TBI 350 to TBI 454 swap?

[24 Karat Brown]

I'm getting bored of the ole TBI 350 and looking into swapping. How plug and play is a TBI 454 to swap in? I also have a NV3500 trans which I dont expect to last but a few years. At first I will drop the motor in bone stock and work out any issues until it works as if it was meant to be. THEN I'll do performance. My truck is a 94 C1500 RCSB with the TBI 350 and NV3500 5-speed. I will also have to eventually swap the trans to a NV4500, but will the 3500 bolt on to the 454?

 

[b454rat]

Bell will bolt up no problem. It’s been awhile since I looks into this swap but believe IAC n TPS plugs were different, and of course the prom....

 

[Cale N]

I did a V6 to a 350 swap so I'd say you would have a similar experience to me. Just need to make sure you are able to find the PROM chip from a 454 truck and you will have to get bigger injectors on the TBI unit and I'm not sure but the big block might have different motor mounts.

 

[PlayingWithTBI]

you will have to get bigger injectors on the TBI unit

You'll have to get the Throttle Body for a 454 since it's 50mm bore while the 350 is 42mm. The injectors for 88-90 7.4L are 80PPH, and 91-93 are 74PPH, while 94-95 are 46PPH @ 13PSI but they were run @ 26-32PSI for 67-72PPH. The stock 5.7L injectors are 61PPH, while the Cop Car ones are 65PPH.

So, you'll have to match your injectors' year to the same year PROM or, tune it.

EDIT: BTW I stole this data with pride from EagleMark on GearHead-EFI.com

 

[LC2NLS6]

I've had 2 TBI 454s. Both are dog slow stock. Best bet is LS swap it. Cammed and tuned 5.3 LS will out perform a TBI Gen V 454 L19 cammed, tuned w/ exhaust and intake upgrades, I know, I have both and the 5.3 Suburban is quicker.

 

[b454rat]

I had 2 TBI 454 trucks, one with 35s and 3.42s, the other with 40" boggers and 3.73s. BOTH would lite the tires up. Not at a stand still, but slight turn on take off. Both were stock rebuilds. Torque rules, something an LS can't say lol

 

[badco]

396 closed chamber heads on a tbi 454 picks them way way up on tq and hp

 

[DerekTheGreat]

I had 2 TBI 454 trucks, one with 35s and 3.42s, the other with 40" boggers and 3.73s. BOTH would lite the tires up. Not at a stand still, but slight turn on take off. Both were stock rebuilds. Torque rules, something an LS can't say lol

We had one '88 TBI 454 truck, C3500. It would light the tire up and throw you back in the seat in 1st if you punched it. Well, you'd get thrown in the seat if the tire didn't break loose. But you could put that SM465 in direct drive (3rd) at about 12mph and it didn't sweat, would just comfortably burp it's way to whatever top speed you felt like. I never felt comfortable CRUISING at anything higher than 60.

Our 350 TBI trucks seem just as fast but do not have the grunt the 454 had, so you're not dropping them into direct at 12, more like 20. If you give it anything more than toe in at that point, lug. They're also some 100 - 115% better on gas though. Best I ever managed with the 454 was 7.5ish MPG and 17.xx with my K1500. I miss that 454 but with all things considered, I don't need it. Would I love to have one as a spare vehicle? Oh yeah. Fat f'n chance finding another regular cab, long box single rear wheeled stickshift version though.

 

[geeeee89]

I've had 2 TBI 454s. Both are dog slow stock. Best bet is LS swap it. Cammed and tuned 5.3 LS will out perform a TBI Gen V 454 L19 cammed, tuned w/ exhaust and intake upgrades, I know, I have both and the 5.3 Suburban is quicker.

this has zero to do with what he asked about. not everyone wants to LS swap.

We had one '88 TBI 454 truck, C3500. It would light the tire up and throw you back in the seat in 1st if you punched it. Well, you'd get thrown in the seat if the tire didn't break loose. But you could put that SM465 in direct drive (3rd) at about 12mph and it didn't sweat, would just comfortably burp it's way to whatever top speed you felt like. I never felt comfortable CRUISING at anything higher than 60.

Our 350 TBI trucks seem just as fast but do not have the grunt the 454 had, so you're not dropping them into direct at 12, more like 20. If you give it anything more than toe in at that point, lug. They're also some 100 - 115% better on gas though. Best I ever managed with the 454 was 7.5ish MPG and 17.xx with my K1500. I miss that 454 but with all things considered, I don't need it. Would I love to have one as a spare vehicle? Oh yeah. Fat f'n chance finding another regular cab, long box single rear wheeled stickshift version though.

I just recently picked up a 89 C3500 reg cab long bed auto with a 454. I always heard the motors were slugs but I think that's exaggerated. Mine will definitely light up the tires and put you back in the seat. I agree with you though on the mileage. My K1500 is my daily driver - I only got the C3500 as a spare truck to pull a trailer with. I'm casually on the lookout for a 2wd NV4500 as a swap for later

 

[DerekTheGreat]

In the year and some change we owned our 454 truck, I never came across an affordable NV4500. That's ultimately why we sold it. Hopefully you have better luck.