Stampede4ever

I have came across a LQ4 with 317 heads, and was wondering should I just keep those or find a set of affordable 799 heads? I've read the the 317 flows close to the 799, but has a bigger CC. Or buy a set of use L92 Heads? Looking at building a mid street car/daily driver.

Thanks.

JakeFusion

iTrader: (7)

317 are the same as the 243/799 head but with a larger combustion chamber as you have noted.

So it flows fine. But for a street car, I'd want to bump the compression. If you are running boost... the 317 untouched would be a good head. L92/LS3 heads stock would be an upgrade for an FI motor. But NA, I'd just keep the 317s and get them ported and possibly welded up. Advanced Induction does combustion chamber welding. So you could get it at 60cc or something without losing piston to valve clearance.

z-maro

iTrader: (18)

Like Jake said the chambers can be welded up to bump compression. I am using a set of 317's on my build that Advanced Induction ran their 232cc CNC program on, and welded up the chambers to 62cc. They actually may flow slightly more than a 243/799 head with the same CNC program that were milled to 62cc because I believe milling heads negatively affects the flow.

Hotrodhoop

Ls7colorado

iTrader: (3)

448rwhp with stock truck intake and stock exhaust manifolds??? Wow,
what does minus short tube headers mean?

Hotrodhoop

Ls7colorado

iTrader: (3)

Ahhhhh gotcha, nice numbers, and great torque! to peak at 5500 though im sure its getting choked

omc8

iTrader: (7)

Having Ai weld up the chambers is a great option , I like to know if they will do the chamber work A la carte or have to be done with other services minimum rebuild or cnc work .

Utinator

I just bought a set of 317 heads for my stock LS1. I was going to have the heads milled and ported, but I don't know what to tell the guy doing the work. He was asking about chamber size (what cc). I have no idea. I know the 317 are lower compression, so I want to increase that. I thought milling the heads would increase the compression, so why would you weld them? Does anyone know what the compression ratio is on stock LS1s?

00pooterSS

iTrader: (40)

To increase compression you make the chamber smaller, you do that through milling or welding in material to take up space. Welding in material allows for more valve drop (more distance between the piston and valve).

To know how much to mill you need to know what compression ratio you want.

Utinator

I was hoping someone could tell me what compression ratio I want. I just read several threads about heads, cams, valve springs, and intake manifold CFM. Anyway, I found a thread that said the stock LS1 has 66.67 cc for 10.1 compression. I'm guessing I need to stay close to that in order to keep the car running well. I'm planning a cam swap at the same time, so I'll probably just start a new thread. I really just need to know how to make these heads work with everything else I already have.

I know the heads have to be milled due to a rough spot caused when the head gasket blew. I'm guessing about .010" would be enough to "clean" the mating surface. of the head. I'm not sure how much that would change the compression.

G Atsma

What kind of gas are you going to use? 91, 93, E85?

Utinator

I'm starting a new thread. I don't want to de-rail this one.

G Atsma

Cool! Good idea!

wannafbody

iTrader: (2)

Maybe you could sell/trade 317 heads to someone who's going forced induction and get a set of 243s.

ss.slp.ls1

iTrader: (36)

If you have the budget for LS3/L92 heads and intake I would go that route. It really depends on your budget and horsepower goals.

Stampede4ever

Well, I bought a set of 799 heads, and those are the ones will be using for now with an ls1 intake on a LQ4, but I do have good set of 317s. What is the average price to have them welded up, and ported? And I think I have a set of 823s, I have to look again tomorrow. Looking at the next motor, would really like to get a 6.2 block, this is coming from an old 5.0L guy, and I really liked the smaller cubic motors, but with the ls, I want big as I can, or just add boost.

Stampede.

rednari2

iTrader: (1)

Here's a suggestion. You could use thinner HGs, if the pistons are flush or slightly out of the deck. This will also give you two things: 1) The quench distance will tighten thereby increasing the squish; and 2) the larger chamber has more A/F volume. PVC should not be a problem because of the larger chamber and the increased squish makes more power and acts like octane to resist detonation. Besides you already own the heads so port them and cut the EXH throats.

Tuskyz28

A really simple powerful combo but still affordable.
Basic 6.0 shortblock
TFS 228/232 cam
LS3 intake
LS3 heads
long tune headers

Car craft just built this exact build this month and made 515 horses at the crank.

fakky

Never heard of this.
What kind of costs ?