I am looking to put together my 90 rs with 400hp. I want to the engine to be carb with a 5 spd. Wanted to know if anyone had exactly what they have done to achieve this, so I know what I need. From what I have read on this site most of the members are very knowlegable and seem willing to help the new guys.

 

the easiest way in my opinion to get 400 hp NA would be a 383, around 10.5:1 CR, with half *** decent flowing heads, you would need a cam thats around .550" lift and around 235* @ .050" (rough estimate) more than likely a taller single plane intake, the usual 750 DP carb and headers

tuned right that setup should easily make 400 RWHP and run on pump gas

 

Cubic inches and compression are your friends. Especially cubic inches - the bigger the base you can start with, the easier it will be to hit the target number - and it will be a more driveable engine to boot.

My suggestion - find a 400ci small block to start with. If you can't find one, get a 350ci and turn it into a 383ci (requires a 3.75" stroke crank VS stock 3.48" stroke crank). The more cubic inches you have, the easier it is to make power.

After that, I would suggest a set of heads in the 190-200cc intake port size range (best ones available from Dart, AFR, TrickFlow, and GMPP). If thats a bit out of your budget, as they are expensive, then a set of Vortec heads would do quite well too. You can have a set cleaned up, machined, and modified for a larger cam for under $1000 if you find a decent used set.

Now the camshaft - One of the larger cams in the Comp Cams XE line would be good. I have the XE274 in my 350 and it makes in the neighborhood of 400hp, and its still a very driveable engine. Lopes some at idle, but its not a total pig at low speeds like the sound suggests - that would be a good cam to use.

And the rest... get pistons to make compression in the 10:1 range, a good high rise dual plane intake (Edelbrock RPM, Weiand Stealth, Holley 300-36 are good ones), and a carb in the 750cfm range. With a 5-spd I HIGHLY recommend using a double pumper carb like the Holley 4779. I have that carb on my 350 and it works great. It can cause problems with the Edelbrock RPM intake though if you can't use a carb spacer - the vacuum port for the brakes interferes with the rear fuel bowl on the carb - the other two intakes are fine though.


What I just suggested above is basically the same setup I have on my 350, and it makes in the neighborhood of 400 crank HP, and its a very streetable combo with decent low speed torque, LOTS of midrange power/torque (2000rpm and up), and still pulls hard at 6000rpm. On a bigger 383 or 400 it would be a really killer setup IMO. Easy 425hp.

 

What 5 speed? A T5 wouldn't last long behind 400 HP, especially if you use all available.

 

400 hp on crank or at the wheels?? wheels will need a very stout 383 but could be done with a fairly rev happy 355

400 on crank is walk in the park. vortec heads, any intake basically, and a cam like LT4 hotcam for a roller or XE 268 flat tappet cam for a flat tappet cam could also try xe274, one step up for more hp insurance

Thats the cheap way

my buddies LT1 cammed vortec 350 made around 350 on motor or so. LT4 hotcam is proven for near 420 actually

 

If not a T5, what other options do I have to withstand 400hp? Thanks for the input.

 

T56, Super T10 ('82 TA and Z28), various aftermarket transmissions.

 

Yes, the '93-'97 f-body V8 T56 is a good choice.

 

For 400 at the crank, it's easy. I have a 2000 r code 350 truck block, xr282 hyd. roller, vortec heads with port work, 10.24:1 comp., and a dual plane with a holley 3310. 426 hp at the flywheel. At the wheels, you will need something that would be worse on the street. It depends a lot on how you want to use the car.

As for the trans, I have to agree with the others. T-56

 

Does a T56 trany a direct replacement for the factory 5spd or is there any modifications that need to bo done in order to fit it? Thanks for replying.

 

As long as you get all the parts, its not too difficult. There are alot of posts about the T56 swap in the 'Transmission' board, its a pretty popular swap. You want all the stuff from a '93-97 Camaro/Firebird with the LT1 engine.

 

you could shell out the bucks for a tremec retrofit T56 for our cars.. i believe it doesnt need much to install other than shorter driveshaft and different torquearm/crossmember kit. all of which good mods to have

but the regular factory T56 will go in as long as you get everything from a donor car and cut the shifter hole back 2 inches

 

I guess most would agree the way to go would be to use a t56 trany. Is there anyway to rebuild the world class t5 to handle 400hp at the rear wheels? I currently have 3 t5 tranys and was hoping that I could use them to put together one tough enough to use.

 

The kit I saw a while back was around $1300, if memory serves.

You can get a full T56 take-out from a LT1 f-body for $1000-$1500.

The T5 route just doesn't make sense.

 

If I can find a t56 what years would I be looking at? I see that 93-97 will fit but I also see that a 98 is better, so now I am not sure. I also was wondering if the t56 involved any other modifications to the console, slave sylander, bell housing, fork, bearing, pedals, driveshaft, or floor pan? What else would I need to convert to a t56 besides the actual trany? thanks for replying