Got my heads back from machine shop

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Dec 7, 2012
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Sent off a set of 706 heads to the machine shop for surfacing, valve grinding, cleanup and assembly. Super happy with the final product. They look like new.

These will be going back on a SBE Gen 3 5.3 with 250k miles on the clock. Original valves cleaned up with a double valve spring kit good for .600 lift. Sloppy Stage 2 cam 228/230. LS7 lifters, new lifter trays, trunnion upgraded rockers, FelPro MLS head gaskets, billet timing sprockets, New Melling oil pump.

Going with a truck intake, return style fuel rails with 80lb Deka injectors. Running a FiTech Ultimate LS ecm with trans control. Hoping for a solid 350hp and planning for turbo in about a year.
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If you dont mind me asking, how much did they charge for that?
About $500. Man they were dirty. I also had the bright idea to degrease them myself and in the process left one head outside figuring rain wouldn’t matter. Lol I was wrong. Rusted the valve seats. So I had the machine shop do all. I laid out all valves and was just gonna have the machine shop surface them and I was going to lap valves myself. But all in all the final product is even better.
 
That's a whole lot of injector for such a small, low power build. A 42# would be a much better choice. I realize you plan on going turbo eventually and you're probably trying to save having to buy two sets of injectors.

Even so, 80# will likely have your fighting a really short pulse width at idle, making it difficult to manage a reasonable afr at idle in a small cam 5.3L at idle and end up running rich.
 
That's a whole lot of injector for such a small, low power build. A 42# would be a much better choice. I realize you plan on going turbo eventually and you're probably trying to save having to buy two sets of injectors.

Even so, 80# will likely have your fighting a really short pulse width at idle, making it difficult to manage a reasonable afr at idle in a small cam 5.3L at idle and end up running rich.
Hmm gotcha. So if you had a set of 80# even at idle on a turbo build you’d have a wonky afr? Another set is what it is. thanks for the info!
 
Hmm gotcha. So if you had a set of 80# even at idle on a turbo build you’d have a wonky afr? Another set is what it is. thanks for the info!
You'll want some sort of boost referenced fuel system that lowers pressure at idle, otherwise you'll probably have an idle surge and/or P0172 rich code.

I assume if you install one without a turbo it will just run lower pressure all the time which isn't good for fuel atomization.

80# seems like an awful lot of injector even for a turbo build, unless you're making wild power or tuning for E85. I'm guessing somewhere in the 1000hp @ crank neighborhood is what 80# will support even on stock fuel pressure (but depends on what pressure the injector is rated for.)

Heads look really nice btw. I've always been amazed how spotless they come out every time I've taken one to a machine shop.
 
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About $500. Man they were dirty. I also had the bright idea to degrease them myself and in the process left one head outside figuring rain wouldn’t matter. Lol I was wrong. Rusted the valve seats. So I had the machine shop do all. I laid out all valves and was just gonna have the machine shop surface them and I was going to lap valves myself. But all in all the final product is even better.
That is a good price! Around here expect almost double that, I am just trying to get a feel for price difference in other parts of the country.
As far as your injectors go 850cc approx 80lb is way way to much, for 400 BHP, 270cc approx 25lb (85% duty cycle) is all you need on a NA V8.
2V turbo engines benefit from a straight shot injector pattern while NA a nice atomized pattern is best, it helps prevent cylinder wash down and oil dilution with fuel.

On a V8 each cylinder is producing 12.5% of the power on eg a 4cylinder each hole is making 25% and would need a much larger injector and so on. Do not use those Deka injectors, they are serious rubbish, I see those, old Rochester/Delphi Multec 1, Magneti Marelli and more than 50% of the time out of a set of 8 3 or 4 of any of these will be crap and not usable.

I don't sell huge performance injectors anymore, it is a real Pandora's box I rather not deal with but I have contacts who do. PM me when you need them I can hook you up with one of these guys.
 
That is a good price! Around here expect almost double that, I am just trying to get a feel for price difference in other parts of the country.
As far as your injectors go 850cc approx 80lb is way way to much, for 400 BHP, 270cc approx 25lb (85% duty cycle) is all you need on a NA V8.
2V turbo engines benefit from a straight shot injector pattern while NA a nice atomized pattern is best, it helps prevent cylinder wash down and oil dilution with fuel.

On a V8 each cylinder is producing 12.5% of the power on eg a 4cylinder each hole is making 25% and would need a much larger injector and so on. Do not use those Deka injectors, they are serious rubbish, I see those, old Rochester/Delphi Multec 1, Magneti Marelli and more than 50% of the time out of a set of 8 3 or 4 of any of these will be crap and not usable.

I don't sell huge performance injectors anymore, it is a real Pandora's box I rather not deal with but I have contacts who do. PM me when you need them I can hook you up with one of these guys.
Thank you for that info! So I have a set of stock 5.3 injectors and looking up online 01-07 are 25.7LB injectors. I guess I could use these?
 
Thank you for that info! So I have a set of stock 5.3 injectors and looking up online 01-07 are 25.7LB injectors. I guess I could use these?
If it is only making 400 BHP or approx 340 whp or less then sure, no problem, how much HP is has I have no idea. You could use 32lb, 36lb, 42lb or whatever depending on the HP and the tuning of the engine. The flow you see listed is what the injector can flow static, in other words wide open usually at 43.5psi.
Keep in mind the fuel pump may need to be upgraded when going with larger than stock, pressure also plays a big role in how much the injector flows.
My advise would be to put this car or the engine alone on a dyno with the stock injectors and see where they are at. Member Clinebarger has done tuning on these engines I believe you may want to reach out to him also.
 
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