TBI intake manifolds

[Mastiff]

I currently have an adapter plate on my intake on my converted carb 350. I thought it might be slick to put an actual TBI manifold on, but I'm realizing the bolt patterns may be different (if not more stuff). Is it true that everyone just lives with adapter plates when they do these swaps?

[dave w]

Typically SBC iron heads manufactured between 1987 ~ 1995 have the center bolt holes angled at 72 degrees vs. 1986 and older SBC iron heads with center bolt holes angled at 90 degrees.

The TBI air fuel mixture is called "wet flow". Typically a high velocity wet flow is desired for a daily driver / street application, to avoid fuel puddling inside the intake.

Typically a dual plane carburetor intake (which is also wet flow) with the TBI adapter plate has sufficient wet flow velocity for a daily driver / street application.

[Mastiff]

Thanks. I have no complaints about performance, just looking to clean up my setup for the fun of it. Also struggling to find a good place to mount an external coil. I'm surprised nobody makes TBI conversion manifolds, given how common this swap is.

[PlayingWithTBI]

I'm surprised nobody makes TBI conversion manifolds, given how common this swap is.
If you're talking about using Vortec heads, Chevy Performance makes a TBI manifold for them - just sit down before you look at the price :yikes:

https://www.summitracing.com/parts/nal-12496821

[1project2many]

Even GM wasn't above using an adapter to run TBI. The early Big block TBI trucks used a water heated adapter on a carbureted TBI manifold.

If it runs well, stay with it!

[Fast355]

Even GM wasn't above using an adapter to run TBI. The early Big block TBI trucks used a water heated adapter on a carbureted TBI manifold.

If it runs well, stay with it!

I have a couple of OE marine or industrial designs as well. One to a 2bbl 2GC pattern and a 2nd to a 4150 4bbl pattern. The 2 bbl has an open center, the 4bbl is divided with ridges machined into it and long oval ports. Both were setup for 2" bore marine and industrial TBIs. Even the 4.3L had a 2" bore TBI in marine and industrial applications.

[Dieselsj]

Even GM wasn't above using an adapter to run TBI. The early Big block TBI trucks used a water heated adapter on a carbureted TBI manifold.

If it runs well, stay with it!

This right here.

My 87 7.4 used an adapter on a factory spreadbore intake. I went to an Edelbrock 7.4 TBI intake and really wasn't happy with it. I went back to a 4-bbl intake with the adapter and it seems to like it a lot more.