5.3 LS Motor
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On The Tree
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From: Canada NL
5.3 LS Motor Hey i have a 5.3 motor that was given to me it had the 706 heads but i dumped them, seeing that they like to crack. Question is the 319 heads what are they like?. Thinking about going with them plan was to go with a cam, those heads, and a LS6 intake or Fast 92 haven't made up my mind on that yet. The block is cast iron, how much spray do you think a stock bottom end will handle? I always wanted to build a motor, and spray it. I was thinking a 150 to 175 shot, i see videos with guys running turbos on stock 5.3's with no problems. If they can handle turbos spray should be good. What is the best cam to go with? so many choices out there.
Never heard of 319 heads, but you should pick up some 243s for more compression. 150 shot should be ok for a while given you have the right tune and fueling.
As far as cam, talk to a cam vendor about spec'n you a cam specifically for the setup you are running.
As far as cam, talk to a cam vendor about spec'n you a cam specifically for the setup you are running.
Some of the specifically Castech manufactured 706s had issues but to blindly pitch them without understanding if they were even made by the company with some failures is pretty stupid.
As said 317s have a big chamber, they flow well but would be a bad choice for a NA 5.3l.
As said 317s have a big chamber, they flow well but would be a bad choice for a NA 5.3l.
Some of the specifically Castech manufactured 706s had issues but to blindly pitch them without understanding if they were even made by the company with some failures is pretty stupid.
As said 317s have a big chamber, they flow well but would be a bad choice for a NA 5.3l.
As said 317s have a big chamber, they flow well but would be a bad choice for a NA 5.3l.
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On The Tree
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From: Canada NL
Sorry they are the 317's the 706's are already gone and yeah they were cracked. I am thinking about going with a set of AFR's also to be honest, i am taking my time with this build and i want to do it right the first time. Trickflows are another head i am looking at decisions decisions..
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People are too quick to jump on the aftermarket head bandwagon.
If looking at spray I would save some money by using a ported OEM cathedral head LS6 intake and use the savings to setup the nitrous very well with all the proper safeties.
You get into aftermarket heads you need to look at swapping them to PM guides or going to a heavy harder to control aftermarket rocker, the costs spiral out of control pretty quickly.
People are too quick to jump on the aftermarket head bandwagon.
If looking at spray I would save some money by using a ported OEM cathedral head LS6 intake and use the savings to setup the nitrous very well with all the proper safeties.
You get into aftermarket heads you need to look at swapping them to PM guides or going to a heavy harder to control aftermarket rocker, the costs spiral out of control pretty quickly.
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On The Tree
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From: Canada NL
Like everybody i am trying to do this on a budget seeing that i have 2 other vehicles. I can get the 317's for a good price i am told they can just bolt up and go, but i will get them checked out. I am planning on going with a LS6 intake i am going to port the heads, get a cam that matches what i want. Like everyone i think i will be looking for a foxbody Mustang, or S10 truck but i am leaning towards the foxbody. At first i was going to convert frm LTX to LSX, but where i live, i would be better and cheaper to buy a LS Camaro. So i think i will purchase the 317's and start off with the build. Another question is Texas Speed a good place to buy a cam or go with Comp Cams, or Eldebrock? Which is the best place to shop?
862s should be the same price..$150 or less for a nice set. You already don't have a lot of compression with an early 5.3 like yours. 9.5:1. When you go lower, it wont be fun. Good LSx OEM heads are a dime a dozen so don't buy the wrong thing just because you think someone I giving you a deal. I have a set of LS1 heads that were taken off at 12K miles and they are beautiful and probably only worth a bit over $100.
BTW, 862 is the factory head on a lot of earlier 5.3s. 706 is the same basic head but of course had the problems. 862 did not have these problems and is the actual direct bolt on replacement for a 706. 317 will bolt on but is different. And you can mill the 862 and get compression up in the 10+ range for even more fun.
BTW, 862 is the factory head on a lot of earlier 5.3s. 706 is the same basic head but of course had the problems. 862 did not have these problems and is the actual direct bolt on replacement for a 706. 317 will bolt on but is different. And you can mill the 862 and get compression up in the 10+ range for even more fun.
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862s run between $100-$150. I would go with 862s and, if money allows, have the heads milled a little bit to bump up the compression.
Or you can run 862s and get some flattop pistons and be at around 10.5:1.
Or you can run 862s and get some flattop pistons and be at around 10.5:1.
Thread Starter
On The Tree
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From: Canada NL
I am going to hold off and see if i can score a set of 243's if i can't i will go with the 862's. I was researching the 317's, they are awesome for turbo's or blowers but i am not going that route. I want to build a car the way i want.
Agree on 243 = good heads. Don't they have a slightly larger chamber than the 862? Mill a bit to get compression up? Or is the ~3cc not worth worrying about? What do you guys think? I had this same question when I was building my last 5.3.
I've since jumped on the aftermarket head bandwagon though, but that's for my Mustang.
The ones I have didn't need a valve job at all. They could have been run as is, but I wanted a better valve job to go with the bowl work I'm doing. When you buy used, obviously you run the risk of really getting something that's in good shape, or will need some work. Those "like new" heads for $550 could have a broken guide and a bent valve, but you wouldn't know until you take them apart.