Hey guys,
I need to know at approximately what RPM the Thumper heads will stop making usable power. 5,000? 5,500? Higher? Lower?
Reason being, I am getting these heads installed and bought a cam that isn't very suitable for the power range of the heads. I know the ported E7's will make killer low end and midrange power, but the cam I bought likes higher RPM's and will want to scream up to 6k or higher.
It was suggested to me that either the Comp Cams XE264HR or XE270HR would work very well for my setup, because those cams will make great low-end and midrange power which will compliment the Thumper heads nicely.
Here are the specs:
XE264HR: 212/218 dur., 512/512 lift, 114 LSA
XE270HR: 218/224 dur., 512/512 lift, 114 LSA
The XE264HR is described as being a "good H.O. replacement cam" and its power range is rated from 1,500-5,500. The XE270HR is better used with higher-flowing intake and exhaust, and steeper gears (all of which I will have in less than 2 weeks). It's rated power range is 1,800-5,800.
I'm thinking I should go with the XE270HR simply because with my 4.10 gears and the Thumper heads, I'll have plenty of low end already. Plus with the 4.10's, my car rarely sees RPM's as low as 1,500 so it would almost seem like a waste to run the XE264HR since that's when the power starts coming on. Also, when racing, midrange and upper RPM power is very important since you only see low RPM's once and that is when you launch...the rest of the time you are usually above 3,000 RPM.
But, the XE270HR will make power up until 5,800 and I want to make sure that is fine for Thumper heads. If it is the nature of ported E7's to die off around 5,500 or so, maybe it would be in my best interests to go with the XE264HR. Although a guy on 50tech.com ran the Thumper/Tmoss/XE264HR combo in his heavy convertible and complained of too much tire spin!! Hence my reasoning for wanting the XE270HR since it'll soften up the low end a bit.
Thoughts/opinions very much appreciated!!
Thanks guys.
I need to know at approximately what RPM the Thumper heads will stop making usable power. 5,000? 5,500? Higher? Lower?
Reason being, I am getting these heads installed and bought a cam that isn't very suitable for the power range of the heads. I know the ported E7's will make killer low end and midrange power, but the cam I bought likes higher RPM's and will want to scream up to 6k or higher.
It was suggested to me that either the Comp Cams XE264HR or XE270HR would work very well for my setup, because those cams will make great low-end and midrange power which will compliment the Thumper heads nicely.
Here are the specs:
XE264HR: 212/218 dur., 512/512 lift, 114 LSA
XE270HR: 218/224 dur., 512/512 lift, 114 LSA
The XE264HR is described as being a "good H.O. replacement cam" and its power range is rated from 1,500-5,500. The XE270HR is better used with higher-flowing intake and exhaust, and steeper gears (all of which I will have in less than 2 weeks). It's rated power range is 1,800-5,800.
I'm thinking I should go with the XE270HR simply because with my 4.10 gears and the Thumper heads, I'll have plenty of low end already. Plus with the 4.10's, my car rarely sees RPM's as low as 1,500 so it would almost seem like a waste to run the XE264HR since that's when the power starts coming on. Also, when racing, midrange and upper RPM power is very important since you only see low RPM's once and that is when you launch...the rest of the time you are usually above 3,000 RPM.
But, the XE270HR will make power up until 5,800 and I want to make sure that is fine for Thumper heads. If it is the nature of ported E7's to die off around 5,500 or so, maybe it would be in my best interests to go with the XE264HR. Although a guy on 50tech.com ran the Thumper/Tmoss/XE264HR combo in his heavy convertible and complained of too much tire spin!! Hence my reasoning for wanting the XE270HR since it'll soften up the low end a bit.
Thoughts/opinions very much appreciated!!
Thanks guys.