chief455

iTrader: (21)

this car with ported stock heads and unported intake made 580rwhp at 10psi

I changed to ported AFR heads and long tube headers this year.

I am keeping the 58mm twin bore BBK tb for easy street tuning.

227/239 at .050", .560/.577" lift, 114LSA cam

Street car looking to get the best out of my combination this build.

Any point to paying for a 'ported' LT1 intake?

not much plenum volume or runner area to increase I can see -

will the blower just push air right through an LT1 intake? Will the 58mm tb be my limiting airflow factor anyway?

worthwhile to seek a 'well ported' intake from the usual guys names in here?

Anyone making 600+ rwhp forced induction with an LT1 intake?

I'm an old 4 barrel carb, high rise single plane intake muscle car guy - need new school real user advise.

thanks!

MasterTomos

iTrader: (15)

I know there has been some turbo guys that just use the factory ported intake. Port matching the factory intake may be a good, cost effective option, but a lot of guys do single planes as well for bigger builds. It's really up to you.

What I would do personally, is wait for some of the "big boys" to respond on here, and I'd also give some places like maybe Advanced Inductions, Elliot Portworks, Speed Inc, maybe TPIS, ect a call and see what they'd recommend, but definitely weigh out the pros and cons of ease of tuning, cost effectiveness, ect.

Sounds like an interesting build btw...pictures?

OutlawZ

iTrader: (4)

If it was me i'd single plane it... I guess I could be considered one of the big boys..... There are guys who have gone over 600RWHP with the LT1 intake but i think you could unleash more power with a traditional single plane setup for EFI. There are about a million threads about the conversion. You could use the opti or scrap it and go with a rear mount distributor like alot (including me) have done....you'd have to reroute your blower tube to go into some type of carb hat or intake elbow...

chief455

iTrader: (21)

great feedback,thanks!
I have no budget left for changes more than a few hundred bucks. I am disabled, have to pay by the hour for labor, and the longblock is ready to install. No time now for combo changes.
I have 35 years of race cars on the street - I want a true street car that has sick power.
I lowered compression from 9.2:1 to 8.4:1 with the AFR heads to reduce risk of detonation and just get more airflow out of my DISC at 10psi than the stock castings allowed.
Also - I'm more about maximizing my current (or close) set up, because it was already silly fast and reliable on the street - where it will be driven.
My goal and basic combination is set:
1. be able to dial in my current tune via Tunercat with minimal tuning skills
2. enjoy the benefit of throttle body fuel injection in factory form = reliability
3. I have LTCC so my opti is just a sensor to trigger = reliability.
4. I have a TH400 and 9" rear already = reliability
5. my fuel system is done at twin 255 in tank Walbros with a Hobbs switch. stock lines and rails w/60lb injectors
6. The car MUST retain factory A/C, cruise control and full stock interior
7. My exhaust MUST be reasonably quiet with 1-3/4 long tubes, y-pipe and single crossover muffler
8. max RPM will be based on the cam = ~ 6300

I've crossed the line toward 'race' in 4th gen f-body before and did not like the result. The appeal of these cars is the high power ability in an easy to drive, stock looking platform.
I've had '60s muscle cars - done with that.

Back on topic - can a 58mm tb and LT1 intake support 6300 rpm@10psi / over 600rwhp?
Could it actually be a choke point - or just leaving some more power untapped?
I can go the ported intake route, that would be it - but will that gain me enough to be worth $250-$350?
Otherwise I bolt my old intake on and it is what it is. Budget for more change is not here right now - no monoblades or single planes in my wallet
Who has a stock intake with a turbo or supercharger? What say you?
thanks!

OutlawZ

iTrader: (4)

I have neither a stock intake nor a monoblade but I can tell you this. My old motor with a lightly ported intake and a 58mm throttle body with good heads/cam on a 355 ci shortblock made 422 RWHP.... Your compression will take a good chunk off that but considering about 20 hp per psi roughly you will need to make about 400hp to achieve 600hp with the 10psi. I think it's doable....

Since we're talking rear wheel I think 550RWHP is more likely but that's still an assload of power for a rock solid reliable car...

tt383lt1

iTrader: (3)

a stock lt1 intake manifold ported can hold that horse power but idk about 600whp on 8:4.1 compression y so low with that low of boost?

