5.3 vs. 6.0
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TECH Resident
Joined: Nov 2001
Posts: 851
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From: Houston, Tx
5.3 vs. 6.0 Well I got a few questions. I want to attain 11:1 comp with stock pistons(want it to be a heads and cam car). I know I can do this with the 5.3 heads but from what I understand they don't flow to well. Now the 6.0's flow great but even after milling .030 from what I understand you still only achieve a 10.6:1 CR. So what would have to be done to the 6.0 heads to get at least a 10.8:1 CR? Welding sounds really expensive. <img src="gr_eek2.gif" border="0">
So lets see if yall can answer these:
1. Should I go with the 5.3 or 6.0?
2. If ported could the 5.3's flow around 300?
3. If i get the 6.0's and have 'em milled what all do I have to change?
?Pushrods...what lentgh would I need? What else?
<img src="images/icons/confused.gif" border="0">
4. What are the largest valve that will sit in the stock 5.3 valve seats?(i think the 6.0's are 2.02/1.57)
5. How much does it cost(on average) to mill a pair of heads .030
6. What is the MAX CR that can be run on pump gas(93)
Thanks For the help,
Marty
So lets see if yall can answer these:
1. Should I go with the 5.3 or 6.0?
2. If ported could the 5.3's flow around 300?
3. If i get the 6.0's and have 'em milled what all do I have to change?
?Pushrods...what lentgh would I need? What else?
<img src="images/icons/confused.gif" border="0">
4. What are the largest valve that will sit in the stock 5.3 valve seats?(i think the 6.0's are 2.02/1.57)
5. How much does it cost(on average) to mill a pair of heads .030
6. What is the MAX CR that can be run on pump gas(93)
Thanks For the help,
Marty
I can shift faster than you.
iTrader: (21)
Joined: Nov 2001
Posts: 5,133
Likes: 0
From: Baton Rouge, LA
Re: 5.3 vs. 6.0 A few answers:
1. If you have the money, go with the 6.0l heads. They are a better casting to start with. However, I think the difference between the two heads is going to be less than 10rwhp.
2. My ported GTP stg 2 5.3l heads flowed 301cfm at .550 lift. The 5.3l head has almost identical porting to a standard 5.7l head, so the porting isn't "bad" out of the box. It is just not as good a 6.0;/LS6 head.
3. Yes, you will need shorter pushrods. My guess would be 7.350. However, to be certain, purchase a pushrod length checker. JEGS, Summit, etc. sell them.
4. 2.02/1.57 for both heads. The 6.0l heads come w/ 2.00/1.55 stock.
5. Less than $100...
6. There is no MAX CR you can run on 93 octane. There are alot of factors to discuss when selecting compression ratio. Cam choice, timing, low-temp thermostat,etc. will play a role in this. You want to look at dynamic compression, just not static compression as most people do. This is the biggest factor to look at.
Jason
[ December 16, 2001: Message edited by: Jason99T/A ]</p>
1. If you have the money, go with the 6.0l heads. They are a better casting to start with. However, I think the difference between the two heads is going to be less than 10rwhp.
2. My ported GTP stg 2 5.3l heads flowed 301cfm at .550 lift. The 5.3l head has almost identical porting to a standard 5.7l head, so the porting isn't "bad" out of the box. It is just not as good a 6.0;/LS6 head.
3. Yes, you will need shorter pushrods. My guess would be 7.350. However, to be certain, purchase a pushrod length checker. JEGS, Summit, etc. sell them.
4. 2.02/1.57 for both heads. The 6.0l heads come w/ 2.00/1.55 stock.
5. Less than $100...
6. There is no MAX CR you can run on 93 octane. There are alot of factors to discuss when selecting compression ratio. Cam choice, timing, low-temp thermostat,etc. will play a role in this. You want to look at dynamic compression, just not static compression as most people do. This is the biggest factor to look at.
Jason
[ December 16, 2001: Message edited by: Jason99T/A ]</p>
