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Thinking about a v8 swap 90 astro but have ??

9K views 39 replies 7 participants last post by  Bertscova 
#1 ·
First will the orig ac and all the pullys on the front of my 4.3 bolt onto a 350 of the same year ?
Can I use my tranny ? Its a 700r4 with about 2500 miles on it bought new from gm goodwrench.
I know almost nothing about tbi so would use an hei dist and prob a small vac secondary holly carb.
I'm still on the fence about doing a swap cause i need more info on how easy it can be done.
I do have to change the engine cause the orig engine was overheated and now spray the water
out the tailpipe as fast as i can put it in the radiator Ya it still runs like that.
So any comments or suggestions would be great
 
#2 ·
stick with the TBI and same year v8 everything should bolt right up, I went am in the process of doing a carb and am second guessing my decision of it would be easier, too many wires to mess with...wont do it again! there are several issues that have to be delt with that I came across so far when you go carbed due to eliminating the ecm.
1) dist you have to run an ignition wire. easy enough...
2) fuel pump working on this one....
3) tourque converter lockup switch....
anything else I come across I'll let you know.
my advice would be get a V8 TBI motor and stick with it...
 
#3 ·
Could you plse tell us if you have a AWD or RWD van.That will make a difference on a V8 swap.You can use your current tranny,but I would suggest you install a trans-go kit,vett servo, and a .5 boost valve with a tranny cooler.Depends on your state reg's for smog testing which engine to install and what type of fuel system.(carb vs TBI)Example is as I understand Calli smog rules,you need a engine the same yr or better with all the smog senors connected and working correctly.(check your area reg's)The carbed V8 swap is likely the most simple,but the TBI's aren't that hard.I have seen threads where the V8's will start off the computers of the 4.3's,but not run that good.Chip burns are not that expensive and may take acouple of trys to get right.The fuel pump you have will support a TBI 350 and will need a reg for a carb app.Depends on if you have a AWD or RWD on which motor mounts you going to need to build or buy.The oil pan is also depending on RWD or AWD.A lift is also helpful when doing a V8 swap to make getting to spark plugs easier to get to.(you don't need to go nuts with that,even a 2" lift helps.)TBI's will give you faster starts and alittle better gas mileage.Look for a donor engine from a 1990 to 1994 truck TBI.A good manuel to do a search for is at is link:WWW.JTRpublishing.com

Chops,and others have built engine mounts and you will see in the back of that manuel a diagram how to build your own too.

For me,I short-cut alot of that because I bought a Astro that had a Vortec engine already installed in it.I am using that as a donor van for the project that I am doing.

Is a V8 swap worth it?????.Yes,Yes,Yes-for sure.Just continue to ask questions at each stage of it and there are all kinds of people to help.Spend the time to research all the info you can.I waited for almost two yrs before I made a move,but that is just me I guess.LOL

Gar
 
#4 ·
Thanks for the info Its a RWD. If I buy motor mounts will the have the lift you talk about ? Also will a v8 emc plug into the existing harnes ? So it sounds like you just plug and play. How about the front springs is there much difference in weight between the 8 and 6 ?
 
#5 ·
Bertscova said:
Thanks for the info Its a RWD. If I buy motor mounts will the have the lift you talk about ? Also will a v8 emc plug into the existing harnes ? So it sounds like you just plug and play. How about the front springs is there much difference in weight between the 8 and 6 ?
The lift is done via spacers betwwen the sub frame and the Astro.Extend some wires.The front springs are fine with the V8.You could get heavy duty front springs for a lift,but the key is to lower the sub frame to get better access to the engine.Of course you lift the rear the same amount as the front.Having a RWD make it simple.This is one of the easiest swaps around.Better power band than the V6 and more towing ablility.As I said,it is worth doing for sure.Just got to remember these vans are normally very heavy and don't have any areo of any kind.Torque is the key with them at a lower rpm.
 
#6 ·
Thank you for the info. A couple more questions, Does anyone have a list of parts i will need to buy and where i might buy them. THANKS AND KEEP THE COMMENTS COMMING
 
#8 ·
ok you DO NOT have to do a lift to do a V8 swap it will fit with out it. I do have the list just gotta find what I did with it. You only use the prom chip from the V8 ecm in your current ecm. you need to use the V8 injectors in your v6 TBI dont bother with that manual its a waste of money I could scan the astro section for you. as far as carburated I advise against it you will get alot more help, advice and answers faster going with a tbi setup I have been fiddeling with wires for a minute and now im bald!lol. Everything I have read about v8 swaps says about the same thing stick with the same year and you'll be fine dont let some people make it sound more complicated than it really is, its a peice of cake in all actuallity...





and this is what they look like for a rwd

 
#9 ·
Thanks Chops those mounts look easy to make got a buddy who can make them for me he has a metal shop in his garage. do i have to use headers ? from what i can remember correctly don't headers make it harder to change the plugs. if i use the v8 cast manifolds will they bolt up to the orig exhaust ? O yea if you can find that parts list Chops that would be great. Keep the comments and suggestions comming. thanks to all
 
