LM7 block vs. LS1 block
#1
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LM7 block vs. LS1 block
When building a 383 stroker, Which block would be better? I am assuming everyone will say the LS1 block but is it really worth the extra money? As far as I know LM7 ENGINES can be had for 500-800 dollars complete. Not so much for the LS1. Sooo.. which one is better? Pros and cons of each one?
Ps. I don't really care about everyone wanting to throw in "build a 408" or "ls2 block". It's been said so please stick to the question at hand. Thanks!
-Michael
Ps. I don't really care about everyone wanting to throw in "build a 408" or "ls2 block". It's been said so please stick to the question at hand. Thanks!
-Michael
#2
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If you don't mind the extra 100 pounds go with the the LM7 VS the ls1. You will also have to factor in the extra cost to bore out the the lm7 to 3.905" VS honing out the ls1 to 3.905.
Also what are your goals ? Power, N/A, Forced induction ect ?
Also what are your goals ? Power, N/A, Forced induction ect ?
Last edited by conan; 09-06-2012 at 09:05 PM.
#4
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Skip the aluminum. The extra 100 lbs of the iron block can be made up elsewhere.
The added cost of boring the iron block versus the honing of the ls1 is offset to some people by convenience. SImply because the ls1 block can only handle a .007 overbore max. If you get it to the machine shop and the cylinders don't clean up with .007 removed, your block is basically junk and your looking for another. As long as the iron block isn't cracked, your fine.
The added cost of boring the iron block versus the honing of the ls1 is offset to some people by convenience. SImply because the ls1 block can only handle a .007 overbore max. If you get it to the machine shop and the cylinders don't clean up with .007 removed, your block is basically junk and your looking for another. As long as the iron block isn't cracked, your fine.
#7
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Weight really isn't a factor because it is not a designated race car, just a fun street car. And my goals for this are to eventually add nitrous but only 150 shot or so. Nothing too extravagant. I was leaning more towards the LM7 because I think they have a pretty cheap price tag compared to the LS1.
My next problem is that I'd like to see this car at 500 hp N/A. I am still reading builds and researching them and from what I've read it isn't all that difficult. What are your guys' thoughts on this? What are some common builds? I was thinking a rotating assembly from TSP would do the trick... Thoughts?
Good info so far guys. Thanks!!
-Michael
My next problem is that I'd like to see this car at 500 hp N/A. I am still reading builds and researching them and from what I've read it isn't all that difficult. What are your guys' thoughts on this? What are some common builds? I was thinking a rotating assembly from TSP would do the trick... Thoughts?
Good info so far guys. Thanks!!
-Michael
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#8
I hate to say it, but what about picking up a 6.0 iron block and leaving the stock stroke so you get a 4.00" bore...that opens up a huge selection of head options that aren't there for the 3.90" bore.
Like said, just throwing that option out there.
But, between your two choices up top is go for the lm7 block over the ls1 block if your starting out without any motor.
Just curious, what car is the motor going in? There are lots of ways to offset the added weight of the iron block
Like said, just throwing that option out there.
But, between your two choices up top is go for the lm7 block over the ls1 block if your starting out without any motor.
Just curious, what car is the motor going in? There are lots of ways to offset the added weight of the iron block
#9
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500 at the crank is not all that difficult on ls1 cubes, at the wheels is a different story.
If your after 500 at the wheels, and you don't have anything to start with, I would look for a 6.0 block.
The added cost of the boring of the 5.3 will be offset by the added cost of the iron 6.0. Rotating assembleys are the same price as well. In the boat your in, you can build a 408 for the same price as an iron 383 and hit your power goals easier and it will be more driveable on the street.
If your after 500 at the wheels, and you don't have anything to start with, I would look for a 6.0 block.
The added cost of the boring of the 5.3 will be offset by the added cost of the iron 6.0. Rotating assembleys are the same price as well. In the boat your in, you can build a 408 for the same price as an iron 383 and hit your power goals easier and it will be more driveable on the street.
#10
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I hate to say it, but what about picking up a 6.0 iron block and leaving the stock stroke so you get a 4.00" bore...that opens up a huge selection of head options that aren't there for the 3.90" bore.
Like said, just throwing that option out there.
But, between your two choices up top is go for the lm7 block over the ls1 block if your starting out without any motor.
Just curious, what car is the motor going in? There are lots of ways to offset the added weight of the iron block
Like said, just throwing that option out there.
But, between your two choices up top is go for the lm7 block over the ls1 block if your starting out without any motor.
Just curious, what car is the motor going in? There are lots of ways to offset the added weight of the iron block
I don't really see how a 6.0 can be had for the same prices. I'm no expert but my opinion would be that you could get an LM7 for roughly 500 bucks. I have yet to see a 6.0 go for under $1,000 that wasn't completely ragged out.
I'm thinking of going with the LM7. Now, if I build it up to a 383 stroker, what are most people using as far as H/C/I to reach my power goals. Keep in mind I may want to run nitrous one day...
-Michael
#11
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You might spend more initially for a 6.0 but in the end, it will balance out.
I'm assuming you have nothing but a blank slate to start with.
Consider this. Pick up a 5.3 for 500 bucks. Spend roughly 600 in machining, then the rotating assembly. Now you have a 383 with stock 5.3 heads.
Or, you pick up the 6.0 for probably 1k and put probably 300-400 in machining. Plus rotating assembly and a better set of 6.0 heads. After all is said and done, you have more power for roughly the same cost invested.
Now, that being said, the iron 383 will suit you fine. I just want you to understand my 6.0 argument.
I'm assuming you have nothing but a blank slate to start with.
Consider this. Pick up a 5.3 for 500 bucks. Spend roughly 600 in machining, then the rotating assembly. Now you have a 383 with stock 5.3 heads.
Or, you pick up the 6.0 for probably 1k and put probably 300-400 in machining. Plus rotating assembly and a better set of 6.0 heads. After all is said and done, you have more power for roughly the same cost invested.
Now, that being said, the iron 383 will suit you fine. I just want you to understand my 6.0 argument.