TBI on older 454 engine Need a quick answer.

[Vombrown]

Need a quick observation here while I decide which direction to go with the purchase of a Crew cab as my new tow rig. One of the trucks I am looking at has a '88 TBI 454 that has a bottom end noise. Don't know what it is, haven't heard it in person. What are the differences, if any in the '74 generation 454's besides the obvious port difference on the exhaust. Basically what I need to know is this, is it possible to swap the 74 engine into the 88 truck and keeping the TBI (with a new chip and new exhaust) essentially just swapping everything over.

This will help me greatly in making the decision to pull the trigger on this crew cab truck. This is the one I have been looking for....show stopper, just has a motor noise. Keep in mind the long term goal is to diesel swap this truck but for now I just need it to run and drive. Being able to swap n the built 454 from the Snow Bear will make it so. Thanks guys!

 

[SpeedlabDan]

I believe so. My 8.1 can use all the older bbc parts.

 

[Bent77]

Need a quick observation here while I decide which direction to go with the purchase of a Crew cab as my new tow rig. One of the trucks I am looking at has a '88 TBI 454 that has a bottom end noise. Don't know what it is, haven't heard it in person. What are the differences, if any in the '74 generation 454's besides the obvious port difference on the exhaust. Basically what I need to know is this, is it possible to swap the 74 engine into the 88 truck and keeping the TBI (with a new chip and new exhaust) essentially just swapping everything over.

This will help me greatly in making the decision to pull the trigger on this crew cab truck. This is the one I have been looking for....show stopper, just has a motor noise. Keep in mind the long term goal is to diesel swap this truck but for now I just need it to run and drive. Being able to swap n the built 454 from the Snow Bear will make it so. Thanks guys!

Your biggest issue in terms of the TBI running is on the camshafts. If the cam specs are identical, the computer may correct for all the other differences

The vacuum characteristics are critical

The other event is where the Ecm is looking for a VSS, EGR, or signal for the lockup

 

[dyeager535]

I'm not aware of any.

Trying my best to recall the specifics, the 454 that went into Dad's K20 was out of a mid-early 70's car (it was already pulled, believe we were able to check the suffix code) and he bolted that into the truck carbed, then swapped it over to the stock TBI from a square body with factory 454.

Putting the cart before the horse a bit, but you mentioned the chip. If/when you go down this road, and the 454 you will put under the TBI is built (even an RV cam, headers, Edelbrock Performer intake), save yourself some hassle and money...get an adjustable fuel pressure regulator (if they are out there, you can try shimming the stock one, but it takes a bit of trial and error) and the EP381 pump out of the gate. Even with those mild mods, the TBI pumps may not be able to keep up, IME.

The switching valve on dual tank rigs is a problem with high (above TBI's ~13PSI) pressure if I remember others experiences correctly.

 

[Vombrown]

The 454 I have is just a very mild RV cam. Has a slightly higher compression ratio and an edelbrock dual plane intake. If my reading is correct these are all doable with the stock setup, adapter for the TBI to intake of course. I had already planned a new fuel pump. The 454 I have is a very stout engine, all forged internals and the best of the best parts....essentially brand new ( 1,000 miles). I'm trying to rationalize dropping that 454 into the truck or doing a rebuild on the stock 454 in the truck. It is supposed to be running well, good oil pressure and the like it just has a bottom end noise as per the owner. I have not heard it but I don't doubt it.

I could rebuild the 454 that is in it and run it as is but the truck would be down waiting on machine shop to get it all back to me. Then reassemble and install. I want to drive the thing NOW DAMNIT!... My thinking was to use the one I have that I know is a great engine, rebuild the one in the truck and use it on my project truck.

The Crewcab I am looking at is EXTREMELY MINTY NICE....it looks like a time capsule on the inside. Factory AC is blowing cold and all the bells and whistles. I want it to go back together quickly and a motor change is not even a weekend project for me. Versus at least a couple weeks to get the block back from the machine shop much less having the heads done.

 

[454Sub]

This is just my peespers experience. Not saying it's great, the best, or right even. But for me personally did work good enough. I don't have to pass emissions.

