[BahmerL]

Can anyone tell me what were the HP ratings for the 327 offered in the 64 Impala SS? Or if it makes a difference this one has a Powerglide Tranny.

[johnnya]

The '64 327 was available in 250HP & 300Hp in passenger cars. I would suspect it's a 250HP with a Powerglide.
The heads were different, and the carbs were different.
The 300HP had double hump heads and a Carter AFB carb, while the 250HP had 283 Power Pack heads and a Rochester 4 barrel.
JA

[Bort]

To my knowledge, I have a 327 from a '67 Impala and I'm currently restoring a '64 Impala, it depends what's on it. From the factory in '64 they did have 2 different setups (carb, heads, and manifold differences) on the 327's.
Double hump heads with 650 carb. and headers was 364HP.
The lower performance heads with 600 carb. w/out headers pushed 324HP.

[RippinRon]

I had a 65 327 250hp a few years back. It had 461 heads and a rochester 4-jet carb. I believe it was from a truck if memory serves me correctly. It was early 65 the intake and heads were date Jan 1965.

[johnnya]

RippinRon said: "I had a 65 327 250hp a few years back. It had 461 heads and a rochester 4-jet carb."
Starting in '65 all 327's had double hump heads, but 62-64 250HP 327's had the old Power Pack heads.
JA

[steve t]

Originally Posted by johnnya

RippinRon said: "I had a 65 327 250hp a few years back. It had 461 heads and a rochester 4-jet carb."
Starting in '65 all 327's had double hump heads, but 62-64 250HP 327's had the old Power Pack heads.
JA

i thought double hump heads were power pack heads

[Guy Hiltz]

re: 1964 Impala SS 327

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To my knowledge, I have a 327 from a '67 Impala and I'm currently restoring a '64 Impala, it depends what's on it. From the factory in '64 they did have 2 different setups (carb, heads, and manifold differences) on the 327's.
Double hump heads with 650 carb. and headers was 364HP.
The lower performance heads with 600 carb. w/out headers pushed 324HP.


Your figures are way off,only the 'Vette fuelie 327 had over 360 HP,and that was with the Duntov 30-30 solid cam,not available in the Impala.None had headers,I beleive all had the rams horn exhaust.There was no 327 rated at 324 HP.As stated above,250 & 300 HP versions were available,later years had the 327's rated at 300,350 & 375 HP.

[lanierledford]

Power pack heads had a triangle on top of a sq. on the end of the heads near where the head meet the block
double hump heads had a half circle starting at one side of the sq. with a flat space then another half circle to the other side of the sq.
Fuel injected heads had two triangles on top of the sq.
I've only seen one set of fuely, years ago ( I think they were 365 hp)
The double humps came in 250.275, and 300 hp
I've had a 65 chevelle 327-300hp 4 speed
and a 66 chevy II 327-275 hp 3 speed col
both ran like a stripped * monkey

[Hippie]

I've owned several '62-'64 Impalas over the years. 'johnnya' has it right, plus the 300HP got the 2-1/2" Ram's Horn exhaust manifolds and a every one I ever saw had a dash mounted tach. I think they were available with a PG or 3 on the tree also but most people that bought a 300HP went for the 4 gear.

[johnnya]

Here's my feeble attempt at artwork showing the differences in the head markings.
Maybe an interesting story: In '65 my uncle bought a new Impala with a 250HP 327. As I admired the new car and it's engine, I noticed 1 double hump head (we just called them 300HP heads, then) and 1 Power Pack head.
My uncle took the car back to the dealer and they poo poo'd his claim, saying the casting marks were just hot rodder's imagination, and didn't mean anything.
He said "pull a 300HP head and a power pack head from stock and see what they look like."
They had to eat their words and immediatly set about replacing the PP head with a 300HP head under warranty.