My favorite carbs in the world! Spread bore Holleys! I use to modify the Sh1t out of these big ones and used them for racing and on the streets. You got a good benefit of running the small primaries with a large duration/lift camshaft when your vacuum signals to the carb were almost nonexistent, giving you a much better mixture and response to the pedal. And when you're mechanical secondaries opened up, you really felt the difference between the primary and secondary sides of the carb. With a little OEM Holley updated parts like the larger center hung bowls, power valves and acceleror pumps, they'd perform just as well as any brand new Holley out of the box! The better feature is, no need for any sort of adapter plates which are known for leaking gaskets and hight issues with running a regulation stock type intake manifold for best running at mid to higher rpm's was to knotch the divider plates in the center of the intakes and then taking a Qjet adapter flange and hogging them out to be just a Qjet spacer plate. By lifting the carb above and intake about an inch with the modified adapter and the notched divider plate, this would allow your fuel to atomize much better and feed the cylinders which were calling for more air/fuel than in a stock configuration. These were all little power adding secrets that we found out through tons of trials and errors! Now everything today is being put to the test on Dynometers, it's nice to see, that I believe "Power Nation" or one of these channels actually did this testing on the spreadbore intakes and found that in reality that it was definitely a benefit to notch and lift up the carbs. They were using a off the shelf Holley square bore, but it's didn't make it any different how the air performed underneath the Carburetors. Interesting stuff!
One thing you didn't show has how you need to change the vacuum point that affects the power valve . It need to read in the manifold below the throttle plate
The original Rochester Quadrajet, which is the carburetor that this model of spreadbore Holley is meant to replace, worked MUCH better than this particular model.
![Gunna - one of wun [Official Video]](http://i.ytimg.com/vi/w_JtBYqMgk8/mqdefault.jpg)
6:24 you come back with a battle wound on your finger. Good info.
The deth wheel bit me! Thank you
My favorite carbs in the world! Spread bore Holleys! I use to modify the Sh1t out of these big ones and used them for racing and on the streets. You got a good benefit of running the small primaries with a large duration/lift camshaft when your vacuum signals to the carb were almost nonexistent, giving you a much better mixture and response to the pedal. And when you're mechanical secondaries opened up, you really felt the difference between the primary and secondary sides of the carb. With a little OEM Holley updated parts like the larger center hung bowls, power valves and acceleror pumps, they'd perform just as well as any brand new Holley out of the box! The better feature is, no need for any sort of adapter plates which are known for leaking gaskets and hight issues with running a regulation stock type intake manifold for best running at mid to higher rpm's was to knotch the divider plates in the center of the intakes and then taking a Qjet adapter flange and hogging them out to be just a Qjet spacer plate. By lifting the carb above and intake about an inch with the modified adapter and the notched divider plate, this would allow your fuel to atomize much better and feed the cylinders which were calling for more air/fuel than in a stock configuration. These were all little power adding secrets that we found out through tons of trials and errors! Now everything today is being put to the test on Dynometers, it's nice to see, that I believe "Power Nation" or one of these channels actually did this testing on the spreadbore intakes and found that in reality that it was definitely a benefit to notch and lift up the carbs. They were using a off the shelf Holley square bore, but it's didn't make it any different how the air performed underneath the Carburetors. Interesting stuff!
Question why not use drawl through instead of blow through ❓
One thing you didn't show has how you need to change the vacuum point that affects the power valve . It need to read in the manifold below the throttle plate
The original Rochester Quadrajet, which is the carburetor that this model of spreadbore Holley is meant to replace, worked MUCH better than this particular model.
Merica!!! You showed that devil who’s Boss!!!! Jesus. Of the blow through carbs.
Also when doing a carb rub the gaskets with Vaseline and the gaskets wont stick works really slick
Hey thanks for the tip
I wish you could do a demonstration on all carburettors. Side draft’s Dcoe. SU 2 barrels
Maby one day
Have you ran it yet? If you have are there any advantages/disadvantages with the spreadbore?
It's cool that your using a spread bore carb. How did it work?
Its working good thanks man
Was looking for a follow up video. Did it work out for you? Planning on building a blow thru carb myself.
The car is currently on hold im not doing a ls swap on another car i can send you the link from hotrod garage tho
www.hotrod.com/articles/build-blow-carb-less-50/
Was curious why you picked a spread bore
It was 20 bucks lol