INTERNAL ENGINE MODIFICATIONS Valvetrain |Heads | Strokers | Design | Assembly

Head / Cam advise

Old Jun 14, 2013 | 03:07 PM
  #11  
Jake99's Avatar
TECH Fanatic
iTrader: (5)
 
Joined: Dec 2009
Posts: 1,241
Likes: 0
Default

The higher compression will help with the part throddle power at lower rpm (od) were it's going to be hard to get any aftermarket cam to help much. I use to pull with my 5.3 when it had a cam, pretty lazy in od but when it down shifted to third it pulled like a freight train.
Reply
Old Jun 15, 2013 | 12:44 AM
  #12  
ls6musclehead's Avatar
Thread Starter
On The Tree
iTrader: (1)
 
Joined: Nov 2006
Posts: 103
Likes: 0
From: Richmond, KY
Default

See that's just it, most of my cruising and towing is going to be 65mph or under. It does
pretty good in the cruising dept. But from a dig it sucks and the convertor I got was for
heavy towing in a 4L65e and the builder said he wouldn't warranty it if I wanted anything over 2000 stall. I am looking for durability but also figure I shouldbe able tweek things a little over the stock cam without totally killing what fuel mileage I have.
I kind of think that I have too much compression right know anyway. The bottom end is lq4 dished pistons and the heads are 97(?) Ls1 heads. I think they are the 66cc heads w/ 2.00 intakes. Everything I read said the 317s I pulled off flowed better but I thought that the upped CR w/ the smaller combustion chamber and the 1.8 rockers would make it run strong. I was wrong. I have watched several logs very carefully for knock retard with this set up and none is present so the only thing left to do is put better heads on it and while I am in there swap to a better cam.
Another thing Richard mentioned was that the 862 heads I talked about in my first post, is the CR would be like 11 or 11.5:1 and I would have a hell of a time keeping the torque down low due to low rpm cams not bleeding off enough pressure and knock would kill timing and I would be fighting a viscious circle of headaches. He also mentioned the only way he would run that much CR would be to go e85. I am not that big of an ethanol fan to do it on a daily driver.
Reply
Old Jun 26, 2013 | 11:59 PM
  #13  
ls6musclehead's Avatar
Thread Starter
On The Tree
iTrader: (1)
 
Joined: Nov 2006
Posts: 103
Likes: 0
From: Richmond, KY
Default

So I got my heads back from the machine shop and while they were there I had them cc'd and the combustion chambers are right at 63cc, intake runners are 212 cc? I think thats good. It would probably be better on a larger displacement engine but definately better than whats on my engine now. The machine shop manager also does port work at home and has a flow bench so I thought he may know a few things about how they look.
He said that they had the critical points that he trys to incorperate in his port work and that the cnc program used did not look like a hack job, So I am optimistic.
Now based on the new knowledge of what the macinist relayed to me, would these heads be too much for a small cam and low speed torque that I am looking to achieve?
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
JFortner5
GM Engine & Exhaust Performance
7
Aug 12, 2015 08:46 PM
BIGD4504
GM Engine & Exhaust Performance
10
Jul 28, 2015 11:46 AM
steves86ta
GM Engine & Exhaust Performance
5
Jul 28, 2015 10:21 AM
sauldgold
GM Engine & Exhaust Performance
3
Jul 23, 2015 02:15 PM
Aboss
GM Engine & Exhaust Performance
7
Jul 9, 2015 10:28 AM


Thread Tools
Search this Thread

All times are GMT -5. The time now is 07:00 AM.