6.0 swap in Yukon XL, question about CR and cam
03-23-2009, 11:02 AM
#1
6.0 swap in Yukon XL, question about CR and cam
I was building a 6.0 for my HD that I just sold for my diesel. My wife has a 5.3 in her Yukon XL with 3.73s and a 4L60E it is a 2wd. The 6.0 I have 2 sets of pistons for. 1 being a set of LQ4 and the other LS2 pistons. I will run a set of Dart 225 heads I have that I can't seem to sale. They have a 62cc chamber. The cam I am going to run is HirdleJ's Vmax 218/224 114+2. My question is on the CR, should I run the LQ4 pistons to yeild a 10.9-1 cr or mill the heads for 11.1. Or I can run the LS2 pistons and be 11.3-1 I believe with stock MLS gaskets. I want the truck to have awesome low end and mid range, not a race truck but a strong DD that will have 0 issues. The stall will probably be a TB stall or something around 2400-2600. The tires are 31.6 inches thanks
03-23-2009, 11:38 AM
#2
If you were going to always run premium I'd shoot for the higher compression. With the LQ4 pistons you'd be able to sneak regular 87 in there with GOOD tuning. Either way you'd have excellent low end. Maybe for durability's sake and a woman driving you want the lower compression 
03-23-2009, 11:51 AM
#3
She always run Chevron 93 which is what we have available here in Alabama. We have 93.5 available but I prefer Chevron gas. The tuning will be handled by Vengeance since they flashed the computer once already for me. With it I have unlimited reflashes to correct changes made to the vehicle. I think the 11.3 cr would work out but I just want to be 100% sure before I pull the trigger
03-23-2009, 08:53 PM
#4
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A 218/224 cam in an 11.x:1 motor will make a brute low end motor with razor sharp throttle response, without a doubt. Be careful handing something like that over to an inexperienced driver, especially in a 2wd.
I would not touch the Dart heads and leave the chamber as large as possible. 10.x:1 is plenty for a 6.0L running 93 octane. On second thought, I wouldn't even use the Dart heads since the 218/224 cam does not tax even stock 317 heads much less 225cc Dart's. I'd keep trying to sell them and instead use something a little more timid and daily driver oriented. 317's milled down, 243's in stock-ish form or even better yet, ported 5.3L heads are my suggestion. I believe the Dart heads would put too much emphasis on the upper RPM band at a loss in low speed torque where the Yukon XL needs it most. The 5.3L heads would make for tire shredding torque down low and once re-worked by a competent machinist, would probably keep up with the LQ4's breathing demands until a reasonable ~6000 red line.
If it were my build, I'd use the LQ4 pistons and 5.3L heads first or as a second option use the LS2 pistons and 317 heads. When combined with that cam you mentioned, it would probably put down an honest 385-395hp and 420-430lb-ft of torque. What more could a wife ask for?
I would not touch the Dart heads and leave the chamber as large as possible. 10.x:1 is plenty for a 6.0L running 93 octane. On second thought, I wouldn't even use the Dart heads since the 218/224 cam does not tax even stock 317 heads much less 225cc Dart's. I'd keep trying to sell them and instead use something a little more timid and daily driver oriented. 317's milled down, 243's in stock-ish form or even better yet, ported 5.3L heads are my suggestion. I believe the Dart heads would put too much emphasis on the upper RPM band at a loss in low speed torque where the Yukon XL needs it most. The 5.3L heads would make for tire shredding torque down low and once re-worked by a competent machinist, would probably keep up with the LQ4's breathing demands until a reasonable ~6000 red line.
If it were my build, I'd use the LQ4 pistons and 5.3L heads first or as a second option use the LS2 pistons and 317 heads. When combined with that cam you mentioned, it would probably put down an honest 385-395hp and 420-430lb-ft of torque. What more could a wife ask for?
03-23-2009, 09:56 PM
#5
Well I have been trying to sale the Darts and haven't been able to. I refuse to give them away so instead I will just take them and toss them on the 6.0 I am going to put in the Yukon since I have them. I spoke with Pete at Vmax and he said that the Darts and that cam would be a home run but he suggested me to run the LQ4 pistons and mill the heads to get a 11.1 CR. I am really not to keen on that idea so I thinking I will just use the LS2 pistons and Dart heads for an 11.3-1 CR. If it makes close to 400 whp and 420 wtq plus was very driveable and got good gas mileage what more could husband of said wife ask for.
