Ballistic Speed Small Bore LS3 vs GMPP LSX-L92 Small Bore heads
12-13-2013, 08:56 AM
#41
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I haven't really seen many people run the PRC Small bore LS7 heads much but maybe I'm looking in the wrong places. So what exactly does the whole raised runner do other than give airflow a more straight path to the cylinder? Or is that all it does. Also who would i have to contact to get a straight answer on the RHS small bore valve sizes?
Oh and RHS small bore ls7 heads vs TSP small bore ls7 heads which one would u guys think is the better head?
Oh and RHS small bore ls7 heads vs TSP small bore ls7 heads which one would u guys think is the better head?
12-13-2013, 09:26 AM
#42
I haven't really seen many people run the PRC Small bore LS7 heads much but maybe I'm looking in the wrong places. So what exactly does the whole raised runner do other than give airflow a more straight path to the cylinder? Or is that all it does. Also who would i have to contact to get a straight answer on the RHS small bore valve sizes?
Oh and RHS small bore ls7 heads vs TSP small bore ls7 heads which one would u guys think is the better head?
Oh and RHS small bore ls7 heads vs TSP small bore ls7 heads which one would u guys think is the better head?
12-13-2013, 11:38 AM
#44
FWIW: We dyno'd my 403 build with the stock LS3 intake and an hour later with a ported intake from Corey at LS2portworks. Peak was the same but picked up a couple in the middle. The LS3 intake as actually pretty good but it works better on smaller builds.
Just my $02
12-13-2013, 12:30 PM
#45
You do realize that a LARGE percentage of people use the wrong valve events or the wrong CR to make excellent power.
FWIW: We dyno'd my 403 build with the stock LS3 intake and an hour later with a ported intake from Corey at LS2portworks. Peak was the same but picked up a couple in the middle. The LS3 intake as actually pretty good but it works better on smaller builds.
Just my $02
FWIW: We dyno'd my 403 build with the stock LS3 intake and an hour later with a ported intake from Corey at LS2portworks. Peak was the same but picked up a couple in the middle. The LS3 intake as actually pretty good but it works better on smaller builds.
Just my $02
12-13-2013, 03:40 PM
#46
Depends on whats considered the "right valve events" and who is saying they are. Most use the LS3 cam shootout article as the standard which I think showed the potential for the heads but also through shade on further developement and thinking.
My camshaft events would be considered wrong by many because I found something out very interesting with testing. We used the wide splits and even the tight LSA's, they made nice pretty torque curves and dyno numbers but were not true performers at the track. I tightened up the splits and started going faster.
All I care about is going fast and building a fast car.
I am not building a car to go fast at the Texas mile, I wanna go fast from A to B(light to light, 1/8, or 1/4). not A to Z.
I'll let the bench racers admire pretty torque curves.
I consider whats right or excellent power by how fast the car is on the street and at the track, not necessarily by a dyno.
My camshaft events would be considered wrong by many because I found something out very interesting with testing. We used the wide splits and even the tight LSA's, they made nice pretty torque curves and dyno numbers but were not true performers at the track. I tightened up the splits and started going faster.
All I care about is going fast and building a fast car.
I am not building a car to go fast at the Texas mile, I wanna go fast from A to B(light to light, 1/8, or 1/4). not A to Z.
I'll let the bench racers admire pretty torque curves.
I consider whats right or excellent power by how fast the car is on the street and at the track, not necessarily by a dyno.
12-13-2013, 03:50 PM
#47
I don't have the money or the desire to test cam designs , but had a cam ground based on an engine an out fit built for the Engine masters Challenge. The idea was to use a short duration to trick the heads into making solid torque down low, and the hope was for the heads to carry the cam at upper RPMs. The LSA was kept tight to turn the power curve on with the big ports and it had to pull enough vacuum for my big brakes (16" at 850rpm idle). Its in a stock GM LS3 crate engine with a GMPP dual plane carb intake and Fast EZ EFI, well, because Im a computer idiot and am too tight to pay someone else to tune my junk, LOL. With 3.42 gears and a 2800 lock up converter in the 2004R trans, and Vintage air AC and power steering, it will cruise at 1700rpms without a sputter or surge and knocks down 20+MPG. On a resent trip to the track to play with the timing, it went 11.65 at 118 peddling and spinning for a 1.876 60 ft. Im sure it will trap 120+ with traction off the line. The cam specs are 220-230 at .050 on a 108+4 and 629 lift on both sides. I think the theory of short duration and tight LSA works very well on the LS3 heads, especially if you are putting something together that will cruise at low RPMs , but has a surprising punch when you lay on the load pedal.
