Oddball cam/turbo recommendations
That's going to be a nice truck!! What you're asking about is pretty much exactly what my combo delivers. Wallace racing calculators puts it at about 800 crank and that doesn't factor in that it doesn't 60' great because it's traction limited and doesn't top end well due to terrible aero. On track tires it gets into boost before the throttle goes 100% . Cam and springs only 04 lq4 , so 9.4:1 compression, tiny cam motion 214/214 shelf cam . Idles with ~ 16.5 in vac. @ 725 rpm . Turbo was simple cast 7875 .96ar. Truck is over 4500 lbs when street driving, 4l80e , 3.73 and 30" tires would put it similar to yours without doing the math . It even drove well with 3.40 gears and stock converter, easily overpowered the street tires , more gear is not going help - just more spinning. Even in 4wd it would roast tires and possibly break stuff in first . If using pump gas I would say simple W/M kit with washer fluid, will add some safety. . Currently trying to control boost down to a lower level for street driving by switching to a 4 port from a 3 port and I also switched to a next gen billet 7875 with 1.25 housing and 9 blade vs 10 turbine in hopes to both make a bit more power and hopefully slow spool a bit so I might be able to floor it below 75 mph and not be a smoke show , can always hit scramble and add more power on the fly . What's the expected weight of this truck ? Combos that are good in 3500 lb cars might not be as good in a 5000lb truck
Exactly, Blazers are heavy - I'd say easily 5000lbs. I think I'll start with a 7875 .96ar (whatever VS's newest/best model is) and see how that works. Any low-overlap turbo cam would probably be fine but I'll call one of the cam shops just to be sure and go with whatever they tell me. I can fit a good sized A2A intercooler but if thats not efficient enough due to the low speeds of truck-driving, I can always add a little meth. A small 2" hotside crossover should help with spool and I'll let Circle D recommend the best stall speed. Sounds like you already have traction problems with a similar setup so this combo should get me there.
I'd spend a little coin on the IC as well, Treadstone, Garrett, Bell are all great and more importantly efficient.
I run an A2W in my streetcar and there is nothing better, a reservoir would fit in the bed quite nicely.
Fit the biggest 4" IC you can up front and you'll be fine, you've got a ton of surface area at the front of that truck, airflow will not be an issue lol.
I'd spend a little coin on the IC as well, Treadstone, Garrett, Bell are all great and more importantly efficient.
I run an A2W in my streetcar and there is nothing better, a reservoir would fit in the bed quite nicely.
I'd spend a little coin on the IC as well, Treadstone, Garrett, Bell are all great and more importantly efficient.
I run an A2W in my streetcar and there is nothing better, a reservoir would fit in the bed quite nicely.
The water just sitting in the A2W cooler is an incredibly efficient heat sink that I only turn the pump on from time to time.
Even ambient temp water works incredibly well, I haven't tried ice yet but I'm sure it will only help make more power.
If I know I'm going to be beating on it then I'll kick it on but even if its not running and I make a quick pull, my IAT's still stay very low, maybe 10-20 degrees above ambient tops.
I run a Frozen Boost Type 22 cooler, 3/4" lines, 2-3 gal reservoir and a Rule 2000 pump.
My cooler is located in the nose of the car so it's away from engine heat which I'm sure helps so you may want to consider having both the reservoir and cooler in the bed of the truck.
Water to Air Intercoolers
I have it on a manual switch and 90% of the time I don't even run it when driving around on the street.
The water just sitting in the A2W cooler is an incredibly efficient heat sink that I only turn the pump on from time to time.
Even ambient temp water works incredibly well, I haven't tried ice yet but I'm sure it will only help make more power.
If I know I'm going to be beating on it then I'll kick it on but even if its not running and I make a quick pull, my IAT's still stay very low, maybe 10-20 degrees above ambient tops.
I run a Frozen Boost Type 22 cooler, 3/4" lines, 2-3 gal reservoir and a Rule 2000 pump.
My cooler is located in the nose of the car so it's away from engine heat which I'm sure helps so you may want to consider having both the reservoir and cooler in the bed of the truck.
Water to Air Intercoolers
The water just sitting in the A2W cooler is an incredibly efficient heat sink that I only turn the pump on from time to time.
Even ambient temp water works incredibly well, I haven't tried ice yet but I'm sure it will only help make more power.
If I know I'm going to be beating on it then I'll kick it on but even if its not running and I make a quick pull, my IAT's still stay very low, maybe 10-20 degrees above ambient tops.
I run a Frozen Boost Type 22 cooler, 3/4" lines, 2-3 gal reservoir and a Rule 2000 pump.
