KingPin1094

iTrader: (12)

Alright so hears the deal. I bought an 02 camaro m6 with a blown LQ9, it broke a connecting rod. I have not taken it apart yet, but from what i can see through the hole in the oil pan is that the crankshaft is okay. Im looking to rebuild this motor and make close to 500whp. Im gonna use TFS 225cc heads, EPS custom grind cam (~240/~250), FAST intake/TB, 1 7/8" headers, 3" TD's, ect.

Ill definitely need to get pistons and connecting rods, but heres my question. Should i rebuild the bottom end and keep the stock displacement, or should i spend an extra $1000 to get a crank with a 4" stroke? How much extra hp/torque could i expect from 44 more cubic inches? My budget is not super tight, but i do not want to spend an extra $1000 to see little to no returns. Any opinions on this matter?

Tainted

iTrader: (9)

your gains will be pretty large and so will your tq gains. to me, its well worth the $1000

lemons12

iTrader: (71)

It will end up being over a grand FWIW..

I am using a power adder, therefore I opted to stick with a 370. The 1000+$ was better spent elsewhere on my short block/drive train than the little extra but in cubic inches.

You can hit 500Rw with a 370.. Especially in an M6.

george g

iTrader: (12)

If the connecting rod broke,you might be looking at some crank and block damage too.Broken metal slinging around in the cylinder isn't good.

KingPin1094

iTrader: (12)

You think so?

Well a 408 rotating assembly is ~$2,000. I thought a 4.030 bore is safe to use with a power adder? im not going to run one, but thats just what i thought. But do you think i can hit 500 with my setup? also what is a 370? bore/stroke?

If the crank is damaged im definitely going to be heading toward the 408 route, but i can rotate whats left of the connecting rod and that tells me the bearing isnt seized which is a good sign. i have high hopes that the iron block held together, maybe with some scoring in the cylinders. head is probably trashed thats why im going to get new ones.

Tainted

iTrader: (9)

A 370 is a 4.030 bore with stock stroke. Add the 4" stroker crank and you have the 408

I for sure think you will pick up some big gains

KingPin1094

iTrader: (12)

This car is also a DD, so i have to take account mpg a little bit. I wouldnt think it would be affected to much because of the double overdrive t-56 trans, but idk.

99LSS1

iTrader: (12)

There is a reason for the saying... There is no replacement for displacement!!!! The extra cubes will give you more HP and TQ without comprimising drivability. You will see a dropoff in MPG but that is expected for a bigger motor. Good luck with your decision.

Tainted

iTrader: (9)

Its not gonna be a huge difference. They dont do bad if you keep your foot off it.

KingPin1094

iTrader: (12)

yea ive been trying to talk to people that DD their 408, and theres not many of them. But they say highway driving is relatively the same, 6th gear going 60-80. Its only when your on it it will make a difference.

Tainted

iTrader: (9)

Fwiw im going to daily drive mine, and I put about 40-50k on my car per year. Ive got a big weight advantage though and my rear gears are 3.54 compared to most people running 3.73 & 4.10

KingPin1094

iTrader: (12)

Post Super Bowl bump for more ideas

thompson

iTrader: (4)

You will have no DD issues with either motor if built properly. You will not see gains in HP and little in Tq with the stroker assembly if all other components are the same. The short block is an air pump, If you blow through a Mcdonalds straw and can get x amount of air through getting someone who has larger lungs will not make any more air flow through it. You will simply put your motor into your power more quickly and play out at a lower RPM. If 500HP is all you are looking to make I would be looking into putting the $ somewhere else in the motor as the 370 with good pistons and rods will do that no problem. We sell them good to 800HP for $2959 and you will be able to DD and put you power adder on with no issues.

lemons12

iTrader: (71)

Yes you do!

Kyle... I'm sitting here tapping my block for my alternator hole... Is this something you guys offer to do for an added charge?
I don't mind doing it, I have the pilot hole done about to do my 5/16 bit then tap it. I just didn't know if you guys had the correct tools, I'm kinda limited in some areas to do it 100% "correct".

K Member will be here Wednesday... Everything will be ready to drop in the car and hopefully take it around the block this weekend!! Well maybe not burning tires.. But ya know.

RezinTexas

I drive my 383 iron block burb on the weekends, MPG's didn't change over the stock LQ4. highway cruising is the same, no real differences. If you build the motor properly and check ALL clearances/interferences, then check them all again - you will have no issues.

z28josh

I DD my 408 for the longest time no issues and driving from tx to nc I averaged 25 to 27 mpg on the highway that's with 4.10 gears. It's in traffic and the stop and go where the milage drops

KingPin1094

iTrader: (12)

Good explanation and analogy.

Thats impressive, especially with the 4.10 gears, which i was also planning on installing.

bww3588

iTrader: (49)

My opinion, if you're wanting 500 at the wheels and daily it, I'd opt for the 408. Larger cubes will always make more power more street friendly.

Example:

500 at the wheels in a 408 will have better street manners than the same power in a lesser cube engine.
Fuel mileage will be a toss up as the larger engine will have to work less to move the same amount of weight.

redtan

iTrader: (5)

I don't think a 25x/26x cam will be very DD and mpg friendly even in a 408. In a 364 it will be downright nasty to drive.

For a DD with not so much emphasis on mpgs, I would opt for the bigger cube/smaller cam combo just for the added torque throughout the powerband.

5mall5nail5

Honestly if it were me I'd build it out as large as I can. When you get tired of the 36x you will be wishing you went 408 or larger - with a power adder you can just add boost but on an NA setup you can't make it bigger after the fact.

Heck, I'd go 427 if it were me.