706 Heads Rule?! (706 vs 241 vs 317 vs 799/243)
12-25-2017, 02:38 PM
#1
706 Heads Rule?! (706 vs 241 vs 317 vs 799/243) Did a search and didn't see this posted:
http://www.hotrod.com/articles/surpr...der-head-test/
I did notice that the 706s were carrying the power well past peak, likely due to the lighter valves.
http://www.hotrod.com/articles/surpr...der-head-test/
I did notice that the 706s were carrying the power well past peak, likely due to the lighter valves.
12-26-2017, 06:54 AM
#5
Restricted User
If you head flows enough for your combo, going to a better flowing head will yield marginal results, sometimes even killer torque AND power. You can definitely go with too big of a head and hurt your setup overall.
The 706s are a good example. They flow well enough for most 5.3s so going to a better flowing head with a larger chamber just ends up causing power losses because compression becomes the deciding factor.
The 706s are a good example. They flow well enough for most 5.3s so going to a better flowing head with a larger chamber just ends up causing power losses because compression becomes the deciding factor.
12-26-2017, 08:52 AM
#7
If you head flows enough for your combo, going to a better flowing head will yield marginal results, sometimes even killer torque AND power. You can definitely go with too big of a head and hurt your setup overall.
The 706s are a good example. They flow well enough for most 5.3s so going to a better flowing head with a larger chamber just ends up causing power losses because compression becomes the deciding factor.
The 706s are a good example. They flow well enough for most 5.3s so going to a better flowing head with a larger chamber just ends up causing power losses because compression becomes the deciding factor.
The above test definitely didn't choke out the heads with a crap intake manifold or tiny headers, and the valve events favoured the small exhaust ports with a wider split than traditionally recommended for cathedral port heads.
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12-26-2017, 01:35 PM
#11
Restricted User
Results would have been a little different on a 6.0, and likely much different if you added a 4" crank to said 6.0.
But for the average 4.8/5.3 build, very relevant. CFM demand isn't that high. Even the stock heads are able to keep up with it. Therefore, compression is the deciding factor.
12-26-2017, 02:02 PM
#12
I wouldn't have been as surprised in the small difference in power if it had the stock cam and intake, nice to see that they were that close with a decent size cam and a 102. And the compression helps, but the compression isn't that much different, difference is only what .3-.5 or so? iirc it's .5 difference on a 5.7
12-26-2017, 02:28 PM
#15
We started offering affordable mls gaskets for them for good reason BUT when you look at the flow numbers that went with that test...then its just a tad off. So it should be taken with a grain of salt really.
Esp on an engine with huge injectors for no real reason and no accy etc etc.
Esp on an engine with huge injectors for no real reason and no accy etc etc.
12-26-2017, 04:58 PM
#16
We started offering affordable mls gaskets for them for good reason BUT when you look at the flow numbers that went with that test...then its just a tad off. So it should be taken with a grain of salt really.
Esp on an engine with huge injectors for no real reason and no accy etc etc.
Esp on an engine with huge injectors for no real reason and no accy etc etc.
12-26-2017, 05:00 PM
#17
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LS9 is used for boost bc it has more layers then a standard MLS. Standard MLS should be available for all engines, or worse case you could use a 5.7 gasket on a 5.3 if need be.
12-26-2017, 05:08 PM
#18
Well you're right about plenty of 4.8/5.3 builds but IMO nobody is gonna run an LS3 type (E/I split) cam, a FAST 102 intake, and low compression on a small engine without boost. And whatever flywheel horsepower it did make can be dropped by 50 simply because of the water pump, alternator, power steering, air conditioning (perhaps) and an exhaust system capable of keeping officer Bigfist off your backside.
12-26-2017, 05:09 PM
#19
We have a thread about em here
Pic on customer engine also
Last edited by tech@WS6store; 12-26-2017 at 05:15 PM.
12-26-2017, 05:12 PM
#20
Well you're right about plenty of 4.8/5.3 builds but IMO nobody is gonna run an LS3 type (E/I split) cam, a FAST 102 intake, and low compression on a small engine without boost. And whatever flywheel horsepower it did make can be dropped by 50 simply because of the water pump, alternator, power steering, air conditioning (perhaps) and an exhaust system capable of keeping officer Bigfist off your backside.