Why 6.0s are so thirsty?
Thread Starter
TECH Veteran
Joined: Sep 2014
Posts: 4,893
Likes: 703
From: Mississippi
Ive compared quite a few ls3 dynos vs some more heavily cammed and headed 383s and i can say i really dont see that correlation you are making.
Its very very hard to compare apples to apples on any of it because most people are talked into larger cams on 383s and even heads but still dont make the output youd expect.
Found an ls3 swap in a gto with the hot cam and then a 383 with tfs 220s and a vrx5 fast 102/102 in a 240sx. Not really 100% apples to apples, but the 383 is a pretty expensive build vs the ls3 with headers and cam.
Made same peak tq numbers and the ls3 had slightly better numbers before 4k. The larger cam of course took off on the top end.
A direct comparison would be great, but i think either one would accomplish the goal...and a 4.060 lq4 would be way less $$$ overall invested.
Man id LOVE to see some real world results from both of these combos to prove what is what.
I guess the only real way to tell down low is on a chassis dyno and with a long enough gear to get a clean pull but not lug the drivetrain on the dyno.
The only way to compare down low would be possibly from scan of airflow or maybe hpts calculated tq parameter. Other than that how can you tell?
If you guys can come up with some combos based off of a 372 (4.040) vs a true 383 that arent 2k heads etc throw them at me and i will take them in to consideration for a test I am thinking about running soon. ONLY those 2 engines and using either the stock truck intake, tbss, or the new dorman. I dont think ill have enough time for all of them but pick 1. Then maybe just some brand new off shelf 243s?
Throw your ideas out.
Its very very hard to compare apples to apples on any of it because most people are talked into larger cams on 383s and even heads but still dont make the output youd expect.
Found an ls3 swap in a gto with the hot cam and then a 383 with tfs 220s and a vrx5 fast 102/102 in a 240sx. Not really 100% apples to apples, but the 383 is a pretty expensive build vs the ls3 with headers and cam.
Made same peak tq numbers and the ls3 had slightly better numbers before 4k. The larger cam of course took off on the top end.
A direct comparison would be great, but i think either one would accomplish the goal...and a 4.060 lq4 would be way less $$$ overall invested.
Man id LOVE to see some real world results from both of these combos to prove what is what.
I guess the only real way to tell down low is on a chassis dyno and with a long enough gear to get a clean pull but not lug the drivetrain on the dyno.
The only way to compare down low would be possibly from scan of airflow or maybe hpts calculated tq parameter. Other than that how can you tell?
If you guys can come up with some combos based off of a 372 (4.040) vs a true 383 that arent 2k heads etc throw them at me and i will take them in to consideration for a test I am thinking about running soon. ONLY those 2 engines and using either the stock truck intake, tbss, or the new dorman. I dont think ill have enough time for all of them but pick 1. Then maybe just some brand new off shelf 243s?
Throw your ideas out.
- 372ci @ 10.1 compression
-243 heads with pac springs
-tbss intake
-1 5/8 long tube headers
-212/218 565/580 lift 111+3
I know a RESPECTED head porter that port heads for living. He told me in this application a simple bowl job and exhaust porting would help the motor out tremendously. And he can do the porting on the heads less than what it cost for any CNC job available....
I would hope he could do it for quite a bit less than a cnc job. The benefit of a CNC port job they are usually hand ported then well tested and proven then made repeatable via CNC programming.
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Ive laid out the specs for my test that meets all the criteria. Really though if you want ported heads why shy away from lift? Even .600 lift? Makes no sense. Seems backwards.
Ill try to get both engines done soon, but since this is a side pet project i cant guarantee a month.
6.0 blocks are pulling quite a premium one week before race wars....so maybe i can throw in a 3rd budget option. We shall see.
The graphs will have to settle for roughly 2500+ on the dyno stuff probably.
As far as headers go, most of the "budget" ones are 1 3/4 but alot are stepping up. Ill likely run Dynatech since they are quality without such a high price.
Ill make a thread about it some time soon.
Ill try to get both engines done soon, but since this is a side pet project i cant guarantee a month.
6.0 blocks are pulling quite a premium one week before race wars....so maybe i can throw in a 3rd budget option. We shall see.
The graphs will have to settle for roughly 2500+ on the dyno stuff probably.
As far as headers go, most of the "budget" ones are 1 3/4 but alot are stepping up. Ill likely run Dynatech since they are quality without such a high price.
Ill make a thread about it some time soon.
TECH Senior Member
Joined: Jun 2016
Posts: 22,298
Likes: 3,619
From: Central Cal.
I have always been of the belief, "the more lift the better", within reason of course. When building, say a 5.3 for fairly mild street use with 243/799 heads, is .600 lift still beneficial in spite of the potential "abuse" of the stock rocker/valve stem? I just wonder where the "common sense" barrier is, or if there is one. Just a little late-evening thinking out loud.....
