CK5
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Factory stock multi carb setups from GM like the early small block setups in 56/57, 348/409 tri power and the poncho tri power setups ran a choke on one carb and progressive linkage. Usually the center carb on a 3 deuce had the choke. But you are right the full race setups ditched chokes and fully synchronized linkage. I think cross ram setup 302’s were.That's interesting I noticed the little idle screws but not the giant choke blade on one.
Every dual quad I've ever setup has been even linkage with no chokes because for the most part they supply the runners right under them, so if you start making it come in later you may be making those cylinders lean. And a dual quad setup isn't really a winter setup, I usually use the HP style carbs with no choke tower. The receipt showed two of the same carb so they must of removed the choke from one, I'd probably remove it from the other one too. The linkage appears to have the same ratios as all 4 arms appear to be the same length, plus if they have different ratios you would need a slider or something to let the linkage start to move without moving the 2nd carb as they would have different travel amounts.
But I totally get the idea to keep it stock. It’s still rowdy if that video is any indication!
Progressive linkage makes more sense on a factory triple deuce setup than a dual quad. If you are using only the center one it's not much different than a single two barrel when only the center carb is open. Though I did not know that, I have never used any two barrels, not even three at the same time. 
Dual quads make more sense, it's a V8 not a V6.
It'll be interesting to see which one he chooses.., its not permament so he can always switch it if he likes.
I agree with you, the dual quad does look sweet, and those headers he is using go with it quite well. I would get a modern ignition for it, preferably a CDI box.
I have a question, in SBC in mid year 1971 they hardened the valve seats to run reliably with unleaded gas. I think they hardened the cast iron around the exhaust seat via induction, not a separate press in seat. How is that with the 455 olds? I would check into that if you don't know the answer. Or you could run the additive.
Dual quads make more sense, it's a V8 not a V6.
It'll be interesting to see which one he chooses.., its not permament so he can always switch it if he likes.
I agree with you, the dual quad does look sweet, and those headers he is using go with it quite well. I would get a modern ignition for it, preferably a CDI box.
I have a question, in SBC in mid year 1971 they hardened the valve seats to run reliably with unleaded gas. I think they hardened the cast iron around the exhaust seat via induction, not a separate press in seat. How is that with the 455 olds? I would check into that if you don't know the answer. Or you could run the additive.
IME…
I have run my double hump heads without hardened seats for a couple decades now, and ran them uncountable times to 6700.
Everytime I check the valve lash, there seems to be immeasurable difference in lash, indicating to me the valves are happy in their oem cast iron seats. Which makes me question if hardened seats are really needed? My head guy never thought so for my application.
I have run my double hump heads without hardened seats for a couple decades now, and ran them uncountable times to 6700.
Everytime I check the valve lash, there seems to be immeasurable difference in lash, indicating to me the valves are happy in their oem cast iron seats. Which makes me question if hardened seats are really needed? My head guy never thought so for my application.
I've personally seen them fail in an old 302 SBC in a 69 Camaro. The seat failed and it kept beating the valve deeper into the head which then the rocker can hold the valve open since the seat is further away, and makes it worse very fast and it can burn the valve.
I think its a matter of how much they are used, they can last for so many miles before they fail, perhaps if its not driven very often because it's a toy it could last many years, I wouldn't trust it myself.
But its possibly he has factory hardened seat area in 1971, not sure on the 455 head.
I think its a matter of how much they are used, they can last for so many miles before they fail, perhaps if its not driven very often because it's a toy it could last many years, I wouldn't trust it myself.
But its possibly he has factory hardened seat area in 1971, not sure on the 455 head.
My 67 firebird heads are toast because of unleaded.
The valves are 1/4" deep in the head
Well holy crap, what an amazing thread!!!
A guy once told me that after exhaust seats (non-hardened) have been used for many years and many miles with leaded fuel, then the need for leaded fuel goes away in many cases. Something about the lead being embedded in the valve seat. I have no idea if there's any truth to that.
A guy once told me that after exhaust seats (non-hardened) have been used for many years and many miles with leaded fuel, then the need for leaded fuel goes away in many cases. Something about the lead being embedded in the valve seat. I have no idea if there's any truth to that.
My valve seats were reground when the headwork was completed….not sure how deep the lead could get into the metal, but my understanding was that the lead was to “cushion the valve as it slammed against the seat.
I would assume that heavier valve springs and a higher lift cam would worsen the problem. I also thought this was only a problem with aluminum heads, but my experience there was on old volkswagens, not American iron.
Yeah most old European engines have been aluminum so they had the hardened seats but American engines have been mostly cast iron which was good enough with lead in the mix.
Obviously not every casting was the same and some are harder than others.
All I know is some seem to survive unleaded and some don't.
I still have some of the "insteadolead" additives I bought thinking I had a running engine but when I checked compression it was obvious my valves were not holding pressure and I never got to run this engine
By the way chevrolet tried in the 70s to build an aluminum block but didn't want to put a steel liner to save $8 per engine it was a 4 cylinder that went into the Vega.
Funny thing is they used a cast iron head.
It was the worst failure ever and then the following year they replaced it with a cast iron block nicknamed the iron Duke
Funny thing is they used a cast iron head.
It was the worst failure ever and then the following year they replaced it with a cast iron block nicknamed the iron Duke
