jtranger

What are the differences between the 461 and 462 heads? Which is a better performing head? Thanks

ragtopman

According to Alan Colvin, and when looking up the 3782461 head, in the notes, he states that 'This head is similar to #3774462 except that the combustion chamber has changed. The external identification symbol has changed.'

Scott Marzahl

I would venture to say that unless you pick up a set of 461X castings, the difference between the two is neglible with everything else being equal.

JohnZ

Both 461 and 462 heads that were factory-equipped with 2.02/1.60 valves had an extra machining cut made to unshroud the intake valve for additional flow that's very obvious when you look for it. Adding 2.02 valves in the field to 461/462 heads originally machined for the 1.94 valves was popular, but if the additional unshrouding cut wasn't made with the conversion as well, the heads wouldn't flow any more air than they did with the original 1.94 valves. Photos below of both heads, with the factory unshrouding cut.

DZAUTO

The first picture in John's reply has the 461 combustion chamber configuration. The second picture is the 462 style.
Notice that area of the 462 chamber near the spark plug hole, that's the main difference between 461 and 462 heads. The 461s are about 60-62cc chambers and the 462s are about 64cc chambers.
I believe the 462 replaced the 461 about 1966.

john neas

Scott aluded to the 461X heads being better. The intake ports were larger. In the 60s these heads were sought out by the sprint car racers due to more intake flow.
Regards

mechron

john no offence intended, but doing work on 461s and 462s in the 70s, the only thing i noticed was the difference in chamber shape (as JOHNZs excellent pics show). the ports were all the same, the only rivision was that cast in area above/below the spark plug hole (depending how you look at it) the 461s in JOHNZs first pic are the hot setup, they provided better quinch--better for power, worse for smog. the 462s were introduced after the the 461s-i think that was the first attemped at smog control (a little less quinch=a cleaner burning engine. but less power.
i look for 461s and lean (grind) the sides of the chamber out to the gasket mating surface to unshoud the valves. then i hit the rest of the chamber to get rid of the rough casting (see JOHN ZS pic one) then i smooth the edges of the chamber with the machined surface of the deck. all these mods allow me to run a10.5-1 compression ratio with regular gas. i also always run with extended tip spark plugs as this puts the spark more into the center of the chamber for a faster burn and more power. i also pocket port (or fully port) any of the 461s i use.

john neas

The published port volumes of the ports are as follows:

Intake Exhaust
461X 176 64
461 161 62
462 161 65

These are unported original heads and without CC ing the heads would probably not be noticed except in minor performance difference. I have three sets of the 461X heads and the only set of heads I worked with from a performance standpoint was used on a car raced at the Monterey Historics in 97. They had a full port, the lightweight LT-1 or LT-4 2.00 !.60 (by memory cant remember if it was 1 or 4). The dyno test (I realize that dyno results can vary) far exceeded what we were aiming for. What part of California are you from? Hope to meet you in the future.
Regards