Don't forget the LS1 cars have been running 12 oh's to 12 twenties with just a few bolt-ons. Take an auto car and follow the recipe: Vig TC and shift kit, Midlength or LT headers, catback, computer tune, air lid. I've seen the same combo swapped into a few 3rd gens that are running 11.8-9s. It's a little depressing to see all the mods I have done and the times I've acheived all the while the LS1 cars are right there with bolt-ons plus camshaft. It's all the same basic principle though. Making an engine more efficient. We have to do more mods as the LS engines are starting out in a much more efficient form.

 

The 200cc Dart Pro Ones have had some cleanup work done to the intake ports. They were advertised as 64cc combustion chambers. They were actually measured at 69cc. I had to have them flat milled as much as possible and was able to get them down to 65cc.

Regarding the LS1. Yes it is much easier to get results with bolt on modifications. The point we were making is your not just going to bolt one in and run 12 flat with out some work and money. For one thing you would need a custom header to fit the 3rd gens.

With the new heads now available such as from AFR the perfomance potential is now very close to the LS1. With the advancement in cam designs the gap has also closed quite abit.

At the 2008 F-Body LA Invasion we were not all that impressed by the general performance of the 4th Gens compared to our moded TPI cars. We were holding our own quite well on the same track and the same weather conditions. The question was being asked "how do we make those cars run that fast?" I think they thought we would be easy pickings. We will do even better this year.

 

Cam, yes the gap is very narrow, but I think the heads are still behind. It's the valve angle and the intake port design that keeps the LS heads ahead of the previous design. Have you seen any SBC, without going completely radical, make 450rwhp like a cammed 5.7 LS1 is capable of? How about 480-500rwhp from a heads/cam setup just as the 5.7LS can do? It's just sickening! And these are streetable combo's here. And with the right drivetrains, suspension, dieting...mid 10's from these setups as well. The big problem with most LS1 cars you see, is the owners forget about setting up the rest of the car properly when making the 400+rwhp that's so easily acclomplished. Part of the equation to getting a car down the track is gearing, TC if an auto, suspension tweaks/additions, etc....otherwise you won't be using all that power. 400rwhp 6speed with factory 3.42 gears is a complete dog! You might see mid 12's! But do a rear end with the right gearing and a little suspension and mid 11's is now possible. Also, my post was referring to the $5K that was getting tossed around. I think it's doable for that kind of money.

BTW, I can't say I've heard of these termination boxes you speak of. Would you mind touching on that as it sounds interesting!

 

Here is a thread I started on the exhaust termination boxes. Hopefully it will answer your questions.

https://www.thirdgen.org/forums/exha...ion-boxes.html

As to the horsepower the LS1 motors are making for those interested take a cruise over to LS1 Tech and look in the Dynamometer Results and Comparison section to see what these motors are making.

 

Here's a link to the David Vizard article that 1989GTATransAm refers to in his Exhaust Termination Box thread.

http://www.superchevy.com/technical/...exh/index.html

 

not to turn this into a lsx thread but yes i've seen some LT1 type setups make mid 400's whp fairly easily with todays heads. AI has LT1 motors going as fast as the LS1's. 475-500whp is doable with a built LT1 and big cam that will rev. My car was 400whp and not very radical. Better head with better intake manifold and better cam i could have seen 440-450 and keep it streetable

And those mid high 400's to near 500whp 5.7L lsx's arent that streetable... those motors lope like a son of a *****. Most 'streetable' 402 lsx builds make 500-510 whp even tho they are capable of 550.

But yes, the LSx head valve angle is really what the big advantage is

 

Yeah, we are kind of straying from the thread here! Oh well, it's just discussions cause we like talking about what we love! And yes that "streetable" term is completely different from person to person so we might avoid that topic. The LT1's are requiring more than what's needed on an LS1 to make the same kind of power. As I said before, it usually involves going pretty radical and/or going larger cubic inches to acheive that power. I should have been a little more clearer on my comparison. Basically what can you get out of a SBC/LT1 with just a cam and bolt-ons vs an LS1 with the same mods. Now throw heads on that combo and see what happens. No matter how radical or not you go with either, the LS1 will always be up about 50plus hp if the combos are basically in the same ballpark. A good street cammed LT1/6spd makes around 350rwhp. LS1/6spd will see 390-400rwhp. And where would our anchient setups be to compare.... We won't go there!

 

There were some dyno results from a 370ci LT1 with AFR heads that I can't find the link to for the moment. Anyways he put down 470 or so rwhp. The cam was not radical at all. I thought those were excellent numbers for a very streetable combination using the latest in head and camshaft technology.

Maybe Orr remembers it.

 

I found this article about a 370CI LT(?) w/ AFR heads. Somewhere around 550 chp.
http://forums.corvetteforum.com/engi...afr-heads.html

 

Yep, that is the guy. Here is a link to the thread I was thinking about. Thanks Skinny Z for the reminder. Very impressive numbers and a well thought out motor.

http://forums.corvetteforum.com/c4-t...-dry-sump.html

 

wonder how much dry sump adds? 210's with that cam i would not have guessed anywhere near that power. I would have guessed 210's with a 240/243 cam that i was planning on running this year for 450whp but dry sump must have added a good bit

 

Guys I'm not saying they can't make the power. The point I was making was IF all things are SIMILAR, the LS engine will always make more power. As in Cam only vs Cam only, or C/H vs C/H, Radical vs Radical. Usually about 50plus. I've seen the larger LT1's make awesome power. Friends car with 408 solid roller, worked AFR210's, DFI, custom intake, etc...thru an auto made 500rwhp. Now it makes about 1000-1500 depending on what speed the hair dryers are blowing!!

