862s + LQ4= cam
08-14-2020, 02:27 AM
#1
On The Tree
Thread Starter
862s + LQ4= cam So I just picked up a good LQ4 shortblock for $300. My ‘C4 currently has an lm7 with ss2 cam that needs to come out to change the rear cover. Don’t see much point in dropping it back in since I’ve got this 6.0 now. Ive read mixed things on the 862s on a 6.0.
Any input on this set up plus cam recommendations?
Any input on this set up plus cam recommendations?
08-14-2020, 05:01 PM
#4
I'm guessing you're just gonna move the existing 862s from the LM7 to the LQ4?
It's going to have higher compression than the LQ4 did originally, but somewhat limited flow due to the smaller valve and all that. Probably not enough to really "hurt" but enough that a "shoot for the moon" choice would fall flat.
I'd think about any of the same cams that work well in stock LS1s with unported stock heads would work well in that combo, especially the ones on the smaller side (to where they don't force the engine to have to rev way up to make its power). Something in the 224°/228° sort of neighborhood. Details would vary depending on transmission, converter if any, and gears.
It's going to have higher compression than the LQ4 did originally, but somewhat limited flow due to the smaller valve and all that. Probably not enough to really "hurt" but enough that a "shoot for the moon" choice would fall flat.
I'd think about any of the same cams that work well in stock LS1s with unported stock heads would work well in that combo, especially the ones on the smaller side (to where they don't force the engine to have to rev way up to make its power). Something in the 224°/228° sort of neighborhood. Details would vary depending on transmission, converter if any, and gears.
Last edited by RB04Av; 08-14-2020 at 07:11 PM.
08-14-2020, 05:50 PM
#5
862/706 make more power than 243's and quite a bit more than 317's stock for stock on cam only engines. The compression increase seems to more than make up for the SLIGHTLY less flow they have.
I have ran both and when I switch from 706 to 243's I couldn't tell a difference on my cam only 6.0
I have ran both and when I switch from 706 to 243's I couldn't tell a difference on my cam only 6.0
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G Atsma (08-14-2020)
08-14-2020, 11:10 PM
#7
But the 823/821 heads have good midrange and excellent topend.
The biggest advantage is also being able to run a LS3 intake, witch is comparable to the high end aftermarket cathedral port intakes.
You can purchase an entire LS3 topend for what one of high end cathedral port intakes cost.
Or if you can fit it under your hood and your not concerned with looks you can save even more money and get the rectangle port truck topend witch will make the same power.
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08-14-2020, 11:45 PM
#8
TECH Enthusiast
The ss2 is a good n/a camshaft and it's more suited for the 6 liter than the smaller LM7. If the lobes are still good and you bump up to the recommended 10.5+ compression for the ss2, I'd spend camshaft money elsewhere. I ran the ss2 in a LQ9 and was happy with it. I swapped it out for a Cam Motion little chopper for a little more bottom end torque. Upgraded the 317's to a set of PRC 225 heads that raised my compression to 11.4 and with the Cam Motions early intake valve closing at 33* the calculated dynamic compression was just to high... hence the third cam. Wish I'd never sold that ss2 and used the cam(s) money elsewhere myself.
08-16-2020, 09:37 AM
#9
TECH Fanatic
Here's mine. I put it together myself with all used parts except for the pistons and rings as I had to have the block bored 0.065" over because it was damaged. I used LS3 style flat top pistons. I originally put it together with 853 heads and it ran very well however I had a leaky head gasket because I popped a radiator hose and overheated it (I'm very hard on my stuff I use this one to deliver pizza 4 days a week) and so I switched out the 853 heads for a set of 706 that I had from my old 4.8 l I am very glad that I did, This car still has the stock torque converter and 2.73 gears The 706 heads maximize the torque production in the stock power band area and are a perfect match for the rest of this setup with my little 212-218-115 LSA cam I couldn't be happier with it
08-16-2020, 04:16 PM
#10
On The Tree
Thread Starter
I would recommend going to flat top pistons if you do and your staying N/A, otherwise you still will be around 9.6:1 compression, flat tops will bump that up to around 10.4:1
But the 823/821 heads have good midrange and excellent topend.
The biggest advantage is also being able to run a LS3 intake, witch is comparable to the high end aftermarket cathedral port intakes.
You can purchase an entire LS3 topend for what one of high end cathedral port intakes cost.
Or if you can fit it under your hood and your not concerned with looks you can save even more money and get the rectangle port truck topend witch will make the same power.
But the 823/821 heads have good midrange and excellent topend.
The biggest advantage is also being able to run a LS3 intake, witch is comparable to the high end aftermarket cathedral port intakes.
You can purchase an entire LS3 topend for what one of high end cathedral port intakes cost.
Or if you can fit it under your hood and your not concerned with looks you can save even more money and get the rectangle port truck topend witch will make the same power.
08-16-2020, 04:17 PM
#11
On The Tree
Thread Starter
I would recommend going to flat top pistons if you do and your staying N/A, otherwise you still will be around 9.6:1 compression, flat tops will bump that up to around 10.4:1
But the 823/821 heads have good midrange and excellent topend.
The biggest advantage is also being able to run a LS3 intake, witch is comparable to the high end aftermarket cathedral port intakes.
You can purchase an entire LS3 topend for what one of high end cathedral port intakes cost.
Or if you can fit it under your hood and your not concerned with looks you can save even more money and get the rectangle port truck topend witch will make the same power.
But the 823/821 heads have good midrange and excellent topend.
The biggest advantage is also being able to run a LS3 intake, witch is comparable to the high end aftermarket cathedral port intakes.
You can purchase an entire LS3 topend for what one of high end cathedral port intakes cost.
Or if you can fit it under your hood and your not concerned with looks you can save even more money and get the rectangle port truck topend witch will make the same power.
08-17-2020, 06:56 AM
#12
All the flat top factory 6.0 pistons are gen 4 rods.
Several have done with without balancing and not had problems, myself included.