Its in a 72 Camaro that weighs 3500lbs with me and a half tank of 93.
Its in a 72 Camaro that weighs 3500lbs with me and a half tank of 93.
12-13-2013, 04:06 PM
#48
I don't have the money or the desire to test cam designs , but had a cam ground based on an engine an out fit built for the Engine masters Challenge. The idea was to use a short duration to trick the heads into making solid torque down low, and the hope was for the heads to carry the cam at upper RPMs. The LSA was kept tight to turn the power curve on with the big ports and it had to pull enough vacuum for my big brakes (16" at 850rpm idle). Its in a stock GM LS3 crate engine with a GMPP dual plane carb intake and Fast EZ EFI, well, because Im a computer idiot and am too tight to pay someone else to tune my junk, LOL. With 3.42 gears and a 2800 lock up converter in the 2004R trans, and Vintage air AC and power steering, it will cruise at 1700rpms without a sputter or surge and knocks down 20+MPG. On a resent trip to the track to play with the timing, it went 11.65 at 118 peddling and spinning for a 1.876 60 ft. Im sure it will trap 120+ with traction off the line. The cam specs are 220-230 at .050 on a 108+4 and 629 lift on both sides. I think the theory of short duration and tight LSA works very well on the LS3 heads, especially if you are putting something together that will cruise at low RPMs , but has a surprising punch when you lay on the load pedal. Its in a 72 Camaro that weighs 3500lbs with me and a half tank of 93.
Its in a 72 Camaro that weighs 3500lbs with me and a half tank of 93.
12-13-2013, 04:54 PM
#49
I pedaled it for a solid second, after it broke loose and I got completely off the gas, then back on it. I lost a good amount of acceleration time in all that craziness . Easily enough time to pick up another 1 1/2 to 2 mph, IMO. Spring time will tell one way or the other. Ive done some front end work to get some weight transfer out of it. On the track trip I had Hotchkis 600 in lbs springs and KYB gas shocks. Now I have Moroso 212s and Bilstein drag shocks. The car separates much better now.
12-13-2013, 07:00 PM
#50
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Ok so since were talking about cams, what do u guys think of my current cam. Its a 236/242 @ 0.50 on a 113+3 LSA. I can't for the life of me remember the lift but i bet it isn't much. This cam was speced by the sponsor who i bought my short block and heads from. Im really learning a bunch from this thread so please keep it coming. The only thing I've noticed with my current setup is i don't have much torque down really low.
Heres a example, my house is on a hill. Where i park my car is perfectly level. In order for me to get to the street i have to go up my driveway which is about 30 yards and its pretty damn steep. When my car was stock i could just throw it in first and drive up it at about 1400 rpms. Now if I'm under 2000 rpms it will surge and stall. Then when i hit the gas it will light the tires up. Anyway is this what everyone is talking about when they talk about a intake runner being to big and lacking power down low?
Heres a example, my house is on a hill. Where i park my car is perfectly level. In order for me to get to the street i have to go up my driveway which is about 30 yards and its pretty damn steep. When my car was stock i could just throw it in first and drive up it at about 1400 rpms. Now if I'm under 2000 rpms it will surge and stall. Then when i hit the gas it will light the tires up. Anyway is this what everyone is talking about when they talk about a intake runner being to big and lacking power down low?
12-13-2013, 07:45 PM
#51
Ok so since were talking about cams, what do u guys think of my current cam. Its a 236/242 @ 0.50 on a 113+3 LSA. I can't for the life of me remember the lift but i bet it isn't much. This cam was speced by the sponsor who i bought my short block and heads from. Im really learning a bunch from this thread so please keep it coming. The only thing I've noticed with my current setup is i don't have much torque down really low.
