6.0 cam choice
09-07-2021, 08:31 PM
#1
6.0 cam choice
Having a hard time picking a cam out.
Rcsb truck 3.73 gears, 6.0 with gapped rings, 3000 stall, upgraded springs and rocker trunion kit, 706 heads, and truck manifold. 55lb injectors. Looking at the btr ls1/ls6 stage 2 or stage 3 cam.
truck has long tube headers with 3” offroad y pipe and cai.
Any other cams to look at?
Rcsb truck 3.73 gears, 6.0 with gapped rings, 3000 stall, upgraded springs and rocker trunion kit, 706 heads, and truck manifold. 55lb injectors. Looking at the btr ls1/ls6 stage 2 or stage 3 cam.
truck has long tube headers with 3” offroad y pipe and cai.
Any other cams to look at?
09-07-2021, 11:02 PM
#2
with gapped rings
What gap?
For a TRUCK I would NOT go with a LS1/LS6 cam, ANY stage. I'd go with a TRUCK cam. Probably a "Stage 3" one; any number of cam grinders will supply one that's around 216 - 218° intake, 6 - 8° more exhaust, .550" or so if you're not willing to carefully optimize the springs and the rest of the valve train AFTER building but instead would just like to buy something and slap it together and run it, up to .600" if you are more adventurous and meticulous and detail-oriented and you have the right tools.
For a near stock TRUCK motor as you describe, in a TRUCK, I'd stick with TRUCK cams. Something designed to not give up too much low-end torque, while extending the upper RPM range as much as possible. NOT a car "performance" cam no matter what. Even though it will fit and "work" fine. It won't be right for a TRUCK.
09-08-2021, 09:28 AM
#4
.028" is kind of ALOT of ring gap. Not that it's likely to be a problem or anything like that; just, it's ALOT. Like, set up for 300 HP of nitrous, or some such.
The worst thing you can ever have with ring gap is, too little. I'd rather have too much than too little. Maybe not that much too much, but at least a little too much.
"Rule of thumb" for the top ring on typical pistons (the heat conductivity of those affects how hot the rings get and therefore how much much they "grow" when running) is something in the range of .0045" of gap per inch of bore diameter, and an additional .0005" - .001" per inch for heavy abuse; which would put a "normal" build in the .018" - .022" type of range. Then most people feel that the 2nd ring should be slightly more open than that, maybe another .001" per bore inch. So a typical "hot street" with a bit of track time might get something like .020" on the top and .023" on the 2nd.
But that's all irrelevant to the cam selection. The best match of cam to application still looks like a truck cam in the 216, 218, maybe at the most 220° neighborhood. High .500"s to .600" of lift. Not a car cam, since the load on the motor will be so much greater.
The worst thing you can ever have with ring gap is, too little. I'd rather have too much than too little. Maybe not that much too much, but at least a little too much.
"Rule of thumb" for the top ring on typical pistons (the heat conductivity of those affects how hot the rings get and therefore how much much they "grow" when running) is something in the range of .0045" of gap per inch of bore diameter, and an additional .0005" - .001" per inch for heavy abuse; which would put a "normal" build in the .018" - .022" type of range. Then most people feel that the 2nd ring should be slightly more open than that, maybe another .001" per bore inch. So a typical "hot street" with a bit of track time might get something like .020" on the top and .023" on the 2nd.
But that's all irrelevant to the cam selection. The best match of cam to application still looks like a truck cam in the 216, 218, maybe at the most 220° neighborhood. High .500"s to .600" of lift. Not a car cam, since the load on the motor will be so much greater.
09-08-2021, 06:02 PM
#5
in before 212/218 
i'd say something along the lines of a 220/220 or a 219/224 with mid-500s lift. LSA between 112-116 depending on how wide you want the power band (lower will be lopier & more 'fun' for emissions tuning).
but honestly, talk to the dudes at Brian Tooley, Texas Speed, or the like - they're the ones who're paid to give you a good recommendation based on how you use the truck.
i'd say something along the lines of a 220/220 or a 219/224 with mid-500s lift. LSA between 112-116 depending on how wide you want the power band (lower will be lopier & more 'fun' for emissions tuning).
but honestly, talk to the dudes at Brian Tooley, Texas Speed, or the like - they're the ones who're paid to give you a good recommendation based on how you use the truck.
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dantheman1540 (09-08-2021)
09-09-2021, 08:09 AM
#6
TECH Veteran
Don't disrespect the basics son!
09-09-2021, 09:21 AM
#9
TECH Veteran
