Same engine a year and a half later. Changes were swapped carbs for Hilborns, Chevy hi po cam for Isky 550 C roller cam (550 lift), and stock pistons notched for valve clearance. This engine set and held NHRA B/SR record for 2 years, until we built a full on race engine which held the record for 3 more years. Given the ports and valves we had to work with in the mid 60's, 550 lift was about all it needed.
Here they are...and, yea, I can’t believe someone went to all the work on a set of heads that didn’t flow for crap originally...and may still not. Apparently they were built as part of some Hot Rod magazine engine build competition something or another.
Carbking....I lived in the same era. 245 hp and 270 Corvettes were very docile and all the guys I knew loved them. They idled perfect using the stock progressive linkage. They idled on both and ran on the rear until wanted it all. I modeled my dual quads using Carter WCFB’s on the Corvette style and haven’t touched them in 5 years only checking them with a UniSyn twice on a 296” engine. Both carbs came off a single carb engine. No jet/metering rod changes. I’m running an automatic trans with a stock converter, stock cam and 2.74 rear gears in a 3500 pound car. Most guys bitched about buying the air cleaners since they were sealed and in 60-61 went to the 3 piece air cleaner. An older guy my dad new, 45, drove his 58 245 15000 miles a year. If I was doing a SBC with dual quads I’d get 2 stock Carter’s and put them on with the stock dual quad linkage in a heartbeat all you to do is drill a lower hole one the front carb stock linkage if it’s not there. I’d open the front choke and idle on both. Mine have never ever loaded up and I jump on it every once and a while. Maybe I’m lucky .... maybe not.
My nickel's worth......... Snotty/lopey idle comes from a tight LSA ( 108-106*) You can advance the cam to sorta clean-up a snotty cam to make it work better on the street. Duration @050 also contribute to the lumpy idle. Too much of duration and the engine won't run worth-a-$hit under 3500RPM! To get that boom-boom thump at idle go bigger on the exhaust duration than the intake. It let's the exhaust valve "hang open" a little longer and some of the combustion is heard out of the headers. Lift don't do squat for the sound you're looking for. Too much and it will reek havoc on your valve train and just constantly get in your purse/pocket$. To get the sound (and power) UR wanting.................you gonna need to lose the P'glide and step up to a 4 speed with a decent rear gear 3.73:1 3.91:1 4.11:1. You just THOUGHT you were gonna get by cheap!! This 'hot-rod' business is like a snowball on a hill! 6sally6
Jimmysix - enthusiasts have different levels of tolerances on driveability. I personally was quite happy with an OT daily driver that my friends couldn't even get off the line; so I do understand this; however: Carter totally redesigned the idle circuit on the dual quads from 1956 to 1957, recalibrated the redesigned idle circuits again in 1958, and changed the design (again) of the rear (primary) carburetor in 1959, ALL to attempt to improve idle characteristics. So while you, and some other enthusiasts were happy, obviously Chevrolet and Carter were not. Jon.
WOW. I haven't had the time lately to follow up. It appears you all having a fine conversation among yourselves. Lol. I appreciate all the advice, even the smart ass ones. The end result of my story/decision is... The correct manifold and cam i wanted was and still on backorder. So maybe thats a sign. Fuck it, i srnt all the shit back to Jegs. Got all my money back. What an education.
The H.A.M.B. is like a swelled up Carcass on the side of the road— be careful when you poke it with a stick!!!! Sent from my iPad using The H.A.M.B. mobile app
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