My cooler is located in the nose of the car so it's away from engine heat which I'm sure helps so you may want to consider having both the reservoir and cooler in the bed of the truck.
Water to Air Intercoolers
Joined: Apr 2006
Posts: 3,891
Likes: 1,137
From: Grand Rapids, Michigan
You don't need low overlap with your cam. That's been proven not to be an issue on LS builds. Get a BTR Truck Norris cam with the aforementioned 78/75 w/ .96 A/R and it'll make more torque than you could want. It'll be out of steam by 5500-6000, but in a heavy 4X4 build, that's not detrimental. My 78/75 with a 1.25 A/R spools pretty quick with a 5.3 and I have a bigger cam (226/235@.050).
You don't need low overlap with your cam. That's been proven not to be an issue on LS builds. Get a BTR Truck Norris cam with the aforementioned 78/75 w/ .96 A/R and it'll make more torque than you could want. It'll be out of steam by 5500-6000, but in a heavy 4X4 build, that's not detrimental. My 78/75 with a 1.25 A/R spools pretty quick with a 5.3 and I have a bigger cam (226/235@.050).
Joined: Apr 2006
Posts: 3,891
Likes: 1,137
From: Grand Rapids, Michigan
There is nothing inherently good or bad about running a divided housing on an undivided outlet. Divided housings are good for spooling faster, but you have to build a special "firing order" based set of headers and it's generally not done on a V8 or V6, although it can be. Either will work, you're not likely to see a difference either way. A/R can be simplified if you think of it like pressure washer nozzle tips. Small ones create a lot of pressure but little flow, large ones are less pressure and greater flow. Smaller outlets (like the .96 A/R) will force the exhaust gases against the turbine with more force, spooling the turbo faster, but the small size creates a choke point for overall exhaust flow. For what you're doing, I think a good balance would be a .96 A/R with a cutout so the exhaust can dump almost immediately post turbine outlet. You can still have an exhaust Y'd in so it will be mostly quiet, but you can open the outlet for more power. My Firebird has a CO2 powered cutout that is controlled by my Holley ECM and opens progressively with a PWM controlled MAC valve. Best of both worlds. A full exhaust without a dump will severely choke your engine and keep overall power far below what you're looking for.
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Verdad Gallardo There is nothing inherently good or bad about running a divided housing on an undivided outlet. Divided housings are good for spooling faster, but you have to build a special "firing order" based set of headers and it's generally not done on a V8 or V6, although it can be. Either will work, you're not likely to see a difference either way. A/R can be simplified if you think of it like pressure washer nozzle tips. Small ones create a lot of pressure but little flow, large ones are less pressure and greater flow. Smaller outlets (like the .96 A/R) will force the exhaust gases against the turbine with more force, spooling the turbo faster, but the small size creates a choke point for overall exhaust flow. For what you're doing, I think a good balance would be a .96 A/R with a cutout so the exhaust can dump almost immediately post turbine outlet. You can still have an exhaust Y'd in so it will be mostly quiet, but you can open the outlet for more power. My Firebird has a CO2 powered cutout that is controlled by my Holley ECM and opens progressively with a PWM controlled MAC valve. Best of both worlds. A full exhaust without a dump will severely choke your engine and keep overall power far below what you're looking for.
I'm leaning towards a VS7875 divided 1.25ar with that summit manifold. Research says that will spool better than a 7875 open with .96ar and have less back pressure too. By the way I called BTR and they recommended their Stg2 turbo cam (220/223 .618/.618 113Lsa) over the truck norris for my scenario, so I ordered that.
Following your lead on the firing order, I did a bit more research into whether or not a divided housing is even worth it on an LS engine due to the firing order not being a perfect split between alternating left and right banks. Here's the answer I got: "The divided housing still reduces pulse interference enough to make a massive difference over an open housing"
Thanks for all the suggestions.
Last edited by Calypso; Apr 21, 2026 at 04:59 PM.
