If you got the compression down to 9:1, you could easily achieve those numbers with a setup like I use. Magnum exhaust manifolds and a Borg Warner S475 ($650 turbo) would get you there easy. You MIGHT be able to do it with one of the cheaper Chinese knock offs, but there aren't a ton of them out there with large turbine (exhaust) sides for a motor as big as a 408". You might choke the motor on the turbo before you get where you want to go powerwise.

Poly... respectively... A 71/75 would not make 1000hp on that motor, and you can find something that would work for a lot less then $1600.

The 408" needs quite a bit more then a 75mm on the turbine side to make 1000hp, and the 71mm compressor side would be absolutely set on kill to feed a 408" to 1000hp.

If you wanted that much power, The S475 I suggested with the 75/88 would be a good choice, or if you wanted more the Borg S480 with the T6 can be had for about $850. This has a 80mm compressor, with an 88mm exducer also on the turbine... Much better match for a bigger motor looking for 1000+hp.

The borg stuff is slightly on the heavy/large size, but they are about the best bang for the buck out there, and they are about bullet proof as far as turbo's go.

About the cheapest turbo off a factory rig would be off a Detroit. Its a Garrett TV8101. The one I had was 82mm. They will get to the 1000 hp range. Would work well on 400-500".

Viren (VS racing) is obviously getting his stuff from overseas like other distributors, but I have to say working with him he's a very good/honest person. Not a guy I'd be afraid to buy from. His S480 knock offs are about $50-$100 cheaper then the real thing, BUT come with a billet wheel too. So it really depends how good the billet wheel is if you want to risk buying one. Really too new to tell how much better they are then a regular cast wheel S480.

I have considered selling my single and going with a set of twins from VS was looking at the billet 78s. But I am also considering starting over with a R5 so I don't know.. lol