HP Reduction Request

oldskool · 03-06-2017, 05:57 PM

This sounds like a great idea to me.

I've wondered why a lot of 2-barrel BOP engines are not raced. When I look up the specs, it appears that some of these 2-barrel engines are only rated maybe 40hp less than a very similar engine which can use an 800cfm Q-jet.

So, that brings up a question which should be in line with this thread. For most GM carb engines, 350 cubes & bigger, aprox how much less power is possible when only a 2-barrel is allowed ?

It appears to me that a 2-barrel would be the limiting factor, whereas an 800 Q-jet would not pose a limit at all, since there are lots of 9 & 10 sec cars, using 750 & 800 Q-jets.

So, considering this, what would be a good number to begin with, for most GM BOP 2-bl engines, that are not being raced ? Or, to put it another way, how much less should the initial factor be, as compared to a very similar 4-barrel engine ?

Since I'm a Pontiac guy, I'll just use a '76 Pontiac 350 as an example. I just looked it up on the Class Racer Info site. The 2-barrel version is factored at 220hp. The 4-barrel version is factored at 260hp. I've seen the 4-bl version in a competitive car. Have never seen the 2-bl version. So, aprox how low would the factor have to be, to make the 2-bl version competitive, or at least run a safe amount under the index ? I'm assuming a properly built & tuned car.

http://www.classracerinfo.com/Engine...3&MAKE=Pontiac

http://www.classracerinfo.com/Engine...4&MAKE=Pontiac

If this post is out of order for this thread, please delete it.

Thanks !

03-06-2017, 05:57 PM	#8
oldskool VIP Member Join Date: Dec 2014 Location: The Land of Bayous, Boudin & Crawfish Posts: 1,668 Likes: 223 Liked 747 Times in 362 Posts	Re: HP Reduction Request This sounds like a great idea to me. I've wondered why a lot of 2-barrel BOP engines are not raced. When I look up the specs, it appears that some of these 2-barrel engines are only rated maybe 40hp less than a very similar engine which can use an 800cfm Q-jet. So, that brings up a question which should be in line with this thread. For most GM carb engines, 350 cubes & bigger, aprox how much less power is possible when only a 2-barrel is allowed ? It appears to me that a 2-barrel would be the limiting factor, whereas an 800 Q-jet would not pose a limit at all, since there are lots of 9 & 10 sec cars, using 750 & 800 Q-jets. So, considering this, what would be a good number to begin with, for most GM BOP 2-bl engines, that are not being raced ? Or, to put it another way, how much less should the initial factor be, as compared to a very similar 4-barrel engine ? Since I'm a Pontiac guy, I'll just use a '76 Pontiac 350 as an example. I just looked it up on the Class Racer Info site. The 2-barrel version is factored at 220hp. The 4-barrel version is factored at 260hp. I've seen the 4-bl version in a competitive car. Have never seen the 2-bl version. So, aprox how low would the factor have to be, to make the 2-bl version competitive, or at least run a safe amount under the index ? I'm assuming a properly built & tuned car. http://www.classracerinfo.com/Engine...3&MAKE=Pontiac http://www.classracerinfo.com/Engine...4&MAKE=Pontiac If this post is out of order for this thread, please delete it. Thanks ! Last edited by oldskool; 03-06-2017 at 06:02 PM.