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Discussion Starter #1
ok so if I just wanted to tare apart the i67 and build it good then put it in my car without the supercharger (mayb the turbo instead) what parts should I upgrade like the cam and??????
 

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It all depends on your power and usage goals. The L67 is pretty stout in stock form but the pistons are the weakest part usually only usable until around 4-450 hp. Try to keep the rev limit within the stock balance spec of 6300 or bearing failure will likely result unless you get the rotating assembly balanced.

Ported cylinder heads are a key mod, as well as a turbo cam if you're looking to make a nasty turbo engine, and the stock timing chain fails with the higher spring pressures used with ported heads set up for the bigger cams so a double timing chain would be useful. ARP fasteners are usually a good investment when you are going 300+ and you have the engine apart already. There's a lot of information here if you use the search function this has been covered better by other people with more experience than me with building for turbo.
 

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yes, if you don't intend to cam the engine in the future. I have the Yella Terra rockers in the ratio you mentioned, they add lift to the stock cam profile so the powerband is the same range only stronger. Having the 1.8 ratio instead of 1.9 is nice since the stock springs can be used without chancing valve float at higher RPM's.
 

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Discussion Starter #5
so should I just get the heads done and change to the 1.8 rockers with new pistons or do I need to do more
 

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what are you shooting for in terms of power? whether you need pistons or cylinder head porting depends on your goals.
 

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you would still be safe with all the stock internals, ported heads help lessen the boost needed to make power but you should easily be able to hit 300-350 hp with the stock heads and a turbo


now that being said, i have owned a supercharged and a turbo car now, and i prefer the instant power from the supercharger hands down, if you have an automatic it's not a big deal having a little turbo lag off the line, but if you have a manual a supercharger provides nice instant power after each shift.
 

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Discussion Starter #10
so where can I get turbo headers I just cant find them I wonder if grand national headers would fit and the i67 is dbc and my car is dbw so is there more to converting it than just changing throttle bodies
 

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Discussion Starter #11
so forget the turbo , if I go natural from the ground up do I need to replace the crank? what kind of heads, pistons? does it already have roller lifters? what about the rockers? and especially the heads, what all do they need done? if I got the cash how fast can I make it naturally aspirated or maybe with a 100?? shot too
 

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Honestly, it's difficult to make a naturally aspirated 38 to go above 300. The mods would be extreme, such as very aggressive camshaft, and a high stall converter to go with it, extensive head porting by a professional who can test flow on a flow bench, high compression pistons, a full balance job, and probably bored out. Even with all that, you'd be hard pressed to make 300 whp. Meanwhile, you could do half that, and make 300 hp relatively easily if you keep it supercharged. Plus, it'll be twice as fun to drive.
 

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Honestly, it's difficult to make a naturally aspirated 38 to go above 300. The mods would be extreme, such as very aggressive camshaft, and a high stall converter to go with it, extensive head porting by a professional who can test flow on a flow bench, high compression pistons, a full balance job, and probably bored out. Even with all that, you'd be hard pressed to make 300 whp. Meanwhile, you could do half that, and make 300 hp relatively easily if you keep it supercharged. Plus, it'll be twice as fun to drive.
this.
 

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Discussion Starter #14
so what kind of supercharger do I get or do I just try to use the stock one and move the t.b.
 

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no sense meddling with the factory bottom end when you're just looking to get around 300, ARP rod and main bolts would be a good precaution in the long run if you can afford them.
the Gen 3 m90 would be a good starting point, you will have to move the throttlebody or modify the firewall for it to fit
the gen 5 m90 is a better, more efficient blower, but it is longer from what i've seen and that may make things harder (or it may not i've never seen a gen5'd rwd 3.8)
 
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