I run a Vortec era (96-00) 454 with TBI. It's a simple setup. I milled and smoothed the heads and chambers, added a high rise dual plane carb intake without an EGR spot. Added an adapter and bolted my ported 454 TBI unit on it. Running the stock cam. I am just running a stock 454 ecm chip for a manual transmission. (My 80e is full manual) and as of right now the speed sensor isn't working. Anyways it runs fine. Is it perfect? No, but it runs day in and day out, never throws a CEL, and always starts. I did a very very simple tune on it. TBI engines just basically dump all the fuel at WOT, so I raised pressure and read my scanner and guessed fuel pressure till i got an average of .600-800 ohms on the O2 sensor reading. Now this is incredibly backwoods way of doing it. The ohms bounce around terribly with a narrow band but it can be close "ish". But multiple full throttle blasts have been run with plugs being checked and they look good on mine. So it's close enough.

It's far from ideal, but for my particular setup it works great. If the cam is mild it will be fine. Port the TBI as best you can, and add an adjustable fuel pressure regulator and tune as best you can and have a chip burnt whenever.


And this is kind of garbled but I'm balancing this and some new show on tv.

And 13.5 psi on my liquid filled gauge is what mine runs.

 

[Vombrown]

This is just my peespers experience. Not saying it's great, the best, or right even. But for me personally did work good enough. I don't have to pass emissions.

I run a Vortec era (96-00) 454 with TBI. It's a simple setup. I milled and smoothed the heads and chambers, added a high rise dual plane carb intake without an EGR spot. Added an adapter and bolted my ported 454 TBI unit on it. Running the stock cam. I am just running a stock 454 ecm chip for a manual transmission. (My 80e is full manual) and as of right now the speed sensor isn't working. Anyways it runs fine. Is it perfect? No, but it runs day in and day out, never throws a CEL, and always starts. I did a very very simple tune on it. TBI engines just basically dump all the fuel at WOT, so I raised pressure and read my scanner and guessed fuel pressure till i got an average of .600-800 ohms on the O2 sensor reading. Now this is incredibly backwoods way of doing it. The ohms bounce around terribly with a narrow band but it can be close "ish". But multiple full throttle blasts have been run with plugs being checked and they look good on mine. So it's close enough.

It's far from ideal, but for my particular setup it works great. If the cam is mild it will be fine. Port the TBI as best you can, and add an adjustable fuel pressure regulator and tune as best you can and have a chip burnt whenever.


And this is kind of garbled but I'm balancing this and some new show on tv.

And 13.5 psi on my liquid filled gauge is what mine runs.

Where did you end up with the fuel pressure?

 

[454Sub]

I edited my comment. 13.5 is what I ended up with.

 

[dyeager535]

...I raised pressure and read my scanner and guessed fuel pressure till i got an average of .600-800 ohms on the O2 sensor reading. Now this is incredibly backwoods way of doing it. The ohms bounce around terribly with a narrow band but it can be close "ish". But multiple full throttle blasts have been run with plugs being checked and they look good on mine. So it's close enough.

It's how I do my setup as well, because I don't have a wideband, I don't think it's "wrong" more than it's right lol. As long as it doesn't run lean under the most demanding engine conditions, it's probably good enough. But you took the time to check that out, which many people don't. It will feel fine under load running lean (which is why some people say "but mine runs fine and I did XYZ and didn't tune it!) however until you check the mixture, you run the very real risk of detonating and/or melting the pistons.

In the 454 I mentioned in my dads truck, it needed a bump of almost 20% to get fuel where it needed to be. The brand new stock TBI fuel pumps maxed out at 14PSI, and it could have used a bit more pressure to get the injector duty cycle down a bit and leave a bit of a margin for more engine load. But without buying new (again) EP381 fuel pumps, and figuring out the switching valve issues with high pressure, we left it alone after tuning it via chip as best we could with the lackluster fuel pressure. I'm pretty sure that truck/TBI engine was used multiple times to tow a 10,000 pound travel trailer over the mountain pass.

 

[454Sub]

Mines running a Walbro 250 if memory serves.

I did three basic tests involving plugs. Idle, 3000 and 6000 rpms. Each showed a decent color.

The factory O2 is a narrow band sensor. With the scanner you can semi accurately read milivolts which translates to air/fuel roughly. Especially compared to a wide band. But anyways it did work, and it's ran for years happily enough. I felt super shade tree brilliant when I did it 10+ years ago before I understood efi related tuning. Haven't changed it since.