MYTURBOT/A

Can anyone tell me the differance between the lq9 and lq4 heads. I know they lower the compression with a 72cc chamber. I know the lq9 flows alot like the ls6. Does it flow better then the lq4? if so hows the lq4 compared to the stock ls1 will i lose any performance going to the lq4 head on a FI motor? Sorry for all the questions but all the specs. show them to be basicly the same head but theres a big differance price wise. Thanks.

Jabroni

The LQ9 heads have the refined intake/exhaust ports like the LS6 heads do. They will offer a better flow rate than the LQ4 heads will. You stand to gain performance with either head because the lower compression ratio will allow you to dial more boost without as great a risk of detonation. If money is no object, go with the LQ9's for max gains. Personally, I'd go with the 2001 and up LQ4 heads. Compression ratio drop, better for F/I and cheaper than the LQ9's. 1999-2000 LQ4 heads (casting 873) are cast iron and not aluminum. Casting 317 are the aluminum ones. LQ9 heads are casting 035.

MYTURBOT/A

Thanks man, since the lq4 is alot less expensive I think i`ll go with them just want to make sure that they flow as good if not better then the stock ls1`s.

Jabroni

With some porting, they'll do fine IMO. Unported, the flow rates will probably be about the same but the CR will drop.

Whistler

iTrader: (46)

I'm not sure about the 317/035 heads and their differences.

I have a friend with an 03 EXT Escalade and it has 035 heads on it. Same guy also has an 03 H2 with 317 castings on it. These are both option code LQ9 engine.

I looked at a Silverado SS at the dealership last week, it had the 317 heads as well, and this is supposed to be an LQ9 here too. Also I posted a want ad on the board asking for a set of 035 LQ9 heads and a guy responded that his LQ9 in his 03 SS had the 317s as well.

??????

Does anybody have any concrete information on these heads and their applications and flow rates? Or Are we all referencing the GEN III head guide from GMHTP?

MYTURBOT/A

Does anyone know anyplace that i could call to get a positive answer? From what i`m getting it sounds like the lq9 is a low comp. ls6 head and the lq4 is a low comp ls1 head. I just dont want to bolt on a set of lq4s and have it kill my performance because they flow worst then the ls1s. Thanks guys.

BigTex

iTrader: (16)

The LQ9 and LQ4 head are the same. I have an 03 Silverado SS with the LQ9, but it has 317 heads. I have a take out motor from an 03 Escalade that we upgraded with a stroker adn it came with 317 heads. I've never seen an 035 head, and I look under every Escalade or SilvSS that I can find. My 317 heads are just like the LS6 heads with the D shaped exhaust ports. From what I've found out, there is no physical difference in the two heads. Both have a 71cc chamber and the D shaped exhaust ports.

FYI - The Denali and H2 vehicles have LQ4 motors, not LQ9s. The only LQ9 in production is the Escalade and the SilvSS, all other 6 liters are LQ4s.

Whistler

iTrader: (46)

T-t-t

Vents

iTrader: (9)

exactly what big tex said. i've had my hands on both sets, neither are any diffrent. both have big chambers, and both have intake ports SIMILAR to the LS6. not identical, but very similar.

FYI, i've been working with these core heads for a few years, and this isint magizine knowledge talking here, it's hands on experience. the LQ4 and the LQ9 heads are identical.

if you dont believe me, call up Terry @ patriot. he's got about 4000 cores 035 and 317 castings, and they're an identical casting.

it's the same deal as the 706's and 862 4.8 and 5.3L. both heads are identical, save a stamped number in the head.