Hello, I have a L92 that will be a N/A street/strip build in a 67 Chevy II. I was looking at the summit cam https://www.summitracing.com/parts/sum-8702 The RPM range says 2500-6500 on summit racing but in their catalog for single plane intakes it says 3500-7000. I want the RPM range to start around 2500 due to the fact that it’s not a dedicated track car and I want it to come on early for street use.

I was also looking at this comp cam that’s on a 113 LSA which seems like a fuel injected LSA to be honest so I’m not sure about it. https://www.summitracing.com/parts/cca-54-470-11

What’s needed to get 600hp at the crank? Will this parts combination get me over the HP goal? The engine is apart so I can make changes to get to there. I’m used to some surging down low with a large cam and a manual transmission. I’m not driving around parking lots at 5mph.

Dome -2cc pistons I’ll keep the quench tight and aim for around 11.2-11.5 compression to stay on pump gas
Stock bottom end
823 heads not milled 70cc chambers but can mill them if need be
1.8 full roller rockers
850 holley double pumper?
Edelbrock 71197 dual plane manifold
2” or 1 7/8” headers?
3.73 rear gear
Manual transmission
Car will be almost 3,000 pounds without me in it

 

I think that’d do it. My LS3 made about that (471 whp) with a much milder cam. I have Mamo heads as well, but I suspect those are helping the midrange more than the top end, compared to LS3/L92 heads.

 

The camshafts you mentioned might do it with some REALLY good cylinder heads. Maybe look into a single plane intake manifold too. If my cyphering is correct, you'll need around 530 wheel hp to get you 600 at the crank. A carbed 600 hp 6.0L is going to be fun getting things right with fueling and ignition timing.

 

Single plane intakes suck on the street, period. You'll want that dual plane at minimum, and I'd urge you to consider EFI instead of a carb. I gave up on carbs 26 years ago and have never looked back. If you HAVE to use a carb, just get a vacuum secondary carb and tune it correctly. A double pumper is a race carb, and you said that this is primarily a street car. If you have the engine torn down, the easiest way to hit your power goal is to build it into a 416 stroker. 823 heads, even CNC ported, will not get you there without more cubic inches under them. Also, there's no need for 1.8 ratio full roller rockers on an LS. The factory rockers with a trunnion upgrade kit are far better than most aftermarket units. My LS3 made 466 RWHP with just a cam, 1 7/8" headers, and a ported rod mod LS3 intake. That's around 540 at the crank with a manual trans. I don't think there's a set of heads out there that could gain me 60+ HP in order to crest 600 crank HP, unless I wanted to put in a monster cam and a single plane intake and spin it to 8000+. Mine is a street car too, I like having power down low. So, for you to do what you want ( 2500 RPM + powerband and 600 HP ), you're going to need to increase cubes or install a roots style blower kit on it. In addition, there is no such thing as a "fuel injected LSA", and LSA is a meaningless number on it's own. You have to factor in intake and exhaust duration numbers in order to determine overlap, and overlap has a huge influence on how a camshaft behaves. A cam with 200/205@.050 duration and a 108 LSA will idle a lot smoother than a 242/246@.050 with a 113 LSA, because the latter has more overlap even though the LSA is wider. My LS3 sounds absolutely nasty at idle and it's got a 113 LSA.

 

Change of plans on the build after talking with some people and reading the comments. I’ll just cut some weight on the car to compensate for less hp. No big deal. How’s the drivability with the EPS cams 230/238, 234/236, and 236/248 on 109-110 LSA’s +4 maybe? I don’t want a mild steady lope cam. Looking for a hot street setup. When I look into cams in the mid 230’s duration I’m seeing cams starting around 3500 RPM but they’re all on 113 LSA’s. If I get them ground on a 109 or a 110 +4 since I’m carbureted won’t that have it come in maybe 800 RPM earlier? I always thought 4 degrees was around a 400rpm difference in the curve. 3500 is too high for street use to me even with a manual and that sounds like more of a max effort strip car.

Here’s the thing. I’m used to larger cams in smaller cubic inch engines with first gen SBC’s but I’ve never ran an LS. For example, I have a 327 with a 250@50 on a 104 LSA with 11:1 compression on the street with 4.11’s and I’m fine with it. Also have a 383 with a 236/242 on a 110 LSA with 10.5 compression. LS efficient headflow clearly don’t need as much duration to make power.