bmk

iTrader: (2)

Greetings,

I have LQ4 with stock 317's & PSI springs, LS6 intake, ported TB, 226/234 .598 .578 110LSA 61º overlap, its in an old BMW so limited space currenlty only running 1 5/8 headers. I am looking for the best heads on a $1200 budget, this a street car so best fuel I can run is 91 so the compression can not be outrageous. Car is primarly a freeway car, I am pretty new to the LS engine so not really sure what would work best as far as size, chamber cc, valves etc.

Side notes:
On ocassion will be using a 100 shot via money maker set up, not sure if that changes much. Majority of the time will be ran N/A as N20 is not easy to come by and expensive down here

Long term the Car will be boosted but ill probably just keep the stock 317's for that unless you guys suggest using the 317's as a base for porting etc.

redtan

iTrader: (5)

Last sentence exactly. Send the current heads to be ported.

bmk

iTrader: (2)

Wouldn't a lot of material have to be removed to increase compression? Or material added to decrease chamber size

redtan

iTrader: (5)

Well depends on what compression you want. You can either mill them for more compression, or a place like Advanced Induction has a chamber welding process for 317s which will decrease chamber size also. Or both, I think you can get as low as 60cc with those two combined.

bmk

iTrader: (2)

High of compression as I can on 91. From everything I've read its usually better to start with another casting besides the 317's unless your going with boost. But again I'm no expert at all

redtan

iTrader: (5)

That's the case yes because they have big chambers, but with a company that can weld the chamber they are actually easier to get compression than say 243s.

A.R. Shale Targa

iTrader: (2)

http://www.competitionproducts.com/W.../#.VU2Aqmd0zIU
These are a pretty nice set of new CNC heads that you can just swap all your valves/springs/retainers/seals over to and with shipping, gaskets, and bolts still be at your 1200 budget......

bmk

iTrader: (2)

Those look pretty darn sweet. I'll have to look around for reviews on those

A.R. Shale Targa

iTrader: (2)

Call Wegner Automotive Research and speak to Carl himself as he often answers the phone over there in Markesan, WI
Extremely knowledgeable fella who used to do the LS engine program for the ASA stock car series.
He's also done a bunch of R & D for GM over the years.
There's a few more pics of them in my 368 MUTT thread in the gen IV internal

redtan

iTrader: (5)

How would one swap over OEM valves on a set of heads that have had a valve job done on them separately? Don't you have to basically "match" the valves to the valve job together?

A.R. Shale Targa

iTrader: (2)

yep....regrind the valves; lap them in to find where the valve job is located, then back cut the valves for added flow.
All 2" valves measure the same.

bmk

iTrader: (2)

This process sounds like would put me over my budget? or would I send out all of my componets so that he can assemble?

A.R. Shale Targa

iTrader: (2)

You can lap the valves in your self and just run em' but a shop should regrind them first for like 2-3 bucks each, not a huge expense. The only reason to back cut the intakes is for a few more cfm but it's not mandatory.

squalor

iTrader: (3)

Your 317 heads have the same 210cc intake and 75cc exhaust port design as the 243 heads everyone on here loves.
I'll tell you what I have planned for my 243 heads, as I'm on a strict budget. I plan to put a 30 degree back cut .030" wide on my intake valves only, exhaust valves stay stock. I plan to use my drill press and file like they do in this page:
http://www.diyporting.com/index.html
I plan to thin my intake valve guide boss a bit with my dremel and a 1/8 shank round nose tree aluminum cut carbide and leave the rest of the intake port stock. No port matching, no rocker boss removal, no shaping. On the exhaust port, I plan to thin and blend the valve guide boss. I plan to slightly widen the sides of the port with a file, .020 to .030 wider. I have a four dollar 50cc syringe I plan to use to measure port & chamber size after the work. I hope to just lap in my valves if the 45* is not porous. If it is not smooth, I will pay a local shop to cut them, a drill press is not accurate enough.
I won't flow the numbers that a cnc port would flow but the port velocity would be fast. Your stock intake port flows 257 cfm at .600 lift. Our LS6 intake starts to limit flow around 265 ~ 270 cfm so just a little de-shrouding around the valves in the chamber, the back cut intake, a thinned guide boss (without touching the valve guide itself) and a good valve job will get you past 270 cfm. I plan to use Livernois or TEA for the valve job. Read this thread: https://ls1tech.com/forums/generatio...hese-days.html
So less than $400 for a quality valve job and .010 clean-up mill could have your 317 performing well. For 91 octane, the limit is about 8.5 dynamic compression ratio. Don't think you have to go that high. It's not dynamic compression or static compression that matter, it's cylinder pressure. Cylinder filling that really matter.

bmk

iTrader: (2)

I have been browsing the parts classifieds and now really sure what CFM or chamber cc would be best for an Lq4

Any input on those?

Should I go with something that has the 4.0 bore or the will the 5.3 heads work

Rise of the Phoenix

iTrader: (27)

Another option is to scour the classified section for a set of used heads. Just be careful to make sure they are what the seller says they are.

Tuskyz28

Lloyd Elliott and call him. Do good work and is very honest plus he is affordable.

bmk

iTrader: (2)

Thats what im doing just not sure what to look for

Rise of the Phoenix

iTrader: (27)

AFR, TFS, PRC, MAST, etc. are good heads to look for. Sometimes you can find really good deals, or sellers willing to come way off their asking prices. Just make sure you get good pictures of the heads and ask lots of questions. Also make sure you research the sellers feedback.

whatsa347

iTrader: (6)

There's a set of prc 5.3's brand new for $1000 on the classifieds.