LQ9 Cadillac engine upgrades?

[stricker76]

Have a LQ9 6.0L that i am planning to put into my 1975 Chevelle. Can anyone suggest some upgrades to this motor before i throw it in? Was thinking of a bbk intake, but everyone keeps telling me to go with a F.A.S.T. Really would rather aluminum, looks alot better. Was looking at some cams from texasspeed, but really have no idea how big to go. The car is basically just going to be a street cruiser. Would like to get around 400hp to the wheels. Any suggestions are appreciated.

[WS6]

You could always go with a carb style intake manifold or get an LS6 intake manifold. The factor plastic manifolds can take paint and powder coating so you can do it in silver or whatever color a powder coater can offer. I would highly advise against an aluminum intake unless it is the carb style.

As for power goals, you'll need headers for sure. A good all around cam for that engine would be a comp XER 228/232 on an 112 or 114 LSA. I love the 114 LSA personally. You could also go a little bigger and not hurt your low end power. I would not go bigger than a 232/236 though.

What rear gear ratio do you have and what trans are you going to use? You'll need a stall converter if you're going with an auto trans

[stricker76]

Guess i left out a few things. I have both 3.42 and 4.11 rear gears and havn't picked yet. Will have a 4L60E behind it. Want to stick with fuel injection. Don't like the look of plastic on the engine, which is why i wanted an aluminum intake.

[stricker76]

Oh, and the headers and a stall were figured on. I was surprised to see that hooker actually makes swap headers for an LS1 into my car.

[WS6]

I believe the chassis on a 75 chevelle is very similar if not the same as the 68-72 cars. Either way, hopefully those Hookers will work well for you.

If you're planning a 4 speed auto like a 4L60E, I'd sell both the 3.42s and 4.11s and get a 3.73. The weight of the car makes the 3.42s not so great for off the line acceleration. The 4.11s will be great off the line but totally kill your gas mileage and highway cruising. 3.73s will be a great compromise. Go with at least a 3200 stall again because of the weight of the car. A quality 3200 stall will drive fine around town and again be a good compromise.

Considering the torque that the engine can produce, I think you'll have a great driving car with this combo. You must keep your cam in check though. Most people want too large a cam in their engines. These engines can handle very large cams and still be "streetable" but their power band is actually very crappy for the street. A cam like I already mentioned should work very well for you. Keep the LSA on 114 or even 115 so that you can keep your torque up be keeping the cylinders pressurized. A 112 LSA will sound meaner because of the added overlap. That added overlap causes the cylinder pressure to bleed off. This is great for high rpm drag racing but it kills torque. You need torque in a car your size. The more the better and the broader the curve the better.

The BBK and Weiland aluminum intakes retain a lot of heat which is why I do not like them. Are you sure this doesn't look good enough for you?
http://thepowdercoater.com/gallery/d...?album=3&pos=9

An aluminum carb style manifold is actually the best choice for a intake on these engines. It delivers a more balanced air flow to all cylinders. There are a number of them out there and most of them allow the use of port fuel injection.

[ScotI]

An aluminum carb style manifold is actually the best choice for a intake on these engines. It delivers a more balanced air flow to all cylinders. There are a number of them out there and most of them allow the use of port fuel injection.

How much torque do the carb style intakes kill vs. a stock style (ls6) intake? I like the looks of the Edelbrock intakes & think one of those w/a 'carb' style TB would be a nice combo.

[WS6]

They don't kill any torque that's the beauty of them. They work better than the factory car manifolds.