LS3 valvetrain questions
#1
Teching In
Thread Starter
iTrader: (1)
Join Date: Dec 2007
Posts: 23
Likes: 0
Received 0 Likes
on
0 Posts
LS3 valvetrain questions
I am building up an LS3 and wanted some feedback. I have 4.070 Mahle pistons and I am going to go with stock length H-beams from Callies with the stock crank. The cam is going to be from Comp cams. I picked up some SLP rockers setup for stock pushrod length. The engine is going to be a street engine and occasional autocross. I have stock LS3 lifters and pushrods. Should I upgrade these while I am at it? What makes LS7 lifters different? I know the camshaft may dictate pushrod length, so that decision will be based on the cam.
#3
Teching In
Thread Starter
iTrader: (1)
Join Date: Dec 2007
Posts: 23
Likes: 0
Received 0 Likes
on
0 Posts
They are 1.85 ratio and came with my heads. I was looking at the Comp 273 LR HR12. I will be replacing the patriot gold springs that came with the heads with the cam swap. Should I go back to stock rockers with a trunion upgrade? Are the SLP's junk or do they limit my cam options? Can I adjust for the ratio difference with pushrods?
#4
10 Second Club
iTrader: (1)
You wont need that big of a ratio with a cam since you'll probably already have a decent amount of lift. I would stick with stock 1.7 rocker arms. LS3 rocker arms are pretty stout. You may hear otherwise but Ive see them survive just fine for years on some pretty stout LS3 builds. I havent had any issues with mine with my TSP 231/236 .644/.615 cam. Ive had a Comp Cams rocker trunion upgrade set sitting around. Ive been to lazy to do the upgrade but at the same time the car has been running great. Just make sure your valvetrain is set up correctly, double check everything.
#6
Teching In
Thread Starter
iTrader: (1)
Join Date: Dec 2007
Posts: 23
Likes: 0
Received 0 Likes
on
0 Posts
I will probably stick with the stock lifters then. Valve spring change/pushrods were always in the plans with the cam change. I was hoping to get away with the SLP rockers but I didn't realize they would limit my cam choice so much. I guess I can try to sell them off and find some LS3's and do the trunion upgrade for peace of mind. The thinking on keeping the SLP's was the fact that they have upgraded trunions.
Trending Topics
#8
Teching In
Thread Starter
iTrader: (1)
Join Date: Dec 2007
Posts: 23
Likes: 0
Received 0 Likes
on
0 Posts
Since I have gotten some feedback. What do you guys think on the Comp for an off the shelf grind. I am looking for decent street manners. This one ranked fairly well in the GM High-tech LS3 cam article. I can't find a lot of info here on the boards. It is a 223/231 with a 112 LSA.
#10
12 Second Club
iTrader: (20)
Yes go back to stock rockers, sell the SLP's and get the trunion upgrade. There really isint much to gain and no you can't compensate by pr length, you gotta keep proper valvetrain geometry.
That Comp 273 LR HR12 is a cathedral port cam. Do you have cathedral port heads?
That Comp 273 LR HR12 is a cathedral port cam. Do you have cathedral port heads?
#12
10 Second Club
iTrader: (1)
I will probably stick with the stock lifters then. Valve spring change/pushrods were always in the plans with the cam change. I was hoping to get away with the SLP rockers but I didn't realize they would limit my cam choice so much. I guess I can try to sell them off and find some LS3's and do the trunion upgrade for peace of mind. The thinking on keeping the SLP's was the fact that they have upgraded trunions.