350 - 270 Combo Horsepower

gsa612 · 06-22-2015, 11:28 PM

According to the tech. specs the 70/350 and 71/300 402 both run the same intake (flat #287).In order to get the 300/402 to be competitive you need a custom grind camshaft,if you have one of the "off the shelf" cams your leaving 2 tenths on the table,There basically a 325/396 cam with more ex. lift,but don't compliment the semi-open head (105cc) on the 300/402 which produces low torque #'s.With the right combo,cam/converter/gear,carb,light trans,good ring seal,right tune-up ( jetting,timing etc.) it should run with the majority of the cars in K. JMO gsa612

Dwight Southerland · 06-23-2015, 08:01 AM

Here's a picture of a 287 manifold. Doesn't look flat to me. The differences between the '70 and '71 engines are the heads (290 heads flow well and have a good combustion chamber design, 820 heads flow okay but the combustion chamber is sucky; not sure about the other '71 heads), camshaft, and 1.7 points of blueprinted compression (11.3 for the '70 and 9.6 for the '71). See www.classracerinfo.com for the actual calculated compression ratios.

06-22-2015, 11:28 PM	#1
gsa612 Senior Member Join Date: Jan 2008 Location: 100th Meridian Posts: 569 Likes: 116 Liked 280 Times in 139 Posts	Re: 350 - 270 Combo Horsepower According to the tech. specs the 70/350 and 71/300 402 both run the same intake (flat #287).In order to get the 300/402 to be competitive you need a custom grind camshaft,if you have one of the "off the shelf" cams your leaving 2 tenths on the table,There basically a 325/396 cam with more ex. lift,but don't compliment the semi-open head (105cc) on the 300/402 which produces low torque #'s.With the right combo,cam/converter/gear,carb,light trans,good ring seal,right tune-up ( jetting,timing etc.) it should run with the majority of the cars in K. JMO gsa612 Last edited by gsa612; 06-23-2015 at 12:20 AM.

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06-23-2015, 08:01 AM	#2
Dwight Southerland VIP Member Join Date: Dec 2001 Location: Arkansas - In the middle of everything. Posts: 2,002 Likes: 64 Liked 783 Times in 195 Posts	Re: 350 - 270 Combo Horsepower Here's a picture of a 287 manifold. Doesn't look flat to me. The differences between the '70 and '71 engines are the heads (290 heads flow well and have a good combustion chamber design, 820 heads flow okay but the combustion chamber is sucky; not sure about the other '71 heads), camshaft, and 1.7 points of blueprinted compression (11.3 for the '70 and 9.6 for the '71). See www.classracerinfo.com for the actual calculated compression ratios. __________________