brock4x

My heads and cam 80K mile 5.7 has a spun rod bearing that for some reason missed damaging anything else (lucky).

Let me know your thoughts on the following:

> Freshen up the 5.7 with rings and bearings along with new rod bolts

or

> Freshen high mileage LQ4 with the heads and cam from the 5.7.

Does the extra displacment make up the difference for the weight of the block? Apples for apples what kind of gains could I see?

I appreciate any advice... Thanks ahead of time!

Sales4@Texas-Speed

iTrader: (4)

I would recommend going with a iron 6.0 block. It won't make much more power in stock form, but the 6.0 block has a lot more potential. With a 6.0 block you can make a 408 stroker, which will definately offset the weight of the iron block. Those stroker motors make a lot more power and torque lower in the powerband than the stock stroke motors. Give us a call if you have more questions.

LS12Fast4U

iTrader: (1)

I agree with this guy ^

elias_799

iTrader: (8)

i would avoid that much weight of the iron block on the front end. if you want more displacement or the potential to make a bigger motor, get an ls2 block

LSX92Stepside

I would keep the 5.7. I have both, I would be more concerned about the weight in the car than the couple extra hp. The 5.7 has plenty of potential to make power. Just put a good set of heads on it. The 5.7 will handle better and get better mileage.

brock4x

The score is 2 and 2...

I guess I might go ahead and put the 5.7 back together and keep the 6.0 to build (maybe as a stroker) a little at a time. Plus it never hurts to have a back up bullet.

Thanks for the input!

Sales4@Texas-Speed

iTrader: (4)

If we are talking about an f-body and you don't road race you are not gonna feel the 70lbs up front. These cars are heavy as hell to start with...

krissoto

iTrader: (3)

+1 on the 6.0 block. Def way more potential.

elias_799

iTrader: (8)

that is not a proper excuse to adding weight to the car. 70 lbs is allot of weigh to add on a frond end of a car and you are going to feel it. the is a reason why gm installed an alloy block in the f body. it would of been much cheaper to cast the same block in iron then aluminum alloy

elias_799

iTrader: (8)

it is really not fair to compare a 5.7 ls1 to a 6.0 lq4/lq9 as far as potential

comparing an ls2 to a lq4/lq9 is a better match

Justus67

iTrader: (3)

Iron block, it will go any way you want for more power. Stroker motor, boost or a ton of spray. Its more cubes and considerably stronger. It's more weight up front, but if your building a DD or a street toy its not going to make that much difference. A road race car is a different story thats when the weight and suspension play a much bigger role.

Justus67

iTrader: (3)

How much is the iron block you are looking at, that will make a difference too.

Squirts11

iTrader: (14)

Wouldn't an aluminum ls2 block be considerably more expensive than a used iron short block?

Justus67

iTrader: (3)

You have to compare the LQ4/LQ9 to a 5.7 LS1 for their potiental, those are the options he has.

elias_799

iTrader: (8)

yes i would be more expensive because they are only found in gto's and corvettes, but if you look around you can find a good deal.

i think the ls2 motor is worth the extra money over the lq4/lq9 , if the op can afford it.

and the ls2 has just the same potential to make power as the iron block. one guy on this forum had his to 1700hp before it let go

elias_799

iTrader: (8)

it would be nice to know as to how much he wants to spend, maybe there are more options for him

brock4x

Sorry about the delay getting back to the thread.... My options include the original aluminum 5.7 that has a spun rod bearing or a high mileage LQ4 that I already have. Either engine will have to be freshened, so I consider that dollar for dollar. I will use my PRC 2.5 heads and Tsunami cam for which ever bullet I decide to build.

My question was whether or not it was worth it to carry the extra weight of the steel block to gain the extra cubes. I know the 6.0 has more "building" potential but stock bottom end for stock bottom end is what I have to base my decision off of. I have just about decided to go back with the 5.7 and keep the 6.0 to potentially build a stroker. Basically it has a better chance to get "bigger" out of the car than in it.

Thoughts?

rich5368

iTrader: (2)

If you're not boosting you'll need to either mill the head or replace the dished LQ4 pistons to get you're compression up. The LQ4 can take a lot of boost. There's no replacement for displacement. There is that 70 extra pounds. Really if you think about it 70 pounds isn't that huge of a difference. If I was a road racer I'd stay as light as I could up fron for balance, but as a straight line racer I'm fine with the extra 70 to get the cubes and more power. That and I can't afford an LS2 block.

Justus67

iTrader: (3)

^^^^ Well put.

elias_799

iTrader: (8)

don't want to be a jerk, but it is cast iron.

anyway, go over everything that has been said here and make your own decision

good luck