 

That 370 was carbutraited!!!! C'mon guys!! Although it probably makes close to that with the FI.

"The shop didn't have an FI controller, so we had to run it with an LT1 carb manifold (smaller ports than my heads, but this was really just for break-in and mechanical check) and a Demon 1000CFM carb."

 

From the chasis dyno pull.

"Intake:
Ported LT4
42lb injectors
58mm throttlebody"

Yes the engine dyno was done carburated but the chasis dyno was with the FI system.

 

Why not go there? A long-runner TPI seems to be limited to 320 RWHP we have found with our testing. But if you use a short-runner TPI intake, 350+ RWHP is not difficult at all. And it will require custom chip tuning, same as an LT1 or LS1 combo.

LS1's are nice, but I'd rather keep a TPI engine in my thirdgen.

 

Ok, if you want to compare apples to apples, then put a set of "18 degree" heads on a regular SBC and see what happens.

 

Oops....guess I should have looked at the second link. I was wondering where you got the 470 from.

 

That sounds more like a heads, cam, and intake?? What can you get with just a cam only? Not much, cause our intakes and heads suck!

 

So how would that work on a cam only vs cam only? I was trying to prove a point mod for mod. That's not really apples then. An apple to apple change would be to add an 18 degree head on the SBC and then an 11 degree on the LS. Or can we not change the heads on the LS since your changing heads the SBC?

 

Don't get me wrong guys....I love my TPI setup more than most LS combo's. It has tons and tons of torque which makes for a blast on the street, easier launches, and it's challenging! You can fart and get 400+ rwhp out of an LS1. Previous setups just take a bit more. It's the technology!

 

Fastest heads/cam stock internal 5.7 ls1 went 9.82 at 134 at 2858lb raceweight. something like a 5900 stall in a TH200 trans or something like that.
Dyno'd somewhere north of 460whp

But i dont understand why it only went 134. seems low for that hp and weight. I was around 520whp and 3450lbs and went 128.

Oh well, LS1 stock bottom end can hold more power than the weaker LT1 so it seems. Most stock cube heads/cam LT1's will make close to 400whp and call it a day as more revs will lead to rods seperating. But its POSSIBLE to make near 450+ with a solid roller but i dont know if it will hold

apparently the fastest stock shortblock LT1 is only 1/4: 10.88 @ 122.81. NOt even a solid roller cam car so who knows if anyone can or has beaten that. Not sureof the weight either. I did find a 10.89@128 with stock bottom end with unknown cam with LT4 ehads. Fastest cam only LT1 is not much slower at 11.16 at 119 or so.

LS1 is strong but proper 15-18 degree headed sbc's can run just as strong

 

Dang, I hadn't heard that. Congrats to that guy! The initial test car for the Thunder Racing TREX cam ended up going 10thirties at 13Xmph. It was a T56 car with stock internals somewhere around 3100lbs IIRC, stock internals, etc.... made 450-460 to the rear IIRC. Been several years ago.

 

I wonder who that was. There is guy down here that runs, or used to anyway, a cam only LT1 f-body that was running low 11's. I hadnt' been to the track in so long so I don't know where his car is at. He had some tricks up his sleeves though as he always hung around the stock eliminator cars/guys.

 

I'm a little late on this, but I'm going to have to disagree there. My 2000 did 479.7 RW to the wheels through stalled auto and a 4.10 rear. (347 ci) I daily drove it for months, it has great street manners. The cam is much smaller than you think, and I have puny AFR Mongoose 205cc runner heads. My car has only a slight lope, and delivered 16.5 MPG average - 90% city/10% highway.

 

.... but that is not a fair comparison though. SBC heads flow horribly from the factory in comparison, so why no just compare a 305-LG4 with an LS7 for that matter then? There is nothing magical about the LSX engine, it's just that they happen to flow extremely well from the factory. The cylinder heads that are available for the SBC to make them out perform the LSX are simply out of reach for most. If your going to compare engines, first equip the SBC with either set of these heads first, then lets see where the comparison goes from there;

SB2.2




Aero "Old Dominion" 32 Valve

 

I haven't spoken w/Joe Overton on the other boards in a very long time, but I'm pretty sure it was in the high ten second bracket, cam only LT1 that is. But we're talking extremely ported heads, intake and an excellent suspension setup. Not sure about the cars overall weight though....

Edit: Here's an updated list of some fast LT1's on LS1Tech;

http://www.ls1tech.com/forums/lt1-lt...1tech-com.html

 

It seems to me that if your are going to compare the cost of putting decent heads on an L98 versus just swapping in an Ls1 to a Third Gen, you have to also add in the cost to modify the Third Gen to make the engine fit. If you are going to change cylinder heads on the Ls1, then add in the cost of new head bolts/studs, since none of the hardware in an Ls1 is reusable. When you factor in the cost of an Ls1, cost to modify the Third Gen to fit it, and the cost of new heads and hardware if you change the heads, the L98 may or may not equal the La1 for power, but the L98 won't be as expensive to build as the Ls1. If the Ls1 you install needs a rebuild, not one bolt is reusable.

 

Oh. I wasnt paying attention. I thought it was the merits of a built TPI engine vs swapping in an LS1. I didnt notice the convo had drifted to cam-only setups.

Yeah our TPI heads suck compared to aluminum LT1 and LS1 stuff. Even the Corvette TPI heads suck.

If you want to compare an LS1 to a SBC you'd have to put the better heads on the SBC first, otherwise its like comparing a 386 computer to a new Pentium 4. After all, an LT1 or an LS1 is just a SBC with a better set of heads and intake.