Ultimate TBI on 7.4?

[unstable]

Hey folks...
I'm waiting on getting things lined up for the 454 rebuild, in the meantime I'm driving the 89 1-ton around with the tired motor. Trying to keep myself occupied, I figured I might tinker with the TBI. I've been reading up on the various modifications, spacers, grinding off the lip around the bores, etc. etc.

I picked up a gasket set yesterday, figuring that if I had time I might pop the TBI off of the truck and go to town...but as I peered at the system, it didn't look like the other pictures I had seen. Yes I know the 7.4 / 454 is the biggest of the throttle bodies that went on these rigs, but I figured the mods would be aout the same. I don't see the lip that I'm supposed to grind...

Can anyone point me in the right direction?

 

[90'rado]

Post some pics if ya can.. I've googled around on 454 TBI's since I've never had one myself. It looks like maybe there were some GM 454 TBI units that already had no lips around the throttle bores.

 

[unstable]

I hope these are acceptable...best I can do with my phone...my wife stole the good camera for the weekend.

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[90'rado]

Yeah you have no lip to grind down around the throttle bores, GM probably realized they could squeeze more air into a 454 w/o it being there.

 

[unstable]

Any other mods that would be worth doing still?

 

[90'rado]

.....

 

[unstable]

when I went to the parts store to get gaskets they had 2 gaskets for the TBI...it has an "adapter" of some sort as you can see in this picture: http://www.gmt400.com/forum/attachment.php?attachmentid=1397&d=1272753657 it has a hose going into the base of it. I haven't bothered tracing the hose but if I had to guess I'd think that maybe it's coolant or something.

I don't have a ring for the air cleaner but I have read about the salad bowl thing...I will check into doing the pressure regulator piece, maybe polish the bores some while I'm at it and give her a general cleanup.

 

[90'rado]

.....

 

[unstable]

I'm not sure what kind of bore is on this intake...like I may have said I bought the gaskets for the TBI and it was a two piece ordeal, one to the adapter and the adapter to the manifold.

Once I get the fuel tank and lines squared away I will pull that thing apart and take a better look, maybe snap some photos. I don't think the TBI is going to stick around for very long anyhow. My engine builder said I should be looking at 800-850CFM for the motor we're putting together.

 

[90'rado]

The stock 454 two inch TB flows 670 cfm @ 3 In/Hg. The BBC TB can be bored to 850-900 CFM.