#13 ·
chops said:
ok you DO NOT have to do a lift to do a V8 swap it will fit with out it. I do have the list just gotta find what I did with it. You only use the prom chip from the V8 ecm in your current ecm. you need to use the V8 injectors in your v6 TBI dont bother with that manual its a waste of money I could scan the astro section for you. as far as carburated I advise against it you will get alot more help, advice and answers faster going with a tbi setup I have been fiddeling with wires for a minute and now im bald!lol. Everything I have read about v8 swaps says about the same thing stick with the same year and you'll be fine dont let some people make it sound more complicated than it really is, its a peice of cake in all actuallity...





and this is what they look like for a rwd

Chops is right about not needing a lift to make it fit.Just ya know it does make it tons easier to get to things if ya do_Of course chip burns are not needed if you keep her stock and you can transfer them.(But not many do that,keep it stock,hehe)I have a set of RWD mounts and if I don't end up using them because there is a set in the donor van,I will sell them to you for what I paid for them with the manuel that I spoke about.I got them from my bud Chops and we both agreed that I would pass the favor on if I could.Chops-send a PM to me because I honestly don't remember how much that was.State smog Reg's and knowing what they want(or how to get around them),is a safe way to build one of these V8 vans.Each state is alittle different.That way you can include that in the swap planning.Not complicated at all,just the safer route to have that in hand.As both Chops and I have posted,these swaps are one of the easiest ones around.

Keep us posted on your progress,

:banana: :layrubber:

Gar
 
#14 ·
Thank for all the suggestions i'm gonna do the v8 swap will post pic of the progress along with anything information that i come across that might be helpful for others. Please keep the suggestions comming, you can never have to much information.
This is the first Rear Wheel Drive van that i've owned and i love it, looked for a while for a short wheel base astro. Bought this one about a year ago from a couple that had to be a least 200 years old. They bought it new in 1990. They had every reciept for all the work ever done on it along with a print out from the dealership for all oil changes and service done dating back to the day they bought it. The tranny had been replaced only 150 miles before i bought it. With a brand new not used tranny from gm goodwrench. Also they had the entire ac system replaced about a year before i bought it, again with all new not rebuilt parts. It also had 4 brand new goodyear eagle gt tires that still had the rubber casting nobbies. I payed $2400. for it
I Think i got a great deal. Until i loned it to a friend and he drove it without water until it died :cussing: needless to say i will never lone out any of my vehicles to anyone for any reason . Once again thank for the sug. and keep them comming.

P.S.
Anyone wanting an overheated 4.3 with 189,000 mile to rebuild they can have this one FREE of charged I live in florida so just pay for shipping let me know how to package it and when they will be here to pick it up.

Bert
 
#15 ·
Ok one more question If i get a 5.7 tbi out of a 1990 chevy truck and have them leave the engine wiring harnes attached to everything will the 8 cyl harness plug into the vans engine wiring harnes socket.
Sorry for all the questions but the only dumb question is the one not asked
 
#16 ·
that I reall do no know personally but the harness from the astro will fit everything on that 5.7 you may need to extend a few lines so doesnt hurt to get the harness so you can use the wire atleast.
 
#17 ·
We are going to find out. cleaning out my garage this weekend to make room, Then next weekend start of the project. Will post pics for chops i read on another thread that chops likes pics :pics:
 
#19 ·
I was once told "
" when I first joined because I was talking about what I was doing and didnt post any pics (Gary knows this feeling to) so know I make sure I take pics. now if I only wasnt lazy I would actually post em but I do LOVE pics thats where we get our Ideas.
 
#20 ·
I was just out looking at the van and was wondering will the ac hoses bolt back up or do i need to exstend any of them. I noticed that all of you guys are way north of me. Here in florida i have to have ac because 7 months out of the year it between 90 and 100 degrees here.

Are any of you comming to florida next weekend I'll by the beer :bigsmile:
 
#21 ·
I dont believe you do! due to the fact out of all the guys who have done the v8 swap and still have ac have never mentioned extending or replacing just a mental note for you there are somethings you may have to bend or tweak (such as mounting brackets) as you go but not many!
 
#22 ·
chops said:
I dont believe you do! due to the fact out of all the guys who have done the v8 swap and still have ac have never mentioned extending or replacing just a mental note for you there are somethings you may have to bend or tweak (such as mounting brackets) as you go but not many!
My donor V8 Astro van has the A/C jook up.Honestly I haven't looked at that part of it yet.I'll let ya know what I see next time I go to work on it where it is parked at a reapir shop.
 
#23 ·
Started the swap today and was reminded that i have front and rear ac . So I think i need to make the alum line comming of the rear of the compressor alittle longer. Is there a easy way to do this or should i give up the rear ac and get a new ac line from a van with just front ac. also my compressor is on the drivers side. what side is the compressor on in single ac vans. :confused1:
 
#24 ·
Ok I answered my own question but thought i would leave it posted along with this answer for other members to read

On my van with rear ac the top hose in the pic is all alum and runs across the top of the drivers side valve cover and L's down
at the back where it connects to the hose that goes to the rear system. The hose that goes to the dryer is T'd into the other hose (not the way in pic)This is a replacement assembly from a local parts store. All i have to do is to replace the top hose with a longer one. Solved the prob and answered my question
Here is a pic of the van before engine death :cussing:


Im going to have an emblem made like this. I went to a website that had pics of emblems and used Photshop CS2
To edit and make what i think would be an aswome emblem Ill let people know who i Have make it so if they want
some the can get a pair
 
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