tbi350 to carbed 454 swap?

[88bigburb]

hello everybody,

i'm just starting out in the forum world, and i have a question of whether or not said swap is worth the effort, i spent several hours trying to find the exact answers already posted but i have this bad habit of getting sidetracked and wandering several pages deep into threads that are only loosely related, so i do apologize if this is already addressed in another thread, but thanks in advance for any advice/answers

Here's the details

Current:
88 v20 suburban
tbi350, th400, np208
10 bolt front, 14bff rear, 3.73 gears, locked rear
38.5" thornbirds
3inch body lift, 6 inch suspension

as u can probably deduce my suburban is severely underpowered,

the details on the proposed donor are sketchy at best for now, i haven't actually talked to the owner of it(friend of a friend), nor had a chance to look at the truck myself so I'll be as specific as possible
pricetag: $700
1977 chevy pickup (possibly 3/4 ton)
454 engine(presumably carbed)(2 or 4 barrel unknown)
no exhaust except manifolds to move over to suburban

so the questions are as follows

1. are there specific 454's that can or cannot use the stock tbi setup used in 87-91ish chevy's?
2. what additional parts would i have to acquire in order to make my current tbi setup work properly on a 454 as opposed to the 350
3. whether the 454 be left carbed or changed to tbi, what exhaust setup should i use(full dual, or single and size of pipe) exhaust will be custom, suburban is 8600 gvwr so no cats required
4. should i for-go engine swap, and somehow build my current engine?
5. or should i just work on obtaining a dana 60 front and regear the vehicle?

the main reason for the idea of a swap is because as best i can tell, 700 bucks for a fullsize pickup with a running 454 is a hell of a deal, again any advice will be greatly appreciated.

thanks a bunch,
Dom

Edit: just an afterthought, people have asked when i proposed this "what, dont ya spend enough on gas?" i get approx 6 mpg with the 350, so i figure my mileage really cant get all that much worse, so i might as well at least have some power, if u have any opinions that the 6 mpg is overly low, please tell me what may be causing it, lol thanks again

 

[4X4HIGH]

so the questions are as follows

1. are there specific 454's that can or cannot use the stock tbi setup used in 87-91ish chevy's?
2. what additional parts would i have to acquire in order to make my current tbi setup work properly on a 454 as opposed to the 350
3. whether the 454 be left carbed or changed to tbi, what exhaust setup should i use(full dual, or single and size of pipe) exhaust will be custom, suburban is 8600 gvwr so no cats required
4. should i for-go engine swap, and somehow build my current engine?
5. or should i just work on obtaining a dana 60 front and regear the vehicle?

Ok, let me start this off.

1) Pretty much any 454 can be converted to TBI as long as the cam is FI friendly.

2) You will need a TBI unit from a 454 (it's a larger CFM and larger injectors than one for a 4.3, 5.0, 5.7). You will need a IAC adapter harness, and depending on the year of TBI unit you find you might need a TPS adapter harness as well

3) I would run some form of headers and a single 3" exhaust will produce more low end torque than a dual exhaust.

4) I would check into the laws for engine swaps for your state to see what is/isn't legal the base your decision on those facts

5) Gearing goes a long way if everything else is good (engine runds good and no issues)

 

[tRustyK5]

hello everybody, <snip>

Here's the details

Current:
88 v20 suburban
tbi350, th400, np208
10 bolt front, 14bff rear, 3.73 gears, locked rear
38.5" thornbirds
3inch body lift, 6 inch suspension

as u can probably deduce my suburban is severely under geared,

Fixed.

You need deeper gears, without OD at least 4.10's, but I'd say 4.56's would be even better. The 6 mpg is most likely from that poor little TBI 350 having to work so hard at too low an rpm.

Rene

 

[88bigburb]

i went and talked to my mechanic today, he said as far as inspection, i can swap in whatever i want, but as far as emissions, it has to physically have everything it came from the factory with, and it has to appear to be in working condition, air pump, egr, and whatnot.

Mostly I'm hoping that when i actually get to see the truck its some sort of treasure trove of usable parts, as in th400 with a 205, at least 4'10's in the rear, and i dunno, some sorta tires or rims, lol.

but in any case, future plans for the vehicle are possibly drop the suspension to 4 inches, and up the tires to 42ish, with whatever necessary trimming, and working on scrounging parts to eventually go np203/205 doubler.

i have found a set of 1 tons with 4.10's, dude wants 400 for the front 250 for the rear, i'm thinkin as far that deal, drive an extra 45 mins and pick up a rear at harry's U-pull-it for like half the price, cuz i've seen plenty of 4.10 rears there. with the added bonus of a trip to harry's...

i really like junkyards....

another set about 3.5 hours away, 5.13's d60 front, with crossover arms, 14bff rear with spool, this dude wants 1500 tho,

so i dunno if 5.13's will be too deep or if they'll work allright with 38's and better with 42's but yeah i pretty much need deeper gears in any case.

thanks for the help so far and for any more u can provide