Hey guys im at a cross roads with my LQ9 build. I have the guy at my machine shop adding up some prices for some parts so in the mean time i thought id ask and see what you guys though about what direction i should go. Im going with new rods and pistons regardless of what direction i go. Due to a budget im going to try and go with A or B instead of both. My goal is to make 450-500 horse.

A) Buy the entire rotating assembly with a stroker crank to make my engine a 408. Stick with the stock cast 317 heads with a small porting job.

B) Take the money i would have spent on the new crank and buy a set of L92 heads, go with my stock crank. The guy at the machine shop is trying to shy me away from the L92's to stick with the 317's, he says it will make my engine more street-able and give me more low end torque. Im just going to be ripping around town and not on the strip so this might make sense.

What do you guys think?

 

What is your budget exactly?

 

Im trying to build the thing for about 6K. My problem right now is the Canadian dollar is so poor the exchange rate is killing me when i buy my parts from the states. Costing me like 40%. I have to buy pistons, rods, a Fast intake with throttle body, injectors and fuel rails and a wiring harness. So regardless if i can save 1000$ on either heads or a crank i figure it will help with the exchange rate.

 

Why tear into the motor?
Sofar you are giving yourself poor options.
Blindly chasing cubes, blindly chasing flow bench numbers. You are begging to spend too much on mediocre results.
I would leave the shortblock alone and find some 243/799 heads with some porting and FAST. Cheaper than a stroker, way better response than the LS3.
The LS6 makes more power per cube than a LS3......

 

LS horsepower is in the valve train, not displacement

 

Go with the 408. If you're building an engine, it's really not much more to upgrade to a forged stroker crank. You shouldn't have any problem hitting your goals with 317 heads and mild port work. You will certainly make more overall power with the additional cubic inches.

 

And the debate ensues. Here's the deal. With 6K, you can do a well optimized top end and get in the upper 400's and reach your power goal. But you won't get it throwing parts at it. Think of the motor as a Rubik's cube. You can't change the blue face without changing the rest of the cube. Your heads and cam and intake need to work together. Compliment each other's strengths and compensate for each other's weaknesses. your valve train needs to be in good control. Not floating or lofting your valves, no pushrod flex, and good strong lifters. To get 500 with stock cubes, plan to rev past 7K, and build your top end accordingly.

There are builds on here where people build a 408 and get very underwhelming numbers, but with supremely flat torque curves, they are probably a blast to drive. But then you can go back in later with a top end optimized for your 408 and hit 550.

However for 6K, you won't get to do a great top end and a 408. If you plan to go back in later, it's easier to put a good top end onto a 408 than it is to put a 408 under a good top end.

Third option, for 6K, you could put one of those snail-looking things on to force feed your motor and get 500.

Or you could do a relatively budget build and then spray with laughing gas to get the extra 100-hp when you need it.

 

People are way too quick to want to spend money on the shortblock. It is the worst return on your dollar.

Now it is a fair point that topend can be swapped later if you do a shortblock now, but IMO people jump on the shortblock bandwagon without considering a LQ9 with good heads (ported 243s)and cam should be rollbar territory in just about any car, even old body on frame "big" cars from the 60s to 90s.

 

Im ripping the engine apart because it has 200,000K on it and im doing the rebuild for fun... Maybe im chasing this and that blindly but as i understand the rods are a weak point and i need new pistons anyways so maybe just buying an entire new rotating assembly with a stroker crank might be the way to go for me.

Haha alot of guys tell me the power is in the top end but i need to replace half my bottom end anyhow...

I wasn't planning on turbos or spray... The guy at my machine shop tells me up and down to build the thing for torque and not worry too much about loosing out at the top end. Im building the engine for a lowered 1975 chev pick up step side thats just built for the street. No stal or anything like that just something that will be a blast to drive!

 

In that case, build the 408, since you're in there anyways. Send the 317's for porting. Go for about 11:1 compression, cam duration in the mid 230's. Nice light valves, 11/32 pushrods, TBSS intake, LS3 injectors, and go have fun.

You'll probably break your budget a little bit, but not too bad. A 408 will make torque, so don't worry about trade offs.

 

It stems from the singly minded "no replacement for displacement" crowd. Like all cliches, the phrase should have been axed the first time it was stated. Yes, there was a time when poor head/valve train design & heavy cars made increasing displacement one of the best available options for improvement, but, even then guys new that headers & a cam would wake her up.

Today, a H/C LS1 w/ a stable valvetrain can out power the larger displacement STOCK LS7 (not in TQ, but, in overall HP). TQ is the major advantage of displacement NA. Yes, it's a key component of HP, but, so is RPM. Hmmm, maybe we should coin another cliche; "airflow makes her go," "there's no flow without dough" or "put some thump in your pump." lol, lol... Each equally as lame as "no replacement for displacement."

There are dozens of ways to replace displacement.