im going from a stock 48mm to bbk 58mm,

can i install the 58mm without porting the intake? if so can i do this on the car? ive heard about the oil soaked rags trick then suck the shavings out with a shop vac before taking them out,

but is that really safe?

and would it be better to pull the intakr completely and just port the whole thing runners and all

 

Pulling the intake is not that big of a deal. Sure beats doing a ring job because one little piece of aluminum made its way into the cylinder.
Not to mention while it's off you can port match the runners to maximize the benefit. That said, there is not much gain for a bigger tb unless running a very large cam and turning 5k+ rpms all the time. Chances are it will cause idle issues and tip in throttle stumble otherwise.

 

The 95 intake might already have bigger ports than the heads, I would not port the runners unless you have it done with the heads. Even then the gains from intake porting are pretty minimal on most applications. We have seen over 420rwhp NA from a stock shortblock with unported intake and good heads.

 

I put the throttle body on it without porting it. Untill i can have the time to take the intake off.

Then port and paint it

Should i remove the bridge in the middle? And leave a hump for the hole at rhe bottom or just leave it in? Also can anyone direct me in how to port the runners correctly?

 

Does the tb open completely when bolted to he stock manifold?

All you should do s enlarge the holes in the manifold. Don't remove anything...there are passages, etc in there.

Don't bother porting the runners....you won't gain anything..

 

Yeah it opens fully. Thats what i was worried about myself.

The blades are sunk into the throttle body pretty deep so they open perfectly. Just wish
I knew what to do porting wise.

Intake on or off is what i mean

 

...

 

Did I give improper advice?

 

No...after you suggested he not port anything (which is correct) he continues to ask what to port.

 

If you look closer his question is intake on or off. I personally would lean towards off yet I understand the temptation to do it in place. I have a thread loyd elliot posted on porting if you are interested in that as well as most people selling ported intakes gasket match rather than match the heads or keep it smaller. I feel loyds way would be a good way to go for a do it your selfer.

 

A 58mm throttle body is not going to help you with you current mods, and may in fact slow you down alittle. If you are really wanting a larger throttle body, go with a 52mm one. I have one, and its one of those things the but o meter feels, but thats about it. 58's are really necessary on 383 engines.

hth
andy schuck

 

Engine dyno testing on my 381ci setup showed that at 500 flywheel HP the 58mm TB was flowing all the air the engine could consume at 77% open, and opening it further didn't change anything significantly. Back calculating, it shows that a 52mm TB would have been adequate, and the 58mm TB was overkill.