Heres a example, my house is on a hill. Where i park my car is perfectly level. In order for me to get to the street i have to go up my driveway which is about 30 yards and its pretty damn steep. When my car was stock i could just throw it in first and drive up it at about 1400 rpms. Now if I'm under 2000 rpms it will surge and stall. Then when i hit the gas it will light the tires up. Anyway is this what everyone is talking about when they talk about a intake runner being to big and lacking power down low?
Heres a example, my house is on a hill. Where i park my car is perfectly level. In order for me to get to the street i have to go up my driveway which is about 30 yards and its pretty damn steep. When my car was stock i could just throw it in first and drive up it at about 1400 rpms. Now if I'm under 2000 rpms it will surge and stall. Then when i hit the gas it will light the tires up. Anyway is this what everyone is talking about when they talk about a intake runner being to big and lacking power down low?
12-14-2013, 02:26 PM
#52
On my setup, leaving power on the table was acceptable . Surging and bucking at 1700rpms with the converter locked wasn't. Im no expert, but have built cars for 28-30 yrs and the combo I have in my 72 Camaro is the best compromise Ive messed with. The tight LSA and short duration, along with the LS3 heads, makes the flattest torque curve of about anything Ive ridden in. The usable power starts right off idle and the rev limiter always catches me off guard at 7000rpms, because the engine doesn't feel like its done. Im not a big dyno guy either, as they do very little to show what the car/engine combo does dynamically . I will eventually dyno this one just because I am interested to see what the torque curve looks like. The engine I used as a reference for the cam we ground was a 408 with mildly ported exhaust ports, the gpmm dual plane intake and made 595HP at 6200 and 582TQ at 3200 on 91 pi$$ water gas. The kicker is that it made over 500ft lbs from 2500 to 6000. It ran a cam with 607 lift on both sides, 226-228 at .050 on a 108+6. That kind of low end torque ,that is still hanging in there past 6000, isn't seen often in the LS family. Usable torque with a tight converter and mild street gears, but the legs to buzz to 7K is exactly what the Dr. ordered for my mild street build.
12-14-2013, 03:13 PM
#53
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I see where u guys are coming from and i agree that track times and fun on the street are where its at. I need to keep reading up on a lot of the things u guys are talking about. U see this is my first car build so I'm just trying to learn all i can.
Now newschool72, was that 408 that u based ur cam off of in a magazine article cause id like to read up on it if it is.
So when u guys say tight LSA's would that be a numerically low number like 108 LSA is tighter than a 110 LSA?
Now newschool72, was that 408 that u based ur cam off of in a magazine article cause id like to read up on it if it is.
So when u guys say tight LSA's would that be a numerically low number like 108 LSA is tighter than a 110 LSA?
12-14-2013, 04:42 PM
#54
I see where u guys are coming from and i agree that track times and fun on the street are where its at. I need to keep reading up on a lot of the things u guys are talking about. U see this is my first car build so I'm just trying to learn all i can.
Now newschool72, was that 408 that u based ur cam off of in a magazine article cause id like to read up on it if it is.
So when u guys say tight LSA's would that be a numerically low number like 108 LSA is tighter than a 110 LSA?
Now newschool72, was that 408 that u based ur cam off of in a magazine article cause id like to read up on it if it is.
So when u guys say tight LSA's would that be a numerically low number like 108 LSA is tighter than a 110 LSA?
Yea, the tighter LSA is the smaller number. 108 is tighter than a 110.
12-14-2013, 05:04 PM
#55
http://www.popularhotrodding.com/tec...s/viewall.html
Here it is. Enjoy!! The principal of the short duration/tight LSA and the LS3 heads works in its simplest form, as in I didn't do any of the special prep they did. I just stabbed a cam in my engine(stock LS3) that used the same concept and it really does run fantastic for the" almost factory stock" drive ability. It really does cruise "stock like" at 1700rpms, but buzz to 7K effortlessly. With traction, my mild geared, tight converter setup should go around 11 flat at 120 in a 3500lbs car with AC and PS. Im thinking over a few ideas to maybe touch a 10.9x this spring, without changing anything engine or drivetrain wise.
