In a earlier thread I asked wich is better ls1 or lt1 the most common thing I heard back was that the lt1 lacked in top end grunt compared to ls1 is this true with lt4?As I am thinking seriously about installing lt4 kit from summit if I buy lt1?Also this is the combo I am thinking for my street srip monster lt1 with 383 stroker,lt4 kit and vortech S/C sound good?I want 10sec street car.
All that is possible if I dont buy ls1.I am going to need new rear end 12bolt nine inch any advice?Will corvette rear fit etc,used is better.Thanks guys.

 

The LT4 will be faster in the long run if you plan on doing major modifications to it

 

Shacleford, its just I live in Japan so I cant muck around to much so the bolt lt4 kit with hot cam looks like a good idea at summit they say 425hp+.Why will the Lt4 be faster in the long run?

 

All of the responses thus far have been incorrect/misleading.

The LT4 was a 330 hp motor. If you add the hotcam and headers, then that's where you get 425+.

With the LSx platform, you have much more to work with: much more technology and a completely re-engineered engine. Unless you have an LT1 F-body, I'd go with an LS1 setup any day of the week before I went with an LT1 setup. More power with less modifications. Most LT1s have trouble putting down what I put down to the wheels with heads/cam and I only have a cam. You just aren't going to see 500+ rwhp heads/cam or 550+ rwhp hyd-roller stroker LT1s like you will with LS1s.

In any case, if you already have a LT1-based F-body, I'd get the heads done by AI, stick in a nasty cam like the CC306, or go all out and build a stroker motor or a blower motor. You aren't going to put much of a blower on a 10.5:1 engine, so if you go that route, you'll need big CC heads and a bottom end to support it. A 383 with an LT4 intake, 205cc/76cc AFR, forged bottom end, and a D1SC should be fun. You just need alot of money.

 

Close but incorrect kraest. The LT4 is a 350 horsepower engine. I've seen countless grand sport dyno's that back it up.

 

As far as your question about the rear end goes, yes you will need a 12 bolt or 9" if your planning on a 10 second car. Our weak 10 bolt rears are no match for the torque needed to be put down for a 10 second car. Hell, just bolt on's and drag radials can break them. :blah:

 

I doubt this claim. That's what the Z06 dynoes.

Considering cresting 400 at the wheels with an LT1 is impossible for most people due to knowlege/finances, I don't believe the LT4 with slightly modified LT1 (GenII) heads, and a small stock cam would do 360.

I think you're confusing several ideas here. Such as the popular LT4 HOT cam install. Even an LT1 with the LT4 HOT cam will not easily dyno 360 hp, and this would be a more powerful motor than a stock LT4 engine. Just look at the cam specs if you doubt this.

Ben T.

 

EngineerMike's (unofficial) 9 second camaro still has a 7.5" rear. ...but this is not the norm for most. Most cars will need a super hard launch to trap good times, and the puny 7.5" doesn't like super hard launches too much.

I'd suggest a better rear too. It's your pick from three options.

Ben T.