welp, lets just say a very strongly built and running 406 TPI with SLP runners and a larger aftermarket plenum as an intake setup, with the stock throttle body and an SLP air foil bolted up to it with the stock intake tube with a k&n filter on the end as an intake setup.
Now my belief is that the stock throttle body is a twin 48mm like on my LT1.
Would it be recommended for a switch to a twin 58mm throttle body with this type of engine?
As it is right now its making around 400 hp and 515 tq to the wheels with only headers and the stock exhaust as the exhaust setup. I would think that a 58mm tb and a Flowmaster cat-back and maybe a 3" cutout would be awesome compliments, but I wanted some input.

 

A 406 making 400 HP would warrant the 58 mm TB. Yes the stock unit is 48 mm.

Some people find that the 58 mm causes a stumble at idle to low throttle. Although with an engine making that much HP, I don't think it would be much of a worry.

When you say larger aftermarket plenum, do you mean a ported stock unit?

 

I'm not sure, the owner says it has a larger plenum and that's all he said, it looks like the factory plenum to me though:

 

Have you done the TB water bypass mod yet?

 

nope I haven't yet. I did it on my LT1, but haven't got to it yet with this motor, was gonna wait to see what I wanted to do with the throttle body in the first place.

Are there any recommendations as far as TB's go?
Which is the better TB? BBK or Holley?

Also, is the computer going to have to be flashed?

 

Are you running the stock TPI intake manifold? If so getting the 58mm throttle body will not do you that much good. Have the SLP runners been opened up any?

 

no, the intake manifold or plenum is an aftermarket piece. I can't tell you the brand though cause I don't know it. I do not know if the runners have been opened up any either.

 

If that is an aftermarket TPI manifold such as the Edelbrock you need to have it opened up(ported). Same with the SLP runners. You will see a big power increase. Also if you get the 58mm throttle body it will have more of a benefit with the other pieces ported.

 

good point, thanks!
I'm gonna focus on the exhaust tho before I do all the intake work
stock muffler isn't gonna cut it lol

 

I have the same runners. I just added the TB bypass today. Easy job. My motor is around 400HP and 430lb/ft. I am using a 52mm TB as that is what Scoggin Dickey said worked best for this engine. http://www.sdparts.com/product/SD360...ripEngine.aspx

So I would think you will need a 58MM with all that torque.

 

Yes do the exhaust first. Then when you do the intake you see bigger results. The air comming in has to get out.

 

thanks for the advice!
what's your engine setup like?

true dat buddy, I'm leaning towards a Flowmaster system (that's all I've ever used on any vehicle lol, can't be beat!) and maybe an electronic 3" cutout, might be loud enough the way it is tho with just the cat-back...

Then would come the throttle body, I was looking especially at Holley, whatcha think? I like it for the name and billet aluminum...
Summit's Holley TB

Anyone have any ideas for intake before the throttle body?
cuz the stock intake tube is SUPER restrictive ans no-one makes a CAI or anything for this car. I was thinking about just putting a filter right on the end of the throttle body b/c I don't have to worry about an MAF...trick is finding one lol

 

Doesnt look bad to me,I think you should keep the black plastic piece that goes to the T/B and stick a filter on the other end of that. You want air thats cool,away from the engine.

P.S. Whos idea was it to put a weak *** intake on a trick 406?

 

Here are some filters if thats what you meant. But these will only work with speed density cars. Not MAF.

http://www.jegs.com/webapp/wcs/store...46165_-1_11175

 

Its already got a K&N cone filter on the end of the intake tube, but the tube is still restrictive tho
that was the previous owners idea, the guy who built the engine, I'm sure he had his reasons tho, maybe to make it more streetable...but idk

THAT"S exactly what I was looking for!
It'll work for me, cuz I don't have an MAF.
right?