Here it is. Enjoy!! The principal of the short duration/tight LSA and the LS3 heads works in its simplest form, as in I didn't do any of the special prep they did. I just stabbed a cam in my engine(stock LS3) that used the same concept and it really does run fantastic for the" almost factory stock" drive ability. It really does cruise "stock like" at 1700rpms, but buzz to 7K effortlessly. With traction, my mild geared, tight converter setup should go around 11 flat at 120 in a 3500lbs car with AC and PS. Im thinking over a few ideas to maybe touch a 10.9x this spring, without changing anything engine or drivetrain wise.
12-14-2013, 07:40 PM
#56
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http://www.popularhotrodding.com/tec...s/viewall.html
Here it is. Enjoy!! The principal of the short duration/tight LSA and the LS3 heads works in its simplest form, as in I didn't do any of the special prep they did. I just stabbed a cam in my engine(stock LS3) that used the same concept and it really does run fantastic for the" almost factory stock" drive ability. It really does cruise "stock like" at 1700rpms, but buzz to 7K effortlessly. With traction, my mild geared, tight converter setup should go around 11 flat at 120 in a 3500lbs car with AC and PS. Im thinking over a few ideas to maybe touch a 10.9x this spring, without changing anything engine or drivetrain wise.
Here it is. Enjoy!! The principal of the short duration/tight LSA and the LS3 heads works in its simplest form, as in I didn't do any of the special prep they did. I just stabbed a cam in my engine(stock LS3) that used the same concept and it really does run fantastic for the" almost factory stock" drive ability. It really does cruise "stock like" at 1700rpms, but buzz to 7K effortlessly. With traction, my mild geared, tight converter setup should go around 11 flat at 120 in a 3500lbs car with AC and PS. Im thinking over a few ideas to maybe touch a 10.9x this spring, without changing anything engine or drivetrain wise.
12-14-2013, 07:55 PM
#57
That was a good read and very enjoyable. Thank u for digging that up. So if tight LSA's and and rectangular port heads do well together why doesn't everyone use tight LSA'S? Is there a big draw back to them? The only thing i can think of would be a lower power band.
Look at the dyno sheet on that 409 D&A built. The power band isn't narrow, like you would expect with a cathedral port engine and a very tight LSA. It makes 500+ ft lbs from 2500 to 6000 ! Im convinced its a way to use the LS3 heads that keeps the power in the area that 99% of your driving will be in with a street driven combo. And it requires a tight stall and mild gears to take advantage of it. Perfect of a street car. That D&A engine would go into the 10 sec zone easily with a 2500 stall and 3.42-3.55 rear gears.
12-19-2013, 09:28 PM
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With the LS7 valve spacing, it could fit a 4" bore but it is way too close to the bore walls. Forget shrouding, you could actually have the valves contact the cylinder walls. However, I think those valve sizes are actually a typo and the small bore versions actually have a 2.10" intake valve. The LS7 ports are already tall, and now to have a raised runner LS7 is pretty badass. I'd be interested to see how the raised port actually matches up to an OEM manifold with the port almost 1/4" taller than an OEM head.
I couldn't say who actually casts them, but I want to say that they were actually Dart's design, but were discontinued and RHS picked up the rights to produce them. I think they've done the same with several Dart BBC heads as well and released them under the RHS name. Don't quote me on any of that, that's just what I think I've read but I don't really know for sure.
I couldn't say who actually casts them, but I want to say that they were actually Dart's design, but were discontinued and RHS picked up the rights to produce them. I think they've done the same with several Dart BBC heads as well and released them under the RHS name. Don't quote me on any of that, that's just what I think I've read but I don't really know for sure.
12-20-2013, 07:05 AM
#59
U sir are correct. I called RHS the other day and they said out of the box they are ready for a 2.100" intake valve. I forgot to ask about the exhaust valve size though. The valve sizing numbers on there website are the max sizes u can have the head machined to accommodate is another thing they told me. They also said that they recommend a valve job before u assemble the head, so who would one send these heads to for a nice valve job?
Chris Frank (Frankenstein Racing Heads) would be another, or Rick McConathy (Slick Rick Racing Heads).
12-20-2013, 09:05 AM
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I greatly appreciate the recommendations and ill have to get some quotes.