Texhotrod593

iTrader: (7)

71 chevy

iTrader: (18)

"Since you cant dazzle them with brilliance, baffle them with(cough) B U L L S H I T".

LOL. youre a funny dude.

bottom line is stock ls1 heads on a 408 will make 1100 at 15 psi, "sonic choke as it relates to engines and intake ports" or not!

i dont understand your sonic choke (LMAO) but I do understand how to make 900 hp at 12 psi with factory stock 862s that dont flow worth a darn, on a 6.0

B'klyn9C1

Finally someone who have seen it both ways and gave an honest assesment!

I see in my poll so far unported heads is winning by a crushing landslide of 87% to 13%.

TurboMonte100

iTrader: (1)

While nick.celis made a good comment, there were a handful of other posts already that stated basically the same thing.

B'klyn9C1

Yeah you're right!! Thanks to all for your thoughts and comments.

The I noted Nick was that his experience was back to back unported and ported heads and he clearly stated the results.

hellbents10

iTrader: (10)

Show me your 408 with stock heads that makes 1100+ on 15psi lol!!!! That is a good joke but you need to lay off the hippie hay man. If you do get those super duper dyno numbers it better go 170mph through the traps at 3400lbs.

What does that 900hp 6l trap and what does it weigh? That will tell the true story.

71 chevy

iTrader: (18)

1100hp at 3400lbs will go 170mph???

ive never been that fast and I dont know, but reher morrison, which is one of the most respected names in the industry thinks it takes 1475hp at 3500lbs to go 170, so Im going to say that 1100hp at 3400 will NOT go 170mph. They list 1100hp at 3500 as 153mph.

I dont see you peddling anything so Im very surprised you would post misleading information.

as far as my combo, I listed the weight and speed in post 18. please tell me how much power Im showing

LS1NOVA

iTrader: (12)

71 Chevy, can you post the details on these 900-1100 combos, Im interested.

Texhotrod593

iTrader: (7)

yeah man maybe tell us how its done with pics and info on the kit rather than bashing some very well known members going VERY fast. I am also skeptical on a 408 @ 15lbs making 1100 even if you are talking flywheel. If that was/is true please share some info man! reason is the rest of us are sitting on 347/370/408/414 etc with stock heads and 15lbs only around 800+ fwhp.

Maybe you found a secret we all dont know?
Would be nice to share

EDIT: Btw OP I believe you should turn it up a little more than waste money on heads. Reason is that you are not wanting 1000+hp out of this setup and it will easily reach your goals with stock heads. Use your money on good set of tires or something else.

71 chevy

iTrader: (18)

1. I wasnt bashing hellbent. He is a well respected member and he has my respect too. I was just surprised that he would say 1100 would go 170 at 3400lbs.

2. where do I start?
a lot of people dont know how to make power, and a lot of people hamper their power production for such things as streetability etc.

how many people are running those junk air to air intercoolers that hurt more than help?

how many people are running restrictive intakes(i understand that hood clearance may be an issue but the if the intake is restricting power, it is restricting power.

how many guys do you see running pump gas and junkyard parts then having to run the timing down at 14° to get the thing to live. ask the fast guys like hellbent or andreas what timing is commanded on their systems at 15 lbs of boost.

how many guys are running a bunch of accessories off the crank?

how about combos where the turbo is strategically place to ingest the hottest air possible from the engine bay.

how many people are taking the 5" outlet of their turbo and necking it down to 4, or even 3 inches?

there are many ways to kill the power output of a combo, and unfortunately a lot of people are doing those things as routine.

patriotformula

iTrader: (28)

Just run stock unported heads and crank the boost up another pound or two. Just what I know from experience on that type of build.

typhoon1015

iTrader: (5)

Just to be clear, are we talking 900-1100hp at the crank or wheels?

I would run stock heads for now, get it running, and then next time the car is down swap out some ported stock castings if you desire more Hp for your goals. There are more important things to match up and worry about combo wise with turbos than ported/non ported heads that can make or break a build.

hellbents10

iTrader: (10)

1100rwhp Mustang 275 radial car on our dyno, 8.30@172mph. 347ci A2W 10:1 engine on 25psi with good heads and a single 94. Weight is around 3500 as it is still a street car.

Cal's Mustang 429ci High ports 1050rwhp 3550lbs true street champ 8.2x@165+mph. 10:1 A2A 23psi twin 76s

This is just a dynojet 248x that seems to run numbers the same as everyone else in MI.

The drag car with the ol 438 would make 1000rwhp at 15psi. 10:1+ compression TFS 235s, victor intake 105mm TB, solid roller 260ish@.050 with 25 degrees of timing. We raced it at 38-43psi to run in the 6s.

71 chevy

iTrader: (18)

i knew something was off. hellbent would never say a car would run 170 with only 1100 hp, at 3400 lbs.

turns out you were referring to rwhp and i was referring to flywheel hp.

so, here are my questions.

optimised combo, ie right cam, not knock limited, right timing, how much do you see a 408 with stock ls1 heads making at the flywheel on 15 psi? many on here want to know.

also, 117.4 eighth mile, 3000 lbs, per your calculator, how much power is that at the flywheel?

hellbents10

iTrader: (10)

10-4 71'

On alky with full timing and 10:1 compression prob about 1000fwhp. Typical setup with race gas and not enough timing about 850-900fwhp. After 15psi they will not pic up very well either, just not enough runner.

For example the 438lsx with 235s was picking up power like crazy going from 5-10 then 10-15 then 15-20, but after 20 it was slowing on power production and after 30 it was getting dismal. I think this was what Liljohn was referring to with the heads just being too small to really shine in the big hp area.

For a junk yard warrior though no reason to ever port the heads as the rods will bend before any other wall is hit for sure. Also putting aftermarket heads on engines with Chinese rotating assemblies is sort of the same for me.

71 chevy

iTrader: (18)

i agree. i just dont see the heads being a restriction under 1000hp.

im have a chinese rotating assembly for my next motor and im still staying with the junk 862s.

Wicked69

FWIW-71 Chevy has helped me a ton with my combo. My chevelle when it weighed in at 3870lbs with me in it, ran 118.42mph in the 1/8 rolling it off the line. This is a completely stock 5.3 with the cam in my signature, very conservative timing, on E85. The only thing I did to the heads was change the springs and used Ls9 Headgaskets. I hit that mph at 20lbs of boost.

Jamescassy

iTrader: (3)

Wow I needed to hear some of that !

handyandy496

iTrader: (9)

What are some of the current prices for cnc porting for n/a 243 heads.. Looking for the lowest price for a good port job.

1CAMWNDR

iTrader: (21)

Spend the cash on the right cam for the combo, and good valves and valve job.