BIGCAT7274

I am still running a ported lt4 intake. What you have will get you real close to your goals. Your injectors look a little small for the job.

speed_demon24

iTrader: (6)

You're going to cancel out a ton of the gains you were going to see form the heads by lowering the compression that much. 9.2:1 is way more than safe for 10psi in an lt1.

tt383lt1

iTrader: (3)

is your 383 forged bottom end? if so push more boost. and what are you pushing a turbo or supercharger?

Blackbirdws6

iTrader: (7)

You can check out my build for details but I'm running a ported stocker with ~15lbs on a F1-A. My restriction is the small twin intercoolers from procharger at the moment. Lowering your compression and using the better flowing heads will drop your boost but your power should be similar. Up the boost and start seeing the real gains. A single plane would be better but likely not worth the $ if you are not looking for every last but of power. Ported stock intake has served many very well.

96capricemgr

iTrader: (1)

9.2 was plenty low enough, 8.4 was a mistake.

Far as 600rwhp though an LT1 intake, the Donovan block 96 Impala that is approaching 160mph at full weight uses an LT1 intake. That car is WAY beyond 600rwhp.
Now I know he does jump through a lot of hoops to get cylinder balance dialed in and I think he made the plenum a little bigger at the rear, but this thing is making more than 50% more power than you are discussing.
Pretty sure it has a 58mm TB too, and I know it still has an opti, OEM computer, 4L60E and a lot of other parts people want to swap out at half his power.

moehorsepower

iTrader: (3)

will the blower just push air right through an LT1 intake? Yes
Will the 58mm tb be my limiting airflow factor anyway? No



Anyone making 600+ rwhp forced induction with an LT1 intake?
I made 722 RWHP with LT4 Heads & Intake @ 15lbs




[QUOTE=OutlawZ;16135812]If it was me i'd single plane it... I guess I could be considered one of the big boys..... There are guys who have gone over 600RWHP with the LT1 intake

^^ He is correct

quik95lt1

iTrader: (7)

i wouldn't be afraid of a ported LT1 intake........nothing wrong with it capable of well in excess of 600rwhp under boost as moe said above.....i was running 10.6x's at over 127mph NA with an LT1 intake myself and AI ported two years ago.......with the 6300rpm max you are running and a street minded intention i think youd be crazy to run a single plane on it......

RealQuick

iTrader: (14)

Lloyd Elliott will fully port your intake for ~$200. Worth it IMO.

I agree with not running a single plane with that cam... not enough rpm to see benefits I would think.

GM PHASST

Dale Baseman's impala ran an epoxy modded lt1 intake with an opti and stock ecu. His car did low 10's and dynoed over 600rwhp.

GM PHASST

U def could get some power back by raising ur compression back up. Since we have reverse flow cooling systems lt1's do a better job at starving off detenation than traditional sbc's.

Dave357LT1

What does epoxy modded intake mean?

LT1 POWR

iTrader: (4)

I've got a similar setup and I have a Holley single plane, just to be different. I originally had an edelbrock Vic Jr that I modified by shaving down the front coolant housing, but it seemed like everyone was using an edelbrock, so I went with a holley. Everything still fits under the stock hood too. I've got a forged 9.2 compression 383 with CNC Brodix heads and 10psi through a TC78 making 600hp and 600ft/lbs through a conservative tune, 2800 stall 4L60E and a 12 bolt. I also went with the 24X conversion since I already had EFI Live. I think 9.2 is very conservative on the compression. If I did it again, I'd probably do at least 10 something, bigger injectors and E85, although I think my current injectors will support E85. Also I'm only spinning to 5600 rpm which is way lower than I expected. I was wanting to build the motor to spin to about 7000, but I guess my valvetrain wasn't up to it.

SS Aleks

The lt1 intake port matched is plenty. As said before, boost is simply a measure of restriction. By improving the head flow your boost will be lower. I don't know too much about the various procharger blowers, but I assume you could change the pulley for a bit more flow without over cooking the supercharger. Sounds like a cool project.

MasterTomos

iTrader: (15)

^many people don't understand that boost=restriction. They always figure less boost will yield less hp. Take it from SS Aleks...I think he knows a thing or two about forced induction builds Hows that coming btw?