I am looking to build an Twin Turbo Ls1 for my 67 nova. I have bought the engine which is out of an 98 camaro convertible. My plans for the car is as follows. It will be an street/strip car that will do a fair amount of street driving and some drag runs as well. The rearend is an 9" ford and is build to handle around 800hp. The transmission will be an TH400 build to handle 850hp, this is primarily chosen because of cost/reliability. Because of missing OD i will aim for an rather low ratio in the 9" propably something around 3.00-3.27. My goal will be delivering 800hp as this is the limitations of the 9" and TH400. I would want the boost to come as early as possible to have as much low-end torque as possible and still make the 800hp. This will also be neccesary in order to launch the rather low ratio rear end. The engine will be having h-beam rods, forged dished pistons, higher volume oil pump, double roller chain etc. and i think i will use truck manifolds for the turbo's. I have thought about using the edelbrock performer intake, but i am not sure whether i will gain anything on that account compared to the standard LS1 intake? It looks to me as if the performer intake will flow better and distribute the air more nicely? I am not sure how much work there needs to be done to the head in order to deliver the 800hp. I will be replacing the valve springs and thought about replacing the valves. But is this neccesary to reach 800hp as an reliable setup? If it is possible i am not aiming to pull higher revs that stock and i might keep the stock cam onless someone says otherwise.

My main question is on the selection of turbo's. I have been looking at buying 2 of these, will they fit my needs or do people have a better choice?

Precision SC3431E

Specs are as follows:

T3 .48 rear housing

5 bolt or 4 bolt discharge (your choice)

E-compressor cover (.60ar)

capable of over 535 hp

This made up for an rather long introduction, but i hope there will be someone that can give me an hint whether i am on track with my project. Please ask if you need information. By the way i am from Denmark, Europe so there is quite i timedifference which means that i might not reply right away.

 

I know you want make boost early but you may want to go with a .63 a/r turbine housing and definitly a stage 3 or higher wheel. the gears are fine you wont have to fight wheel spin as much. lots of fuel needed for 800 hp.
good luck you've got the right engine and plan. I dont think you'll hit 800 with a stock cam. but hey give it try and let us know.

one other note if your going forged pistons and rods, you can really gain from the .63 twins that flow more, and with a little 75 or 100 shot of nitrous out of the hole, you'll never know you lost some low rpm boost from the bigger housing.