LT1-LT4 Modifications 1993-97 Gen II Small Block V8

1.7rr'

Thread Tools
 
Search this Thread
 
Old 02-02-2010, 12:12 PM
  #1  
TECH Resident
Thread Starter
iTrader: (15)
 
speedracer2536's Avatar
 
Join Date: Dec 2007
Posts: 751
Likes: 0
Received 0 Likes on 0 Posts

Default 1.7rr'

i have a cc306 cam. thinking of using 1.7rr. would it change the soundor power of the cam?
Old 02-02-2010, 12:25 PM
  #2  
TECH Addict
iTrader: (1)
 
jaycenk's Avatar
 
Join Date: Jun 2009
Location: Holiday, FL
Posts: 2,210
Received 1 Like on 1 Post

Default

Didn't know you could use 1.7's
Old 02-02-2010, 01:55 PM
  #3  
TECH Fanatic
iTrader: (13)
 
69gto96z's Avatar
 
Join Date: May 2006
Location: Rockwall, TX
Posts: 1,245
Received 15 Likes on 14 Posts

Default

In theory it would change the power, you would be going from a .546/.576 to .580/.612. What springs are you running, can they handle the extra lift? 1.7's in a LT1 is not very common, but I have heard of it being done.
Old 02-02-2010, 03:52 PM
  #4  
TECH Veteran
iTrader: (17)
 
Puck's Avatar
 
Join Date: Oct 2006
Posts: 4,152
Likes: 0
Received 6 Likes on 6 Posts

Default

On a lazy lobe cam like the 306 it will be ok if you have the springs to handle it, but on a more aggressive cam like an XFI specced for 1.6s you will have a hell of a time controlling the valves.
Old 02-02-2010, 04:55 PM
  #5  
TECH Resident
Thread Starter
iTrader: (15)
 
speedracer2536's Avatar
 
Join Date: Dec 2007
Posts: 751
Likes: 0
Received 0 Likes on 0 Posts

Default

im using the 10308-1 spring kit from crane.. its a dual valve spring. will be on spray. they are rated to .600
Old 02-02-2010, 05:48 PM
  #6  
TECH Resident
iTrader: (10)
 
ThreeHonks's Avatar
 
Join Date: Oct 2008
Location: DetroitRacing.com
Posts: 823
Likes: 0
Received 0 Likes on 0 Posts
Default

crane springs have heavy steel retainers and are a weaker springs. I'd be careful
Old 02-02-2010, 07:54 PM
  #7  
TECH Fanatic
iTrader: (13)
 
69gto96z's Avatar
 
Join Date: May 2006
Location: Rockwall, TX
Posts: 1,245
Received 15 Likes on 14 Posts

Default

Originally Posted by speedracer2536
im using the 10308-1 spring kit from crane.. its a dual valve spring. will be on spray. they are rated to .600
I would not chance it.
Old 02-02-2010, 08:33 PM
  #8  
TECH Junkie
iTrader: (31)
 
96lt1m6's Avatar
 
Join Date: Jan 2006
Location: LA$ VEGA$
Posts: 3,782
Likes: 0
Received 2 Likes on 2 Posts

Default

The valvesprings are not really enough for the added lift you are putting with 1.7s..
The biggest problem is going to be retainer to guide clearence..It's not worth adding 1.7s to this cam...I would instal 1.6s and call it a day
Old 02-02-2010, 11:04 PM
  #9  
TECH Veteran
iTrader: (17)
 
Puck's Avatar
 
Join Date: Oct 2006
Posts: 4,152
Likes: 0
Received 6 Likes on 6 Posts

Default

Originally Posted by 96lt1m6
The valvesprings are not really enough for the added lift you are putting with 1.7s..
The biggest problem is going to be retainer to guide clearence..It's not worth adding 1.7s to this cam...I would instal 1.6s and call it a day
+1

I had a LE4 383 grind with barely 500 miles on it that I sold since Llyod told me it would be hell to control with my 1.7 shaftmounts no matter what springs and retainers I run. The extra ratio does not just increase the relative duration and lift, but it makes everything happen quicker. Add that to aggressive lobes and you have a recipe for a very unruly valvetrain that will be a pain in the *** to control at high rpms.

In your case, you would need higher end, more expensive springs and retainers to run them with the 306(which isn't the best choice anyway), and it would not be worth all the extra money.

Install the 1.6s and be done with it .



Quick Reply: 1.7rr'



All times are GMT -5. The time now is 09:15 AM.