Hot Rods 327 heads

Ok, i have said to a lot of young guys that i probably forgot more than you know, not being a smart aleck in any way. But true. For instance, did 461 heads have 2.02 intakes from the factory? i always thought that 462 heads had the 2.02 and 461 were 1.94. So set me straight please

 

Both 2.02s and 1.94s... It all depends on what motor they came on.....

 

99% sure the 2.02 461 heads i have are factory . I have had them 45 years or more.

 

You may or may not have known this also........
Can you tell which heads these are without removing them or the rocker covers?




Neither 461 or 462's, these are "291" heads, they are a one year only head usually found with late 1967/early 68 casting dates intended for the 1968 production year.
The giveaway is the hole for a water temperature sending unit on the side of the casting.


And yes, all three castings could have had either a 1.94 or 2.02 diameter intake valve, the engine/hp rating dictated which size.

 

I think the big valves first became available in ‘461’s for the 1964 Corvette 365 and 375 horsepower engines, the ‘63 340 and 360 engines used the 1.94/1.5 valves. The casting dates on your heads will tell the story. Also the ‘462’s had a slightly different chamber and the spark plug location was raised about 1/8” in the chamber.

 

If I remember right, the factory 2.02" heads were also machined to unshroud the valves.

 

Thanks fellow hambers for clearing that up for me.

 

Somehow... This posting was entered twice by the OP?

 

You just can't have enough 327 threads!

 

So true!

 

All 327 heads came with 2.02 valves because we all know that any 327 engine available for sale came out of a Corvette.

 

Yes there was some extra machining around the larger 2.02 valve that the 1.94's didnt get. My grandfather and I have had sets of camel humps that were 1.94 that had 2.02's stuffed in and they run like garbage without that extra machining.

 

While these are 69 Z/28 "186" heads, they are factory 2.02 and you can see the slight machining around the valves to maximize the flow with the larger valve. Only major difference on a 186 head is its the first year of the drilled ends for brackets. Some 186's were angle plug but mostly over the counter stuff.

 

@DDDenny , Neither 461 or 462's, these are "291" heads, they are a one year only head usually found with late 1967/early 68 casting dates inteded for the 1968 production year.
Figures, I'd get one-year only stuff. Are they hard to get parts for?

 

All the same parts.

 

Drag raced a 327 with a set of 492 angle plug heads in a 3040 lb. 5.38 gear O.T. Chevelle, it had a best E.T. of 11.97 but I think it would have been quicker and more consistent with a single plain 4-barrel intake.

 

I have a set of 1964 461s that are 1.94"

 

Those would have come on the 327-300 horsepower engines, the 250 horse 327 used the so-called 1.72/1.50 Power Pack heads.

 

What year chevelle? To me thats really hauling some butt. Engine masters did a dyno comparison to single 4 vs dual and the dual blew it away in both torque and horsepower. Still the look of single or dual tunnel rams always looks sweet. Had the summit dual 450s ram on my 69 4spd nova. Man I miss that car.

 

A 1967 2 door post drag car cut up and has an aluminum floor and trunk, weighed 3040 with me in it.
A single 4 ram is a bitch to keep in tune because the weather affects the set up a lot more.
Had to chase the weather with jetting or it would bog, running the carb with no power valve helped a lot, 327 ran the 11.97 on a cool November day with good air at Great Lakes Dragway, normally ran 12.20s normal summer days and even slower on really hot days, the single 4 ram was terrible for bracket racing.
The 2x4 ram is a whole different animal been running a 434 with a Victor ram with two 660 tunnel ram carbs for a few years with good results.
It's almost like fuel injection

 

434 waiting for its new home in a 56 Chevy gasser, 327 valve covers because they are my favorite sbc covers

 

My 67 chevelle with a 327 with 5.13 gears on a 30" slick 4 speed went 12.99 with 1.94 valves had porting and a big Crower cam and a lot of RPM. That was with a single 4 750 holly It went 13.01 the next week with a Offy tunnel ram and 660's .
Really no difference imo.
The temps or jetting could have likely flipped it either way .
I likely needed the bigger valves and another 500 rpm on the top end to gain much with my set up.
That was 1984 ish at Sears point.

In a Camero I had i switched from stock 1.95 461's to a pair of 2.02 stock unported running a 30/30 cam and I actually went slower. Car was doing 13.40' with 3.73 gears
I Think the 1.94 heads might have been milled more thus more compression. But both heads were 461 castings and unported at the time.
I THINK i had back cut valves and a 3 angle seat on the 1.94 heads .
The 2.02s were factory stock.