In the process of planing our next years build. Plans are to run in the 7s with a "street car" (although i dont drive it on the street). My Engine is going to be a 408 and 91mm. But i got to thinking, would it be better to run twin turbos? I know its going to cost more, i just want to have a powerfull efficent car. Any input to get me in the 7s would be great. I am running a th400 trans.

 

98mm..
Fireball ran 7.9 with that turbo and small LS2 364ci ..

But if you want mid 7s then 106

 

Your first problem with running a big single capable of 7 sec passes is packaging. Specially if you want it to appear to be a strweet car. Packaging presents 2 problems. The first being the actual thumper itself and the second being the 5" DP that you have to get out of the engine compartment.

I don't think that the 408 w/ 91mm combo would get you there unless you plan on being sub 3K# anyway. We got LS2Formula JUST into the 7's so far and that's with twin TC78's at 3500#'s. Much easier to package the twins.

 

Give us a call we can help with the setups. Twin or single can be done....just depends on room

 

I would say you would have to up that to at least a 98mm for 7's. I personally prefer a big single, less maintenance and initial cost. I'm going 106 on mine, but i'm just putting the downpipe right out the fender since I don't really care about the whole street car look and i'm shooting for bottom 7's, but if you couldn't fit a 5" dp past the kmember you could always split to dual 3" to get it back there.

 

step one...ditch the T400

 

I was waiting for that .... You don't think th400 can run 7s?

 

A Precision Pro Mod 94 will get you in the 7's with the right combination-this is probably the smallest single capable of it.The physical size is a little smaller than a gt4788.A pair of 76's would easily do it as well.Your going to need a very well built engine and def would scrap the th400.

 

Depending on what's done to it it could hold, but that 2.44 first gear will make life harder with the launch, I personally am a glide guy ever since I swapped to the glide from a t400 and picked up 2 tenths and 2 mph! But a good glide or a th210 will do the trick.

 

Plus one on the Rossler TH210XHD.

 

Didn't vette dr run low 8s with a th400?

 

Why do you want a non "street car" "street car". Doesn't really make much sense. Are you just trying to avoid the race car look?

"street car" often means heavy too.

 

Sorry, I mean street trim, don't care what it looks like. NMCA true street is what I mean

 

Glide + gearvendors.

 

There are many other gearsets (besides stock 2.48 and 2.10) for Th400s. And there are also many other reputable trans builders besides Rossler.

 

T400 are limited to stock cases...I like the aftermarket support for PG...

I know Phil and I both run ATI trannys...

 

A 91mm can do it with the right combo and right wheel.

91mm EXT-R should fit the bill....

 

Damn. I need an upgrade. How much more can that wheel support over the ett wheel?

 

Thanks Doc. What does that thing max on at? Who makes the 91mm EXT-R? price?

 

EXT-R wheel flows 10% more. . They are 11 primary blade CW's, no secondary blades. Higher pressure, and more flow at lower shaft speeds. Also the wheels are 40-50grams lighter due to slimmed hub line and thinner blades as well as total blade count is less 10% minimum.