So my friends and I are working on coming up with a build for a sleeper car. We have a budget of around $35-45k and have people that will swap the engines and do everything else. The questions we have are related to the LS engines. Specifically the LSX 454R and the LS7. We want to put twin turbos on it but we have concerns over price and manufacturer of the turbocharger. Plus we also need to find a transmission for reasonably priced that will handle somewhere in 900-1k HP range. First off which engine would be most efficient as far as cost and power. We are open to suggestions on a body because we haven't found one that fits our needs. Preferably AWD, but if not RWD. We have an idea of what we want as far as specs but we would like to hear some ideas.

 

Crown Vic would be a good sleeper

 

Nobody expects a Supra to be fast. I'd do that.

 

I think that you're into a flawed plan with the LS7 and LSX454R. The compression in the 454R is super high and it makes great power to begin with. You'd be at almost no boost to make what you want which would be good since it's 13:1. I'd be a lot more inclined to think you'd want 9.5:1-10:1 CR.

For 1K with a decent budget, I'd be looking at:
~400 CI, maybe even less depending on octane requirements. You've got people doing this on 4.8Ls these days with E85. 400 would be a pump gas build or thereabouts.
-9.5:1 or so compression
-Custom cam, there's a few people out there who do these
-L92 top end with some porting or aftermarket equivalent.
-Beefiest rods you can get, good pistons
-Stock cast crank has been run that high, with your budget lean aftermarket or forged IMO.

In terms of the chassis, there are tons of options out there. Are you looking to keep it GM? If so, it could be a truck (Colorado/S10/full sized,) AWD Astro Van, SUV like a Tahoe or a Bravada/Blazer/Trailblazer SS. Otherwise just keep your eyes open. The thing I'd be keeping in consideration is to put a trans behind it that will suffer an engine like that you're talking a glide, TH400 or 4L80E depending on weight. The transfer case options for a true AWD behind a 4L80E are limited, so I would think you'd be into a hi/lo 4WD case instead. Some have converted the Syclone/Typhoon cases to 4L80Es with different inputs or output shafts.

In terms of turbocharger, I'd be looking at a single Borg S400 series or twin S300 series, perhaps one of the GT47 series. Depending on the unit you pick you'd likely end up with head room.

 

anything ever come of this?