TMS Iron 408. L92 heads or CNC ported ls3 heads?
#1
TMS Iron 408. L92 heads or CNC ported ls3 heads?
So this Friday I will likely be purchasing a 408 from Thompson Motorsports. I have had this planned for a long time now and I was planning to just go with a stock set of l92 heads, but after speaking with Aaron again today I am thinking about going with a ported set of ls3 heads that should make about 35 more rwhp. Do you think the 35rwhp is worth the $800? I mean everybody puts fast manifolds on for the same price and often don't see the same gains. So my thinking is instead of wishing I had more power later just going ahead and go for the cnc ported heads? Give me your opinions.
#5
I read a few test's and they seemed to be neck and neck. And the cathedral seems to be more expensive once you start going ported, no? Not to mention I can get an ls3 intake, injectors, rails, and 90mm tb for much less then what a fast manifold for cathedral cost's alone.
#7
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#9
#10
I think the more I read on cathedral vs rectangular port the less I know lol. What I do know is ls3 cars seem to run pretty damn well and ls3's with a cam make around 500rwhp. I have a little more stroke then an ls3 and with a big cam and some cnc'd ls3 heads I don't see why it shouldn't put down 500+rwhp. Find me a set of ported cathedral heads for the same price as the cnc ls3's also? Arent they more pricey? And like mentioned before I can get an ls3 with rails and injectors a lot cheaper then what a cathedral setup is going to cost me... If I had an unlimited bank account I might think about a highly ported cathedral setup..
#12
I made 505 with a 402 and patriot stage 3 heads. Which are just stock 317 castings ported. That was through a 9" with 4.11 gears, 325/50/15 drag radials, heavy clutch setup, and 1 3/4 pace setters. So I guess it's all in how you look at things.
I just know that you see more cathedrals getting down the track faster as well.
But hey if you want to just have 500whp it's cheaper that's cool too.
I just know that you see more cathedrals getting down the track faster as well.
But hey if you want to just have 500whp it's cheaper that's cool too.
#13
Right on blk00ss, we've all got different view points. Its not lost on me that dyno numbers are sometimes arbitrary numbers used as a proxy for performance.
I picked up l92s for $400, therefore I decided to got that route which is in line with my primary premise about price.
I picked up l92s for $400, therefore I decided to got that route which is in line with my primary premise about price.
#14
I made 505 with a 402 and patriot stage 3 heads. Which are just stock 317 castings ported. That was through a 9" with 4.11 gears, 325/50/15 drag radials, heavy clutch setup, and 1 3/4 pace setters. So I guess it's all in how you look at things.
I just know that you see more cathedrals getting down the track faster as well.
But hey if you want to just have 500whp it's cheaper that's cool too.
I just know that you see more cathedrals getting down the track faster as well.
But hey if you want to just have 500whp it's cheaper that's cool too.
#16
my 427 stroker made 560rwhp/500rwtq. had a sdpc C&C'd ls3 head. they were like 1500 with the rockers. think they flowed around 360cfm.
I don't think anyone will argue that a trickflow 245 or 260 head is a lot better then a ported ls3 head. but theres a pretty big price difference. specially with the YT rockers too.
I would atleast go with the ls3 valve vs the l92 for weight, specially if you plan on spinning it to 7k.
I don't think anyone will argue that a trickflow 245 or 260 head is a lot better then a ported ls3 head. but theres a pretty big price difference. specially with the YT rockers too.
I would atleast go with the ls3 valve vs the l92 for weight, specially if you plan on spinning it to 7k.
#20
i believe there is some variables to keep in mind for example the drive train, car weight , aerodynamics all of these come to play a roll.
i made 510 rwhp through dana s60 (9.75'' gear) with very similar build using stock ls3 injectors and i can tell you that between 6000 rpm to 6800 the motor were pushing the injectors to 94% duty cycle on the dyno and even to 96% on the street as you can notice the 2% difference between the dyno and the real world as the dyno will only see the drive train loss but on the street the weight and the aerodynamics will give there contributions.
i am keeping those injectors maybe for a year or so.
and i can see that your combo home is a vette so i wont worry about it much
Good luck with the build !
i made 510 rwhp through dana s60 (9.75'' gear) with very similar build using stock ls3 injectors and i can tell you that between 6000 rpm to 6800 the motor were pushing the injectors to 94% duty cycle on the dyno and even to 96% on the street as you can notice the 2% difference between the dyno and the real world as the dyno will only see the drive train loss but on the street the weight and the aerodynamics will give there contributions.
i am keeping those injectors maybe for a year or so.
and i can see that your combo home is a vette so i wont worry about it much
Good luck with the build !