old absolute speed stage 2 853's any good?
12-26-2009, 02:53 PM
#1
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old absolute speed stage 2 853's any good? how about these? Ive got about 4 different pairs of heads im kicking around right now. 2 pair of these, the MTI's and another set of 243's with a 3 angle valve job and some bowl work. All within the same price range.
So, to you guys who have actually dealt with these heads, how did they perform?
So, to you guys who have actually dealt with these heads, how did they perform?
12-26-2009, 03:40 PM
#2
1st What engine are you running? I had my 243s done by AI, 215cc with the 3 angle valve job and CNC'd for my 02 LS1 C5. They perform beautiful with the cam I am running. Its and Ed Curtis cam close to the MS3 in lobe separation but higher int/exh. If you do go with the 243s I suggest going with the hollow/sodium filled valves. The lighten up your valve train and will have less issues. The larger valves net 2 - 3 hp more but then you can rub into clearance issues. I am also running a Vararam VR-b2 and that is a hell of a game changer also.
12-26-2009, 04:01 PM
#4
If its a bottom end LS1 the best heads are the 243s for flow, the 853s you will need larger valves to see better performance and you are stuck with a 2.02 intake and 1.60 exhaust. If you go any bigger you will see clearance issues with the valves. I have seen 853s perform but they are usually running 2.05 intake valves.
The other reason like stated before the lighter ls6 valves will help you reach your rpm power band quicker. I would compliment that with Yella Terra rockers if your thinking of aftermarket rockers but the stock ones are fine just buy a set of new ones. Specially with a cam in that range. Rockauto.com has them cheap as hell and the valves also.
I am shifting at 6800 with a 7000 redline through an A4 and am at 450/422 rwhp/rwtq with an E-85 conversion, my 243s and other accompanying performance mods on a stock bottom end LS1 so the heads do work.
Good luck.
The other reason like stated before the lighter ls6 valves will help you reach your rpm power band quicker. I would compliment that with Yella Terra rockers if your thinking of aftermarket rockers but the stock ones are fine just buy a set of new ones. Specially with a cam in that range. Rockauto.com has them cheap as hell and the valves also.
I am shifting at 6800 with a 7000 redline through an A4 and am at 450/422 rwhp/rwtq with an E-85 conversion, my 243s and other accompanying performance mods on a stock bottom end LS1 so the heads do work.
Good luck.
12-26-2009, 04:48 PM
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I know the absolute speed ls1 heads were claimed to flow in the 307 intake, 228 exhaust range. To me thats a damn good flow number. Not to mention they arent a HUGE runner head. A stock LS6 set wont flow this number. Now, I do also know that with a good valve job, and bowl/blend work they CAN reach close to this number, if not exceed it. My only issue is im on a budget here, and im not really sold on the entire "cnc" only head porting. I think there are many out there that can do just as good if not better by hand. Just tossing around ideas out there. Not to mention I can get em for CHEAP.
12-26-2009, 04:58 PM
#7
I know the absolute speed ls1 heads were claimed to flow in the 307 intake, 228 exhaust range. To me thats a damn good flow number. Not to mention they arent a HUGE runner head. A stock LS6 set wont flow this number. Now, I do also know that with a good valve job, and bowl/blend work they CAN reach close to this number, if not exceed it. My only issue is im on a budget here, and im not really sold on the entire "cnc" only head porting. I think there are many out there that can do just as good if not better by hand. Just tossing around ideas out there. Not to mention I can get em for CHEAP.
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12-27-2009, 03:14 PM
#11
12-27-2009, 05:26 PM
#12
Old Absolute heads were 100% hit/miss. Where 1 set would do great and make good power, 1 set would make terrible power and have some kind of failure.
The only way I'd run an older AI head would be having it pressure checked by a machine shop, and replace ALL valvetrain components with new hardware that I know isn't going to fail.
The only way I'd run an older AI head would be having it pressure checked by a machine shop, and replace ALL valvetrain components with new hardware that I know isn't going to fail.
01-01-2010, 09:51 PM
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I have a set of these heads on my car that were bought in 2005. They have 2.040" I, 1.57" E valves. CNC'd and hand blended. 10.5/1 comp, not sure of the chamber size. I've compared my setup and times with similar setup cars and I think the heads perform on par if not better than average. Dyno and track times in sig.
Back in the day before AFR and TFS heads, these were making all the big numbers with LG cams like the G5X3 and G5X4.
Back in the day before AFR and TFS heads, these were making all the big numbers with LG cams like the G5X3 and G5X4.
01-01-2010, 10:25 PM
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Old Absolute heads were 100% hit/miss. Where 1 set would do great and make good power, 1 set would make terrible power and have some kind of failure.
The only way I'd run an older AI head would be having it pressure checked by a machine shop, and replace ALL valvetrain components with new hardware that I know isn't going to fail.
The only way I'd run an older AI head would be having it pressure checked by a machine shop, and replace ALL valvetrain components with new hardware that I know isn't going to fail.
