the regulars which bumps comression some but you either need the stock manifolds or special headers to clear the plugs. I know BBK unequal length with 90 degree plugs will clear them. Either head will be an improvement over the stock E7 or E6 you have now. Also you could use them with 1.7 rockers while ur at it.

LOCO LAPTOP

Cons? no cons.

They definitely help on power with headers and a full exhaust, GT40P are better heads but you need to spend more on headers.

Here a video on a stock bottom end 302 .040 over, with GT40, LT headers and full dual exhaust on a 3.55 rear.

mr7confused

Mother of god. Wish mine did that.
Due to smog restraints however, I cannot.
When an engine is bored .040 over, does that mean it was pulled and the pistons were removed to shave the cylinders out .040, then new slightly larger pistons were put in?

LOCO LAPTOP

Pretty much.

In my case engine was pulled, Clean and bored out .040 put new .040 pistons & rings, with polished crank with new main and rod bearings. (FYI .040 doesn't make that much of a difference.)

Now for smog I live in FL so its not needed. (thank god) but I think explorers GT40P heads have smog holes if you need smog.

Welder7018

Ok good deal I will be looking for one. Would a mustang intake and upgraded throttle body make it more peppier?

LOCO LAPTOP

I wouldn't recommend it, You would lose the low end torque.