5.3L AS heads questions and update after machine shop
06-27-2006, 07:34 PM
#1
5.3L AS heads questions and update after machine shop Okay, just got the heads back from the performance machine shop. Pressure tested well, no warpage, but I'm concerned: they cc'd at 66cc. That's no advantage! WTF? So I'll have the same friggin' compression ratio as the heads I currently have. That smokes ****. Anyone got any suggestions? Can I mill these bad boys? And how much? Will that change pushrod length? I'm so ticked now. I mean, I know the flow is much better, but this isn't what I was going for.
06-27-2006, 08:31 PM
#2
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They do perform, I didn't have mine cc'd but the chambers were milled quite a bit. Maybe you can run a .040 gasket and bring it up enough. That would add about a half a point.
06-28-2006, 06:14 AM
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Originally Posted by N4cer
Just thought a little... how much could I mill these without causing piston/valve clearance issues? Valves are:
Intake: 2.05
Exhaust: 1.57
Intake: 2.05
Exhaust: 1.57
How much you can mill will depend on the duration of the cam more than anything else. What cam are you planning on using?
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06-28-2006, 05:55 PM
#9
Bring me up to date, what are the stock 5.3's suppose to be? I have Absolute Speed Stg. 2 heads and my compresion is right around 11:1 w/ the factory graphite gasket. There was no porting in the chamber, just some basic cleanup and deburring. I also think Jay never milled them either, because I am set up to run 7.4 pushrods. The engine, after the head swap has always pinged like crazy in 6th gear under any load. Never did that with my factory 5.7 heads. So it definetly has more compression.
Did Jay port the chambers on those heads?
Did Jay port the chambers on those heads?
06-28-2006, 06:24 PM
#11
Originally Posted by DaleMX
Yup, I think it's to unshroud the valves.
Hard to see, but mine are basically untouched except for some minor hand work.
06-28-2006, 06:24 PM
#12
Yeah stock 5.3L is like 61.3cc. So he did a lot of chamber porting. I also think it was to unshroud the valves. So although compression is stock, the flow should be darned good.
How big can we go on the cam on this with these 2.05intake valves?
How big can we go on the cam on this with these 2.05intake valves?
06-28-2006, 06:31 PM
#13
Originally Posted by N4cer
Yeah stock 5.3L is like 61.3cc. So he did a lot of chamber porting. I also think it was to unshroud the valves. So although compression is stock, the flow should be darned good.
How big can we go on the cam on this with these 2.05intake valves?
How big can we go on the cam on this with these 2.05intake valves?
. With my 2.04 valve, he speced me a 230 size cam with a decent lift.(under .600) But that was right around when he went out of business, so I never saw that cam. 
I would contact some sponsors over there>>>, and they should be able to help you. I have a friend who had a car with a pair of stg 2.5 heads from Jay, and he had to grind reliefs in his pistons to run his cam. If you want, I will try to find out exactly what he was running.
06-28-2006, 06:52 PM
#15
I would think you would be fine with no mill for sure. But I would contact comp to see what they say since its their grind. I would even take a gander you could mill those suckers. Thats not a lot of duration, and duration is where you get into ptv clearance issuses.
06-28-2006, 07:24 PM
#16
Just got off the phone with Comp. They're saying I'm probably in trouble with this setup and will need to flycut, or at least SHOULD flycut to be safe. I have no clue about that. But maybe running a 7.35 pushrod instead of 7.4. That's an idea. Thoughts?
06-28-2006, 07:39 PM
#17
Originally Posted by N4cer
Just got off the phone with Comp. They're saying I'm probably in trouble with this setup and will need to flycut, or at least SHOULD flycut to be safe. I have no clue about that. But maybe running a 7.35 pushrod instead of 7.4. That's an idea. Thoughts?
06-29-2006, 11:38 AM
#18
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I'm running a TR230 with no problem whatsoever. With a 224 cam and less then .600 lift you have absolutely "0" worries.
Keep in mind that it's the duration that causes contact problems, not the lift and a 224 is a baby cam in an LS1.
Keep in mind that it's the duration that causes contact problems, not the lift and a 224 is a baby cam in an LS1.
07-01-2006, 09:05 AM
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Yeah, I can look at that chamber and tell its mid 60s in cc. The chamber has alot of work in it. I did a set of 5.3s for a guy that has the F13 cam and I milled em .018"(only reason for this is to get the chambers back to stock size after my work) and he didnt flycut.