00fxd

Hey guys, I just took delivery [shipped across the country] of what I expected was a low mile '03 Lq9. Naturally when I inspected it I discovered it was an Lq4, I looked down the spark plug hole was able to determine that it contained dished pistons. It's going in my '65 Corvette with 3.36's and a 4speed. "Spirited driving". I was really looking forward to the lq9, maybe it's just the bragin' rights, but I'll be down a bit on power. Is there any way I could get the power back? Maybe a Ls6 cam? As it is a street car I do want to keep the truck torque which means retaining the truck intake and throttle body for now. Any suggestions or should I just run it as is?
Thanks, Frank

TierAngst

Wouldn't milling the heads or possibly running a thinner gasket bring your compression back up? I've always heard the only main difference is the compression between the two is that correct? Though naturally if you've got the motor out it would be a great time to do a cam swap which will put plenty of power into it for a mild setup.

SweetS10V8

iTrader: (4)

Try to get some money back...

00fxd

Thanks fellas. Sadly I don't think I will be recieving any money back but the seller has offered to help out in some way. We were looking at different ideas when the thought of an Ls6 cam swap came up.

00fxd

Milling the heads is a good idea, thanks. No one else has any thoughts? I see all sorts of answers to much more complicated questions here. I thought this grade one question would have more feed back.

IT_SS

iTrader: (5)

Stock 243 Heads and an LS6 cam should give you the power your looking for. The compression of the LQ4 is going to be a dog down low so the smaller combustion chamber of the 243 heads will give you a nice bump. Patriot has some bad a$$ heads 243 heads avail. You can sell the 317 heads to the (us) FI nutz.

Nimitz87

iTrader: (17)

only way to bump your compression would be to mill the heads and run a thinner gasket.

why do you want to use the truck intake though? get an ls6....

Chad

PREDATOR-Z

There are many ways to make it better with more power. All of which cost $$. How much are you willing to spend and what level performance are you looking at.

You should have gone for a LS2 swap.

To answer you LS6 cam Q: That is a 4K + cam, meaning power comes in late in rpms so it would not be the right choice.
But a custom cam with right valve events and overlap will liven it up even at 9.4:1 compression.

Nimitz87

iTrader: (17)

I'm running an lq4 bottom end w/ PRC LS3/L92 heads milled to 62cc chambers, 0.040 cometic gaskets and a SCR around 10.5:1 (little lower) and a DCR of 8.0:1

we'll see how it runs when it's together.

Chad

s346k

iTrader: (4)

compared to what? an lq9? i doubt you'd notice the .6 difference in compression. maybe 10rwtq? an lq engine with cathedral port heads and any stock ls manifold is going to make bookoo torque down low.

to the op: i would steer clear of the ls6 cam swap as mentioned. it is in fact a high(er) rpm cam and would definately take away from the low end grunt the lq4 has to offer. i would simply run the engine as if it were an lq9. i'm guessing that in stockish trim the differences would be hardly noticed, if at all. the truck intake has been proven to flow just as well as an ls6 in the higher rpm, yet still provide the low end tq needed to get a 7k lb pig moving. if you're really worried about the CR, throw a set of 243 heads on it and call it a day.

i would just throw the motor in and go. if it will be compared to any stock carbed sbc you will definately NOT be disappointed. even some modded gen 1 motors can't hold a candle to even a "low" compression lq4. the heads make all the difference in the world.

PREDATOR-Z

I would cam it with small duration tight LSA cam (some positive overlap). You'll get more below curve output with lopey grunt. I certainly would not want a cadillac smooth motor in such a beautiful 65. It needs to have some lope, not dragster but nice muscle thump.

This is what I would put in:

comp cam lobes:

220/226 .605,.600 110+2 LSA,

Power range 1600>6400 rpm, 3* positive overlap so nice melow thump, tons of trq below the curve.

If you are interested, PM me, I'll give you the specs to get it ground along with what springs, pushrods to run.

Mark

hammertime

iTrader: (1)

Mark gives excellent advice. I would take him up on that if it's in your budget.

Good luck!

00fxd

Thanks fellas sounds like good advise. .600 lift. wow. I'll pm you Predator. Looking foreword to the upgrade from the old TBI'd 400