Newb here, building TBI-vortec head, 383

Newbie from Vancouver, WA here. First time posting but have been lurking for a while, though and also been working with Dave W as I'm lucky to live in the same town. He's burned me a "start up" chip for the build described above. More specifics:

- Vehicle: 1991 3/4 ton 4x4 suburban. Last of the "square bodies" and only one with a 4L80e tranny. Dave W had tuned it for the PO as well.

Engine that's about ready to get dropped in:

- block from a '90 3/4 ton burb, 4-bolt main.
- Eagle stroker cast crank
- bored .030 over, true 383 cubic inches
- KB pistons
- stock 5.7 rods, resized and new bolts
- vortec 062 heads, locally rebuilt
- 1.6:1 roller tip rockers
- L31 cam and full roller valve train taken from a core vortec 350
- GMPP vortec spread-bore intake

Induction:

- reman and bored 46mm TB
- 454 injectors, 70 lbs/hr (per Dave W recommendation)
- spread-bore to TBI adapter from early 454 truck
- EGR delete

Engine just about fully dressed and ready to go in, bracketry for top end accessories on GMPP intake has required some creativity. Attachment 12780Attachment 12781Attachment 12782Attachment 12783

A formal :welcome: from gearhead-efi.com

dave w

Thank you, Dave! A question for you, related to your last email to me. Thought I'd ask here so others may benefit. In that email you mention a "knock filter module" - what is that? and does a '91 TBI have one? I know there is a knock sensor, but that is a one wire connection into the harness and I wasn't aware of any other components to that system. Perhaps that is the same as the Electronic Spark Control, ESC, module? I'm thinking GM eliminated that module between '90 and '91 and just had the ECM take over those duties? Pretty sure my '91 doesn't have one. The bracket that hangs over the PS valve cover only has the EGR solenoid on the bottom and nothing on top. But I had a '90 TBI parts rig and that did have the ESC module on top and EGR solenoid on bottom. '91 in running condition before I took anything apart: Attachment 12790

Bracket from the '90, with ESC module on top: Attachment 12791

I had a feeling some slightly later model stuff (LT4) had a module that helped the Knock sensor compensate for the noise made by factory installed roller rockers.
I don't believe it's compatible with early 90's PCMs though more of a late 90's thing, I'm sure Dave will know.

The 16147060 is considered a "Second Generation TBI Computer" because it uses a Memcal that includes, limp home mode, the PROM Chip, and knock filter.

dave w