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Adding cam and heads to my LS1 04 Vette. I bought some 243 cores and plan a full valve job, and pac1218 spring to match my cam. I am curious about the cost/benefit of cnc porting the heads at my modest power goals.
Im retired and this is my daily low mile grocery getter. I want good driving characteristics for local stuff, and then some hard pull to 5200-5500rpm for an occasional rip. I’m shooting for 400-ish rwhp and strong midrange. The plan is to keep the stock manifolds.
Is it worth the expense of having them cnc ported to gain 20-30 fwhp? You said it was a daily and if it were me I'd spend the money elsewhere such as in the exhaust. Put that money into some TSP 1 7/8 headers and their true dual exhaust system.
if you plan to do some 6500 to 7000 rpm pulls then yes
Thanks! No plans for anything that high. No track use of any kind. I mentioned that to the guy at Cam Motion who help me set up the specs.
At 5500 in 3rd gear I’m looking at low 80’s mph, which is pretty sketchy on a surface street. I usually do a rolling start in first and stab it, wind up 2nd, run up to mid 70s in third before easing back. That baby rip still uses up a stretch of pavement, it’s kinda fun, but it won’t get me in too much trouble.
A freeway on ramp may see 3rd top out, but I’m not in favor of entering traffic doing 90ish either.
You’ll get great results from a great valve job. Porting them is good for max effort builds, when your looking for an extra bit of power. You’ll find far more better results with aftermarket castings if your interested in going that route. A fast intake and larger throttle body will do more for you than ported 243’s will by themselves. Camshaft is best bang for the buck. DO NOT overlook what a good tune can do for you also. It’s not uncommon to find 20+ hp in a good tune. Have the heads milled for a bump in compression if you live in an area that has compatible fuels available. Compression is torque and torque is fun.
I didn't see it mentioned, but a bit of power can be had by bowl blending (or pocket porting) which gets rid of the ridge just below the valve seat as it enters the port.
Between that and the aforementioned quality multiangle valve job the heads will be much closer to being optimal
Ported heads are a no brainer if your serious about getting the most from the combination.
They will make more power everywhere and allow you to make big power with a small street friendly camshaft
But doing things right even porting stock heads adds up quickly.....alot of machine work, cnc porting labor, aftermarket valves and springs
You really could be closing in on the cost of my 223 heads done in an aftermarket casting that will smoke a factory ported OEM head in airflow and performance
This is an old thread and the costs have gone up some but they are still an excellent value
Cost wise, I’m pretty much locked in to the 243’s, but you definitely have me seriously considering going beyond a regular valve job and perhaps even a cnc port. Frankly, the cnc porting and valve job combo may be the most cost effective.
Texas Speed seems to be a popular destination, but I’ve run across some others, such as Total Engine Airflow. I looked at your website, but didn’t see this offered. If I overlooked it please let know.
My 2 cents... I don't see the point in any intake improvements if no improvement in exhaust. What is the benefit in improving breathing if you ain't improving exhaust to exhale...
As for heads, there are pretty but pricey heads out there, but my home ported 243s have gone 10.80s in a full weight 4th gen LS1 Camaro with a 230-236 cam, Fast 102 set up, Headers with good exhaust, 3600 stall, 4.10s, Bogarts and a Badass Tune.
Stock 243s or 799s are good up to 600 lift. I would definitely use Cometic .040 gaskets to improve quench and compression.
But you don't want to rpm much, and I can't stress enough how much Headers and a good flowing exhaust will be your best bang for the buck performance and efficiency wise.
My 2 cents... I don't see the point in any intake improvements if no improvement in exhaust. What is the benefit in improving breathing if you ain't improving exhaust to exhale...
As for heads, there are pretty but pricey heads out there, but my home ported 243s have gone 10.80s in a full weight 4th gen LS1 Camaro with a 230-236 cam, Fast 102 set up, Headers with good exhaust, 3600 stall, 4.10s, Bogarts and a Badass Tune.
Stock 243s or 799s are good up to 600 lift. I would definitely use Cometic .040 gaskets to improve quench and compression.
But you don't want to rpm much, and I can't stress enough how much Headers and a good flowing exhaust will be your best bang for the buck performance and efficiency wise.
I was hoping to avoid headers, but agree there is serious hp there. In any case, that’s a step beyond my current project; heads. I’m retired, and need to pace spending a bit, so your point is well taken. Maybe bank the extra $400 for porting toward some SE headers later on.
As far as the heads, my cam is at .587 lift, and have no plans/desires to rev higher than 5500. Still, there’s plenty of fun for my tastes in that range. 👍
Im planning my upgrades around the 15-80 mph rip when there’s an available stretch of road, or on ramp. Not interested in melting Michelins or ventilating trans/rear end, lol. Just some exhilarating put you back in the seat acceleration.
Yes! Ported 243 or 799 heads will help that power under the curve and carrying power out after peak tq/pwr. You'll be glad you did it, even with a small cam.
In my experience, even with a baby cam, ported heads added power everywhere. I wouldn't run an NA 5.7 without them, but that's me.
I previously had a Cam Motion "Torque Titan" 218/226 .595/.587 116+4 in my 5.7 LS1. I ran it with CNC ported 241s. It was a very smooth combo and suitable for a daily if you're not interested in rpm.
In my experience, even with a baby cam, ported heads added power everywhere. I wouldn't run an NA 5.7 without them, but that's me.
I previously had a Cam Motion "Torque Titan" 218/226 .595/.587 116+4 in my 5.7 LS1. I ran it with CNC ported 241s. It was a very smooth combo and suitable for a daily if you're not interested in rpm.
Thanks! That cam is very similar to mine. Appreciate your feedback. 👍
Seems like a large cam for something that supposedly won't see more than 5500rpm. It's not even close to peak hp until well after 6k.
Think you'd be better off with SDPC's LS6 Powermax. Early IVC for building mid-range torque and long exhaust duration to help the exhaust side breath with manifolds.
Seems like a large cam for something that supposedly won't see more than 5500rpm. It's not even close to peak hp until well after 6k.
Think you'd be better off with SDPC's LS6 Powermax. Early IVC for building mid-range torque and long exhaust duration to help the exhaust side breath with manifolds.
Opening up the heads to increase volume and air flow for larger cam and then choking it with a factory exhaust system just dosen't make sense when you could probably get away with a cam swap and milling the heads for a compression bump to achieve the results you seek. I'd determine my P-V so I knew how much I can get away with on the heads.
Already have the cam and heads, so I’m sorta locked in on those. Headers are not in the budget at this time; maybe later, hopefully later, but not now.
I truly appreciate the range of perspectives that have been offered. They’re all helpful in deciding my steps going forward.
If you have additional thoughts on the porting please join the discussion.
Already have the cam and heads, so I’m sorta locked in on those. Headers are not in the budget at this time; maybe later, hopefully later, but not now.
I truly appreciate the range of perspectives that have been offered. They’re all helpful in deciding my steps going forward.
If you have additional thoughts on the porting please join the discussion.
Having used a very similar cam, CNC ported 241 heads and a small exhaust on a 5.7, I'm going to go against the crowd and say that I think it will work. I would port your current 243 heads and fit. With your listed expectations being reasonable, and a Corvette being a light car, it should be good. If it were me, I would still fit a mild exhaust to this combo, but you can try it. You can change the exhaust later if needed.
You should check the ads and car shows. A lot of guys have switched to turbo from N/A engine. What that means is they have a good used exhaust system laying in the garage getting stepped on. Ask around.
07-04-2023, 02:48 PM
243 Porting Needed for Mild Cam ? 