FWIW I just picked up a 6.0 yesterday (5.3 giving me head gasket issues due to .0015 out of flat deck and heads) and this will be going on my C3 which currently has the VS billet 70/70 turbo and a stage 1 High lift summit cam. The 70/70 has been my go to on my builds for street power. I have one in my 87 firebird as well. I run mine up to 6500 and the turbo has no problem getting up there and the boost comes in noticeably faster and harder that the 3 different versions of the billet 78/75 that I have. I’m also thinking of putting a cam in the 6.0 but also kinda don’t need it now that it’s boosted. (Originally was a cam NA 5.3). I was looking at the summit 218/228 stage 2 and run the LS6 springs. The stage 1 with 7lbs is too much for the tires already and I can’t push more than 450hp through the aluminum rear. With a 700r4 with a 2400 stall that’s like 500 at the motor. I’m stuck between leaving it stock and throwing in the stage 2 cam. That’s like a $400 cost for cam, springs and a timing set. Or I just leave it and hope the BP doesn’t decrease the boost as I have a lot of spring in the WG already. I think our goals are similar, for my I prioritize the low end 2000-5000
range as that’s where I spend 90% of the time. I don’t get to rev out to 6500 much as it means I’m being dumb and going to fast on public roads lol. I daily all my cars to work 40 miles in stop and go low speed traffic in blistering summer heat so I plan accordingly. If I need to rev out I can, is the turbo optimal for that no… but it is for 90% of my driving.
range as that’s where I spend 90% of the time. I don’t get to rev out to 6500 much as it means I’m being dumb and going to fast on public roads lol. I daily all my cars to work 40 miles in stop and go low speed traffic in blistering summer heat so I plan accordingly. If I need to rev out I can, is the turbo optimal for that no… but it is for 90% of my driving.
FWIW I just picked up a 6.0 yesterday (5.3 giving me head gasket issues due to .0015 out of flat deck and heads) and this will be going on my C3 which currently has the VS billet 70/70 turbo and a stage 1 High lift summit cam. The 70/70 has been my go to on my builds for street power. I have one in my 87 firebird as well. I run mine up to 6500 and the turbo has no problem getting up there and the boost comes in noticeably faster and harder that the 3 different versions of the billet 78/75 that I have. I’m also thinking of putting a cam in the 6.0 but also kinda don’t need it now that it’s boosted. (Originally was a cam NA 5.3). I was looking at the summit 218/228 stage 2 and run the LS6 springs. The stage 1 with 7lbs is too much for the tires already and I can’t push more than 450hp through the aluminum rear. With a 700r4 with a 2400 stall that’s like 500 at the motor. I’m stuck between leaving it stock and throwing in the stage 2 cam. That’s like a $400 cost for cam, springs and a timing set. Or I just leave it and hope the BP doesn’t decrease the boost as I have a lot of spring in the WG already. I think our goals are similar, for my I prioritize the low end 2000-5000
range as that’s where I spend 90% of the time. I don’t get to rev out to 6500 much as it means I’m being dumb and going to fast on public roads lol. I daily all my cars to work 40 miles in stop and go low speed traffic in blistering summer heat so I plan accordingly. If I need to rev out I can, is the turbo optimal for that no… but it is for 90% of my driving.
range as that’s where I spend 90% of the time. I don’t get to rev out to 6500 much as it means I’m being dumb and going to fast on public roads lol. I daily all my cars to work 40 miles in stop and go low speed traffic in blistering summer heat so I plan accordingly. If I need to rev out I can, is the turbo optimal for that no… but it is for 90% of my driving.
Ultimately I bought the nextgen 7875 with a 1.25ar divided housing. With a small 2" hotside and the divided housing, it should still spool fast enough and have a bit less backpressure. I'll report back once I get it all together and start driving it.
Thats exactly my sentiment. Who cares if it runs out of steam above 6500 when you're only running around town and want fast response. I called VS to discuss my goals and they recommended an 80mm 96/88 turbine 1.32ar t6, despite the fact I clearly stated I wanted low end torque and instant spool instead of top end. The guy still insisted a .96ar on the nextgen 7875 would choke a 370 so bad it wouldn't rev past 5000. I was shocked. That's completely opposite of what many people here say. There are several folks running 7875 w/.96ar and even racing them.
Ultimately I bought the nextgen 7875 with a 1.25ar divided housing. With a small 2" hotside and the divided housing, it should still spool fast enough and have a bit less backpressure. I'll report back once I get it all together and start driving it.
Ultimately I bought the nextgen 7875 with a 1.25ar divided housing. With a small 2" hotside and the divided housing, it should still spool fast enough and have a bit less backpressure. I'll report back once I get it all together and start driving it.
Just be careful about making too much boost down low, nobody wants bent rods lol.
TECH Enthusiast
Joined: Feb 2020
Posts: 734
Likes: 209
I agree and while a 75mm turbine in a .96 housing is definitely on the small side it will not be done at 5000 rpm , just need to look at what rel3rd was doing - lower 9s at 140+ @ 4000+ lbs and I think he was reving past 6500 . My 6L 7875 .96 cast pulls well to 6000 but did not go faster at all shifting at 6100 . Doesn't see under 5200 on a pass except going through 1st. I just switched up to the next gen with 1.25 , it was on sale in Dec so why not . No road or track time yet , winter won't quit