4.3 to 5.7 engine swap

[jays2w87]

Has anyone out there swapped out a 4.3 (v6) TBI and put in a 5.7 Carb engine ? My new resto / mod truck is a 87 1500 long bed. I have done a few trucks (5) and this one is the 1st with out the small block already in it. So, since the truck is in Great shape and I LOVE this truck I wanna put a v8 in. I know there are many out there that would rather the TBI or TPI engine for this rig but, I'm alittle old school and I really  wanna get back in touch with a carb engine. 
Some of my issues might be..... engine mounts ?? anyone. (I have not yet popped out the 4.3 to get a good view) Or how about fuel ? I can clip my in tank pump wires and plug the supply and run fuel to the mechanical pump via the return I have now, ... right ?

[Captkaos]

You won't be able to pull fuel through the EFI pump with a mechanical one, and I wouldn't recommend using the return line. 
The 4.3L is the same as a V8 350, just 2 cylinders are missing.  Everything will actually swap right over including the TBI unit, you just need an intake, different injectors and a new chip and you are ready to go... It would be MUCH easier staying with the TBI.

Personally if I were to go the Carb route I would replace the sending unit with a Carb version and run the supply to the current supply and tie into the existing fuel line.

[zieg85]

Some of my issues might be..... engine mounts ?? anyone. (I have not yet popped out the 4.3 to get a good view) Or how about fuel ? I can clip my in tank pump wires and plug the supply and run fuel to the mechanical pump via the return I have now, ... right ?
[/quote]

I am about to do that swap.  Looks to me that the frame mounts are different but I have had a chance to take it out yet.

[jays2w87]

I know that in my past mods I have seen the kits, s-10, ranger and so on, I have not see a chevy (GM) swap kit out there. Thats not to say there is not one, I never assume.....
I have looked at the small block mounts and the 4.3 mounts . They are different. However they are only off by 1/2 inch (it looks) block plates that is. I'm hoping the frame mounts in the truck are suitable to take the small block.... You would think they did not differ that much. That would cause too much confusion on the assembly line (so you'd think) 
Knowing that the tbi set up is still on the drawing board makes me feel better.
Is the fuel pressure the same for both 6 and 8cyl set ups? Or would the size injector I use determine that?   
     fyi (this forum is awesome !!!!!) 

[Captkaos]

S10s never came with a V8, that is why there are swap kits in them.  The C10's did and that is why there isn't one for them.
The frame mounts are the same, the block clamshells are not the same, you need the V8 mounts.  All the accessories will bolt to the 350.  You need a different radiator and a shroud, intake and 350 injectors, and the exhaust MAY have different outlets.  (off the top of my head)
All TBI systems us the same pump an all use the same Throttle body, the only difference is the injector size (this excludes the 454 TB)

[jays2w87]

Okay, Sounds good. I think tbi is the way .....
Thanks for the info !

[VileZambonie]

TBI is definitely the way to go 4 your truck. BTW You're very close to me in Enfield. If you need anything let me know.

[Bitzer!]

You're very close to me in Enfield. If you need anything let me know.

wish i was state side 

[jays2w87]

Sweet ! Good to know, I think I'm gunna start cleaning out my garage. This project is going to run into the winter so thank God for heated garages !
I'm still lookin for an engine. Currently the 4.3 is shot. I though about workin on it to make it drivable till I do the swap, but I dont wanna spend money on a engine I dont want. I'll keep you posted.
Like wise on the help. I'm either at work or home (3 kids) so let me know!

[1973c20]

rather than putting the V6 back in, just cut a hole in the floor and do like the Flinstones!

[jays2w87]

yah, not a huge 6 cyl fan..... If were talkin about my daily driver ya sure. Although I thought about lookin for a wrecked Buick GN . I have seen a few my some crazy power at the Track. Built and geared runnin mid 9.'s   Or all that and juice gettin into low 9's high 8's
Only issue is finding a GN engine is not easy.

This time I'm doin a streetable truck. Something I can drive to work all summer, that looks good and can burn the tires whenever I feel the need. When I have a ride that hooks up nice I dont mind buyin tires once a year ......... (some times twice)

[jays2w87]

Hey Bitzer
My buddy lives over there in Enfield. I've know him my whole life. Great guy ..... owns a 89 Suburban and a 76 step side Runs 38 inch tires. The pick up is Black and the sub is Blue. 
Says Tattooed white trash on the tail gate.Really sweet rig. 
He also had a Jeep Cherokee set up really nice. died though so you wont see that one around Enfield anymore.

[zieg85]

If I could find a good used 4.3 for my 86 I would put one back in it.  They are good smooth running and get decent fuel economy.  I just can't find one around the Chicagoland that is any good.

[jays2w87]

Dont get me wrong they ARE a great engine. Again I drive one to work and back everyday! However for a custom resto / mod I think the way to go is 8 cyl. The power, look, sound. You cant beat it !
The 87 I have has 80,000 miles on it so I think I might actually rebuild this 4.3 and wrap it in plastic.
You never know........

[zieg85]

My 86 has a little less that 71K on it and it goes through about a quart every 200 miles.  She sat for a while and I think the oil rings went bad, i bought it that way.  I have to push start it because the block is cracked where the starter mounts so the block is junk.  Everything else is good including the carb and all the emission stuff which I need.  I know there are a lot of 4.3L out there but I need one that I can put the mechanical fuel pump on so my years are limited.