Looking for engine help ideas...

[cngodfather]

I like the advice ! I think I will definitely do these changes. Something else I will have to do is change the fuel delivery. I have always hated TBI and carburetors are ok but can get finicky in the cold Indiana winters. Any thoughts for an inexpensive fuel injection upgrade?

 

[cngodfather]

I did it again. SMH. I did not read the last two posts before I replied. How do you retune a the tbi computer? I have done FAST brand tunes with their software but never a factory computer. Will I need a computer with windows 95? Lol!

 

[PlayingWithTBI]

Will I need a computer with windows 95? Lol

No, there's software that is actually being supported and improved currently but, if you have Windows 95 (and it didn't crash on Y2K,lol) by all means have at it. I'm using TunerPro RT v5+ (freeware but suggest contribution) and an ALDL cable for OBD1 TBIs ($60) on Windows 10 OE
http://www.tunerpro.net/
http://aldlcable.com/aldl.asp

Enjoy!

 

[PlayingWithTBI]

Also, depending on your PCM you'll need to change your EPROM to an EEPROM (like an SST27FS512 flash chip), a lot easier flashing than burning. I use a Moates Burn2 to flash and read the chips
http://www.moates.net/burn2-chip-programmer-p-197.html?cPath=94

Or you can go to emulating hardware (same website) or EBL Flash2, the only problem, if you have an auto trans you'll need to keep your OE PCM for it and add the EBL to it.
https://www.dynamicefi.com/EBL_Flash.php

All kinds of fun Playing With TBI, enjoy!

 

[L31MaxExpress]

I want to foot stomp this. TBI guys are especially notorious for neglecting the tune and there's a lot of power and driveability locked up in there once you make them breathe.

Lots of power to be unleashed even on a stock engine. I got a TBI 350 up to 200 hp at the tires with the stock cam and heads.

454 tbi on an open center spacer, edelbrock 3704 manifold bored to 2", thorley tri-ys and 1.6 rockers with a good tune.

Put a stock 1996 Vette LT4 roller cam into it and made 250 rwhp.

 

[Erik the Awful]

Vortec heads flow too much for a TBI, and you went to even better flowing heads. I'd ditch the TBI outright, and if you're doing that, why even bother with a small cam? Go with .500 lift and a moderate duration. Otherwise, why the big heads?

All that said, I went with the following in my '99 Suburban, now going into my '89 Stepside:
350 4-bolt main block, honed, but no overbore
Factory Vortec heads, 062 castings, no porting, no machining
Factory crankshaft
Speed Pro H345DCP flat-top hypereutectic pistons - 9.5:1 compression ratio
Speedway Motors 5140 steel I-beam rods, 5.7", bushed pin
Lunati 20080720, advertised duration 262/270, lift .507/.515
Factory roller lifters, dog bones, and spider assembly
Chevrolet Performance 12499224 LS2/LS6 valvesprings
COMP Cams 787-16 steel valve spring retainers
COMP Cams 648-16 race valve locks
Proform Parts 66914C extruded aluminum roller rocker arms

Video of it running in the Suburban:

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I had it running, but pulled it back out for a minor issue. I have it in the stepside, but I'm waiting on a Vortec fuel pump from RockAuto to get it running. I'm going to fire it up with the TBI adapted onto a Summit dual-plane Vortec manifold, and I'm hoping to get a Holley Sniper system sometime in the near future.

I went with short duration because of the lack of upper-rpm with the Vortec heads, but that's not an issue with your heads. However, being a heavy truck with big tires, you'll probably want to keep a short-ish duration.

 

[PlayingWithTBI]

Vortec heads flow too much for a TBI

Hmmm - these heads flow better than Vortec Heads and are for TBI.
https://www.summitracing.com/parts/sum-162108/overview/make/chevrolet

 

[Erik the Awful]

Just because you can drink a milkshake through a coffee straw doesn't mean you should do it. I'm bolting a TBI on my engine to get it running, but I know it's a bottleneck.

 

[L31MaxExpress]

You can make ~330 hp with a small block TBI. You can make ~450 hp with a 454 TBI. You can make 660 hp with dual small block TBI units run with an EBL. You can get over 900 hp out of dual big block TBIs.

TBI is not a restriction, especially with an EBL with the injector driver board for dual TBI units added. Performer rpm air gap dual plane dual 4bbl manifold with 2 small block TBIs will fuel a wicked small block.

 

[PlayingWithTBI]

I'm bolting a TBI on my engine to get it running, but I know it's a bottleneck

Not really;
Here's the one I have on my 350 (46mm) - 650CFM. I was running flow matched 61LB/Hr injectors at 28PSI then I switched to 90LB/HR (from a 454) @ 16PSI with the EBL Flash2, still running ~78% DC in the injectors WOT at 5200RPM
https://www.ebay.com/itm/46mm-PORTE...837306?hash=item3d963196ba:g:mpwAAOSw2xRYWVJj

I'm using the Edelbrock Performer 3704 bored to 48mm
https://www.summitracing.com/parts/edl-3704

Look at this calculator for Carburetor Sizing for NA Engines. EDIT - plug in 350 cu in and 6000RPM see what you get.
https://www.tciauto.com/racing-calculators