To be honest ive disassembled entirely too many engines and i can say very VERY little have shown guide wear. Stock or otherwise. Ive seen more spit up rocker bearings and fooqued lifters and spun cam bearings and broken springs (stock 5.3s) than worn guides. High lift cams or not. Bronze guides are a diff story. Low miles, high miles, some that looked like coal on the inside. Even if they has some wear, a small amount of knurling fixed em.
It may be a good theory but ive never seen it play out in huge fashion in th real world. The ones that i have seen (ironically) are 243s. No 799s though.
Nearly any of the cams out there have more than .600 lift on intake or exhaust or both.
It may be a good theory but ive never seen it play out in huge fashion in th real world. The ones that i have seen (ironically) are 243s. No 799s though.
Nearly any of the cams out there have more than .600 lift on intake or exhaust or both.
Thread Starter
TECH Veteran
Joined: Sep 2014
Posts: 4,893
Likes: 703
From: Mississippi
Who offer the cheapest CNC job on the market?
Anyway check this PROVEN combo out... 5.3 block.
Block: Stock (Bored to 3.902)
Anyway check this PROVEN combo out... 5.3 block.
Block: Stock (Bored to 3.902)
Crank: 4340 forged 4.0-inch stroker-Procomp ElectronicsRods: 4340 6.2-inch, Procomp ElectronicsPistons: 21cc dish forged piston, Probe Industries (3.902 bore)Cam: COMP XR275HR .566/.568 lift split, 222/224 duration split, 112 LSA Heads: TEA Stage 1 CNC 5.3LIntake: Stock TB: Accufab 78 mmHeaders: QTP 1¾-inch long-tube Peak Power: 506 hp at 5,700 rpmPeak Torque: 503 lb-ft at 4,700 rpmTorque Curve: Exceeded 475 lb-ft of torque from 3,800-5,500 rpm
Last edited by Tuskyz28; Oct 15, 2017 at 09:40 AM.
Thats cam only 6.2l power...and way low on the hp considering. Total combo cost for cost youd wind up with the same price even.
Still that torque peak is way too late even for a lower cr setup with 21cc dish pistons.
Looks like a way early magazine build really esp finding a set of qtp headers.
That engine wasnt made to pull, likely mad for boost with the cr imo. It does make nice power breathing through the straw of a 5.3l truck intake of course, but even those longer runners and long stroke cant keep the powerband down. It should be shifted down at least 400rpm. The trucks peak at 4k rpm in stock form in both lq4 and lq9. 5.3s are same way.
Obviously this is why the big blocks are king of gas stump pullers and why cid is the way to go, but nearly all the big blocks have way lower ci than what is normally targeted. Im sure there is a good reason.
Still that torque peak is way too late even for a lower cr setup with 21cc dish pistons.
Looks like a way early magazine build really esp finding a set of qtp headers.
That engine wasnt made to pull, likely mad for boost with the cr imo. It does make nice power breathing through the straw of a 5.3l truck intake of course, but even those longer runners and long stroke cant keep the powerband down. It should be shifted down at least 400rpm. The trucks peak at 4k rpm in stock form in both lq4 and lq9. 5.3s are same way.
Obviously this is why the big blocks are king of gas stump pullers and why cid is the way to go, but nearly all the big blocks have way lower ci than what is normally targeted. Im sure there is a good reason.
Ill try to get both engines done soon, but since this is a side pet project i cant guarantee a month.
6.0 blocks are pulling quite a premium one week before race wars....so maybe i can throw in a 3rd budget option. We shall see.
The graphs will have to settle for roughly 2500+ on the dyno stuff probably.
6.0 blocks are pulling quite a premium one week before race wars....so maybe i can throw in a 3rd budget option. We shall see.
The graphs will have to settle for roughly 2500+ on the dyno stuff probably.
As far as headers go, most of the "budget" ones are 1 3/4 but alot are stepping up. Ill likely run Dynatech since they are quality without such a high price.
Ill make a thread about it some time soon.
Ill make a thread about it some time soon.
Yeah, something to be said for matching the headers up to the motor's characteristics. I was just saying in general, the label has less to do with the performance. You get the bang ditching the stock manifolds.
If you pay attention to computer hardware, same sort of thing. theres a much bigger bang going from platters to solid state storage than there is arguing between which SSD is better.
Wasn't really getting into which size primary to run. I mean, hell the old SBC used to run 1-5/8
If you pay attention to computer hardware, same sort of thing. theres a much bigger bang going from platters to solid state storage than there is arguing between which SSD is better.
Wasn't really getting into which size primary to run. I mean, hell the old SBC used to run 1-5/8
Well the reason i said dynatech is they offer both y pipe and dual exhaust config for the mid pipes, are super high quality, dont command the premium, fit perfect every time, and of course we sell em. They are exactly what i would look at for any truck build. And ive literally installed em all.