NewSpin

So I know I want to swap an LQ4 into my 71Nova in the nearish future with a T-56 Magnum. I want to just run the stock long block with a cam and a carb + the MSD 6LS for a while, shoot for around 400+hp at the wheels. But my ultimate goal is 550+ at the wheels and moer torque. I almost definitely want to make it a 408 with ported stock heads, maybe some valve work, forged internals etc., 11:1 compression cap. I need to run on 91.
My question is can I meet my goals N/A with a carb or carbs (I kind of like the Holley dual quad intake...)
or do I need to bump up to forced induction?
If my calculations are correct I'd need about 650hp at the crank, is that about right or do I need more/less tp make 550+ at the wheels?
If I can do it N/A I would prefer that, and I'd like to make it a bit of a stump puller in terms of torque if I can.

Darth_V8r

iTrader: (4)

550 is doable with a 408. Now, 550+ with lots of low end grunt might put you with a roots type blower(not a snail or hair dryer). Trying to preserve low end torque is going to sacrifice power potential up top, which is where you get your HP numbers. A blower will give you both.

Tuskyz28

408ci
Afr 245 head
Ported fast 102mm intake at least
Custom 240s duration cam
Good brand 1 7/8 headers
42lb injectors
11.0:1 or more compression
#this combo will make 630 plus at crank around 6500 and 580 ft at the crank.

550 at the tire is roughly go be 620ish @ the crank...

NewSpin

Darth_v8r (sweet username btw) that's why I originally wanted a Procharger, use about 9.5:1 compression and spec everything for low end grunt and then run 10-15lbs for the top end. But now I'm thinking I shouldn't need that power for my goals (I want to be able to run mid 10s, don't need any more, but also be responsive enough for autocross and the like), but I'd still like some nasty low end
Tusky if I go n/a I'd like to stay carbed, I only want to go fuel injected if I end up with forced induction. Keep it simple stupid... etc

NewSpin

Also I don't want to go with a roots or screw blower, I'm going to have a short cowl/scoop hood (Harwood Protouring model) but I'm not gonna have quite that kind of clearance.

NewSpin

And I've seen a couple 408/Procharger combos that made almost 100ft-lbs more than the horsepower figure. That really appealed to me...
But I realize that might be more a function of boost than the hard engine specs

Tuskyz28

It can be done with a carb also..... won't be a issue there at all.

HCI2000SS

iTrader: (2)

You're gonna need more than ported stock heads though

NAVYBLUE210

550 RWHP more likely 640+Crank HP
MMS 235s with ported Victor Intake
850-950 CFM Carb
CAMMOTION LLSR Cam specced by Tony or Kip
My stab at it (no expert)
~ 245*/251*, LSA 114* +3* .680"/.650
1 7/8- 2" Step Headers X Pipe with min dual 2 1/2" exhaust.
MMS235s & Medium sized LLSR will allow decent low-end torque
And throttle response, valve control and decent lift will allow
Power to 7000RPM+ Should make 650+ crank, 550+ RWHP
That's a start and worth what you paid for it LOL!
Seriously Talk with Tony @ MMS and Kip @ CAMMOTION

NewSpin

Yeah I know a carb will work, just wanted to be clear haha
I've been thinking about heads but aftermarket ones are so expensive... I've seen a lot of people getting a heck of a lot out of stock ones both boosted and n/a, I know Lingenfelter does mail order porting and I liked the numbers their options had

NewSpin

Navyblue210
that's a bit more than I was looking for possibly haha
I dont I'd be able to afford Mast heads... I'd love some though for sure, but if I could get any I'd just get some Black Labels haha
Bit more header than I was planning on too, I was gonna go for 1-7/8"
And I don't want to run any crossover for a few different reasons, packaging etc
Also I want up to 65-6700rpm only, so I can keep an ideal power band and all. I'm not looking for a super high revving engine (not on this one, I WILL own a 67 Camaro with a built LS7 some day... IRS, ITBs, Nascar exhaust, the whole deal. Some day...)
For now I want a street capable car, but one that will maybe run mid 10s... or high 10s, we'll see
If my math is right my car will end up about 3100lbs with me in it (no rear seats, fiberglass hood, no inner fenders, no power steering or AC, no interior except dash, plastic fuel cell, etc), with the T-56 2.97 gearset and 3.70 rear gears what would it seriously take to hit 10s? On 275-295 drag radials at the most btw
And a bit of a driver mod if I do say so myself...

ombilaogha

which is where you get your HP numbers. A blower will give you both.

