Porting 4.5L Inlet Manifolds - Is it worth doing?

[A and K Cerbera]

While working on our Cerb 4.5L AJP V8 engine I had to take the throttle bodies off. In doing so, I took the opportunity to look more closely at them. In the top of the TBs, there is a step around the inside where the injectors are located.
Is there any benefit in porting and removing the step?





Also there is the end of a bolt sticking through the wall of the TBs. Should this be shortened so the end blends in with the inside of the TBs?
When looking into the bottom of the TBs there is a lump. Is there any reason why one should not remove that lump and make the aperture more round in shape?





Finally I measured the TB's and to my surprise the top aperture measured 46.5mm and the bottom aperture measured 40mm internal diameter and 39.5mm i.d. where the lump is. The inlet port in the cylinder head is a fraction less than 40mm i.d.



I'm impressed with the 4.5L AJP. These engines can produce over four hundred horsepower through such a small aperture.
I have a lot to learn. I would appreciate your thoughts.

[A and K Cerbera]

I've got the exhaust manifolds off and can see the witness marks where the exhaust gases hit the flanges.





Based on your comments, it looks like we will be doing a standard spec rebuild with the addition of ACT exhaust manifolds and a short induction kit.

Thanks for your thoughts