Engine upgrade

[Tonyrodz]

My budget can go to 3 grand if need be . I just want to make sure I do everything right and research and get a bunch of information from different sources prior to starting this .

I think labor alone will top the $3k mark.

 

[02_Tahoe]

I got a custom exhaust and ordered a CAI that's coming soon for $300,if you get an in person tune I think it's like $350 from black bear, a cam with new valve springs is about $400 but if you're paying someone to put it in it'll be about 1k. So you're at about $1700 with just that. Ported heads for about $600, good set of long tube headers for $500, y pipe for $200. 3k right there and you got a lot more power.

 

[Maximus1]

Hotrod magazine did a story on a 5.3L. They first added a mild cam to a stock 5.3L and gained 65HP dyno proven. Then added headers and it gained 10 more horsepower for a total of 75 hp. Then they swapped out to a more radical cam to a totally stock 5.3L with headers only and the gained horsepower really shocked me. With the cam and headers swap they gained 100 hp dyno proven. Here is a link to the story.

https://www.google.com/amp/www.hotrod.com/articles/ccrp-0410-gen-3-small-block/amp/

I'm currently in the process of changing to the 243 heads, as of now I have the 862 heads. But I have an aftermarket cam that made a huge difference. Headers, TB, custom tune etc, etc etc. I have been really impressed with the horsepower gains from the cam.

 

[Tonyrodz]

Hotrod magazine did a story on a 5.3L. They first added a mild cam to a stock 5.3L and gained 65HP dyno proven. Then added headers and it gained 10 more horsepower for a total of 75 hp. Then they swapped out to a more radical cam to a totally stock 5.3L with headers only and the gained horsepower really shocked me. With the cam and headers swap they gained 100 hp dyno proven. Here is a link to the story.

https://www.google.com/amp/www.hotrod.com/articles/ccrp-0410-gen-3-small-block/amp/

I'm currently in the process of changing to the 243 heads, as of now I have the 862 heads. But I have an aftermarket cam that made a huge difference. Headers, TB, custom tune etc, etc etc. I have been really impressed with the horsepower gains from the cam.

Aren't the 862 heads supposed to be good flowing heads? Had them on my 4.8. On my 6.0 I have the 317 heads, which also are supposed to be good heads.

 

[Maximus1]

No, well I mean the 862 heads have the highest compression ratio with a 58 cc but they have a smaller intake and exhaust valve than the 243. From what I've learned is that the best factory cast heads are the 243 heads and then have them milled .030 to equal the same 58 cc as the 862. And then polish the intake and exhaust ports and you can just about compete with any aftermarket performance head. The next best thing is the 799 head. It's the same as the 243 heads but I learned that the casting is a lot thinner around some of the water jackets and the they are known for cracking. Everything I've read on the 317 heads going on a 5.3 is don't do it. They say it lowers the compression way too low and causes it to be a dog out of the hole. Even with a turbo the engine is a dog with the 317 heads until the full boost kicks in. Hell, by then I plan on being 4 or 5 car lengths ahead of them.

 

[Maximus1]

Sorry was wrong on the cc size.
Casting Number 706 and 862
Head: 1999+ 4.8L / 5.3 Liter Truck
Material: Aluminimum
Part Number:
12559862
12561706
Combustion Chamber Volume: 61.15cc
Compression Ratio: 9.5:1
Intake Port Volume: 200cc
Exhaust Port Volume: 70cc
Intake Valve Diameter: 1.89 inches
Exhaust Valve Diameter: 1.55 inches


Casting Number 243
Head: 2001 LS6 5.7 Liter Passenger Car
Material: Aluminimum
Part Number:
12564243
Combustion Chamber Volume: 64.45cc
Compression Ratio: 10.5:1
Intake Port Volume: 210cc
Exhaust Port Volume: 75cc
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches

Casting Number 317, 035
Head: 2001+ LQ4 and LQ9 6.0 Liter Truck
Material: Aluminimum
Part Number:
12562317 -LQ4
12572317 -LQ9
12572035 -LQ9
Combustion Chamber Volume: 71.06cc
Compression Ratio: 10:1 LQ9 Flat top pistons
Compression Ratio: 9.6:1 LQ4 Dish piston
Intake Port Volume: 210cc
Exhaust Port Volume: 75cc
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches

 

[Maximus1]

You could mill the 317 heads but I think you would have to mill like .100 to equal the 61.15 862 heads and then I'm pretty sure that your intake wouldn't line up correctly. Best is IMHO the 243 milled 0.030 ported and polished.

 

[Maximus1]

Also I've heard that you can take the 243 heads to a machine shop and have bigger valves machined in. If my memory is correct I think you can fit a 2.02 intake valve with a 1.60 exhaust valve. There is a easy way to check. Just get a 243 head and put the two valves (2.02 intake and 1.60 exhaust)in and check the clearance between them. I think you need .008 or .012 clearance.