Tuskyz28

Mid 10s..... funny you mentioned that and the combo I gave you have been 10.80 @ 130 mph in a 4th gen SS car with no weight reduction (rapid motorsports). We all know 4th gen camaros are heavier than a 67-69 camaro. So you get you'll run a mid 10 easily due to less weight if you can stick the power to the ground.

NewSpin

Apart from the heads (aftermarket vs ported stock) and the fuel injection that combo is basically what I was thinking originally. I think I will check that out. I'm sure the carb vs Fast intake will make a decent difference.
Thanks for all the great replys

Darth_V8r

iTrader: (4)

Maybe I'm a bit outdated on FI technology. I tend to think of centrifugals as having lag like a turbo, and really kicking in strong around 3,000. Whereas, I tend to think of blowers as off-idle strong, and sort of hitting their maximum contribution around 5500 rpm or so.

The LS naturally wants to peak torque around 4800 rpm and HP at 6300 rpm, based on intake runner lengths, etc. So, if you run a centrifugal, you don't really address the low end, but you magnify the natural power you are already getting at the high end.

So, how this plays out when I've driven them is that the centrifugal feels like someone pressed a hidden nitrous button at 3K-3500 rpm. The blower feels like a bigger motor. And I get space constraints on that cowl. F bodies are the worst for that.

A possible compromise on that might be TT with some smaller turbos to spool up quickly, giving you more boost early on. gets expensive, though.

Now, you can get 550HP out of a 408 NA. You could get the stock square ports for better flow (and cheaper) than many ported cathedrals, but you'll lose a bit of low end torque and throttle response, and camming it can be a bit trickier. When you say "stump puller", I'm thinking you want your torque strong and available at 1500 rpm (like a truck pulling a stump). Is that what you're looking for?

Tuskyz28

Carb intake would be better in the higher rpm range over the fast.... where the fast will shine is in the low rpm range making a greater torque number earlier in the powerband.
Kinda a trade off either way it goes....

NewSpin

Pretty much, or at least if I can get close to that. I would like close to 400ft-lbs available from about 2,000rpm and up. I've seen it done before but those were engine dyno numbers, I also know the new Z06 does that (but it has a screw type blower, direct injection, and VVT)
I feel like going forced injection would almost be a little bit overkill for my goals, I'd like to explore all my N/A options first at least.
I can try and get tricky with gearing and the like, that's why I wanted the 2.97 gearset in the T56 vs the 2.64. I think I worked out it will behave like having 4:10s in the first few gears and then something like 3.23s in overdrive.

NewSpin

Tusky that's why I was considering the Holley mid-rise dual quad intake. It seems to give a really good compromise and I haven't really seem anything quite the same in terms of a small dual quad, not a high-rise or a tunnel ram

Tuskyz28

400ft lbs at 2000 rpm..... it can be done. It will take the proper cam selection along with a set of good heads. A set of great cathedral heads would be my recommendation over a set of rectangular port heads. I have my reasons why I said that. Reason one a rectangular port head is tricky to nail down.... where a cathedral head isn't as bad. Another reason I said that those rectangular port heads lacks big time in velocity. Poor exhaust side of the head is a big drawback there... such is the huge intake ports. Even a factory 317 truck heads out performs a LS3 head in the torque department to 4000 rpm. When choosing a cam don't cam it for sound/lope. Cam the motor to perform

A mid rise intake would be very interesting. Kinda having both sides of torque and horsepower. Win win situation.

NewSpin

I meant to say before that I want to stay with cathedral ports for those same reasons. And I already know it'll sound good with whatever cam I choose haha, I'll have long tubes, 3" piping, Carven R mufflers (if you haven't heard them check them out... they sound nasty on an LS), and Trans Am style side exits.
I was looking at Comp's LSR selection. I know a ton of people have had huge success with them, there were a couple in particular that seemed just right for what I want (~.600-625 lift, good LSA for the street and torque, and I plan on using their springs and retainers as well so everything should match nicely)
Super Chevy had a series with a progressive 5.3 build where they did a bunch of different configurations. One was a 383ci stroker and they were testing a single plane Victor intake with a 750cfm vs the Holley dual quad setup with 390s. The duals made only 1hp less I think and barely 6ft-lbs less peak to peak, but around 3000rpm it made almost 50ft-lbs more than the single plane. I like that.
Peak power was around 550hp I think
I'd maybe run dual 450s though, and I'd have about 0.5L more displacement as well, so I think if I ran enough compression with the right heads and cam I can do it.