Ported 243s vs. untouched L92s on a 408
06-06-2010, 10:03 PM
#1
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Ported 243s vs. untouched L92s on a 408 I'm agonizing over cylinder head selection for 408-416 stroker build. I'm doing this on a budget and already own a pair of 243 LS6 heads and a pair of bare L92 heads. I'm going to use one of the set of heads I already own so aftermarket heads are not an option. If I use the 243s, I'll have them ported. The L92 heads I'd probably use as is.
Absolute peak numbers aren't the most important to me because the motor will be going into a street car that I occasionally open track on road courses. Intuitively, I would have thought ported cathedral heads would make more mid-range power and more torque than L92s, so I was leaning towards having my 243s ported and using a FAST intake. Then, while researching my decision I ran across this article which really surprised me-
http://www.carcraft.com/techarticles...ild/index.html
Untouched L92s made more overall torque than both untouched and ported 243s. Even after reading thread after thread about L92s while researching my decision, I was still surprised to see those results. Does that surprise anyone else? Anyone care to offer their thoughts on ported cathedral heads with a FAST intake vs. stock L92s and a L76 intake for the above mentioned application?
Absolute peak numbers aren't the most important to me because the motor will be going into a street car that I occasionally open track on road courses. Intuitively, I would have thought ported cathedral heads would make more mid-range power and more torque than L92s, so I was leaning towards having my 243s ported and using a FAST intake. Then, while researching my decision I ran across this article which really surprised me-
http://www.carcraft.com/techarticles...ild/index.html
Untouched L92s made more overall torque than both untouched and ported 243s. Even after reading thread after thread about L92s while researching my decision, I was still surprised to see those results. Does that surprise anyone else? Anyone care to offer their thoughts on ported cathedral heads with a FAST intake vs. stock L92s and a L76 intake for the above mentioned application?
06-07-2010, 07:57 AM
#2
I polished the exhaust runners and knocked down the valve bosses in the exhaust and intake runners for my 418 ls3 heads. Took maybe 6 hrs.
Price? a few sanding wheels and a dremel.
Flow? who knows.
power? stupid.
Price? a few sanding wheels and a dremel.
Flow? who knows.
power? stupid.
06-07-2010, 08:06 AM
#3
My experience is with road racing LS1 & LS6 motors in 2800# stock cars on
a limited budget. Not an engine builder......just owner/driver.
Since it is a street car that will be occasionally road coursed and you are
on a budget, I think the wise choice would be the unported L92's.
I think they will make the power and torque you want and have room
for improvement later.
Both the street and road course racing LOVE torque.
Was talking with Tim Schwanke (Schwanke Racing Engines) about their similar (but non stroker 6.2) ASA Transcontinental series motor. Seems they are making some serious power and torque with a surprisingly mild tune.
a limited budget. Not an engine builder......just owner/driver.
Since it is a street car that will be occasionally road coursed and you are
on a budget, I think the wise choice would be the unported L92's.
I think they will make the power and torque you want and have room
for improvement later.
Both the street and road course racing LOVE torque.
Was talking with Tim Schwanke (Schwanke Racing Engines) about their similar (but non stroker 6.2) ASA Transcontinental series motor. Seems they are making some serious power and torque with a surprisingly mild tune.
06-07-2010, 06:05 PM
#4
Probably good with either one. For continuous rpm on road courses I would like the sodium exhaust valves and the lighter intake on the 243 heads. Off course you can put the lighter valves in the 92s also.
06-07-2010, 07:13 PM
#5
well, the L92's flow about what a good set of ported 243's do...stock...not to mention the big 2.165 (? i think) intake valve will be awesome with the 4in+ bore. if you got the L92's run them. not to mention you can probably sell the 243's for 4-500 bucks for either some porting...machining...valves, springs....goodies, etc. for the L92's.
they're pretty much the best bang for the buck for 4in+bores.
they're pretty much the best bang for the buck for 4in+bores.
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06-15-2010, 06:57 PM
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Depends on who ports em. If your comparing them to garbage *** Patriot then dont. Heres some numbers from Advanced Induction:
Overall power will depend on what type of setup and what cam you'll use. 243s allow donkey dicks, LS3 heads are stingy on PTV clearance.
Since its a fresh build I say go with the LS3 heads. Later on have them done up wild. This is unless you have a end goal. People build for the biggest HP then end up blowing the tires off all day so the most may not be the best. Build what you can USE for the best price.
:cents:
Overall power will depend on what type of setup and what cam you'll use. 243s allow donkey dicks, LS3 heads are stingy on PTV clearance.
Since its a fresh build I say go with the LS3 heads. Later on have them done up wild. This is unless you have a end goal. People build for the biggest HP then end up blowing the tires off all day so the most may not be the best. Build what you can USE for the best price.
:cents:
06-15-2010, 07:35 PM
#12
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Depends on who ports em. If your comparing them to garbage *** Patriot then dont. Heres some numbers from Advanced Induction:
Overall power will depend on what type of setup and what cam you'll use. 243s allow donkey dicks, LS3 heads are stingy on PTV clearance.
Since its a fresh build I say go with the LS3 heads. Later on have them done up wild. This is unless you have a end goal. People build for the biggest HP then end up blowing the tires off all day so the most may not be the best. Build what you can USE for the best price.
:cents:
Overall power will depend on what type of setup and what cam you'll use. 243s allow donkey dicks, LS3 heads are stingy on PTV clearance.
Since its a fresh build I say go with the LS3 heads. Later on have them done up wild. This is unless you have a end goal. People build for the biggest HP then end up blowing the tires off all day so the most may not be the best. Build what you can USE for the best price.
:cents:
I've lost count of how many L92 and stroker related threads I've read trying to decide which way to go. The conclusion I've come to (and I certainly may be wrong) when comparing well ported 243s vs. stock L92 heads on a 408-416 stroker, their dyno numbers are very, very similar. However, the L92 seems to make their numbers with less cam timing. That could be an important distinction because I have to pass Kali emissions testing.
