I am putting together a 383 for my impala to replace my 355. I want to switch over from supercharging/nitrous to twin turbos (goal is 1000 whp with 25lbs boost), and i had a few questions.

First off, does anyone know where to get a new 2 bolt lt1 block (need 2 bolt so the splayed caps will work)? I cant seem to find one and I would really like to use a new block for this project.

Here is the rotating assembly I am considering, any input on these products would make me feel better seeing as how they aren't cheap.

crank 3.75 stroke either callies magnum or lunati pro series
rods 5.7 inch billet, either lunati or oliver
pistons JE severe duty blower/turbo pistons with 8.5 cr.

The turbos I am REALLY interested in are the Garrett GT40r dual ball bearing turbos. They seem to work real well at the PR and the flow rate I will be needing (3.0, and 55lbs/min each). Has anyone messed with these units? I dont HAVE to use the ball bearing units, but I prefer too, if for no other reason but to waste some money, LOL. I want the car to start building boost as soon as possible, and am willing to give up some top end power for low end grunt and a decreased spool time.

My friend thinks I need to go larger with the units, but I want to use the SMALLEST ones that will be able to do 1000whp thru a turbo 400.

Thanks for you help.

 

Anybody have any input on the gt40r turbos I am interested in? I think they would work well, but dont want to make the purchase without some input from people with better knowledge of these things than me.

Any help would be appreciated, Thanks

 

I looked into those for my turbo project (and several others), but the ball bearing system is just too expensive for the returns. My builder and I finally decided on a pair of PT-61s. They're relatively inexpenisve at around $620 a piece. They should also be capable of supporting over 1100 horsepower. And you can get them in a .68 AR housing which should make them spool fairly quickly.

 

I'll take a 'sound' used block over a new block, any day. Overbore requirement, not an issue.

 

I think SleeperZ28 used those GT40 turbo's for his 1000+ RWHP LTx motor. Maybe he will chime in as well. The SC61's support 680 Hp a peice according to Precision. I went with these as well.

 

im using the master power t-70's, little bigger than the sc61's, spool a little later, but capable of 700 hp a piece