The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 05-20-2012, 08:26 PM   #1
buffle
buffle
 
buffle's Avatar
 
Join Date: Sep 2004
Location: Independence, Mo
Posts: 431
Question V/6 to V/8

I just bought a 1987 FI V/6 truck. Will it be a nightmare to V/8 it. It has a 400 turbo in it now.
__________________
Life is like a roll of toilet paper. The older it is, the faster it is used up.
buffle is offline   Reply With Quote
Old 05-20-2012, 08:55 PM   #2
86c20
Registered User
 
86c20's Avatar
 
Join Date: Mar 2012
Location: edgartown mass
Posts: 853
Re: V/6 to V/8

i dont see why it would be. you would need the v8 cpu and the correct throttle body for a v8. if it has a 400 you are fine. but i think wwe need more info here. what v8? 305 350 454? i do know one thing for sure you will need a bigger rad unless its a 305. imho a 305 is a wast of time. also if there is no emissions in your area you could just but a carb on it and call it a day.
86c20 is offline   Reply With Quote
Old 05-21-2012, 01:38 AM   #3
andrewmp6
Registered User
 
Join Date: Jan 2009
Location: Louisville,Ky
Posts: 5,817
Re: V/6 to V/8

If it was me i would go 350 and a over drive trans like a 700r4 or maybe the 2004r which is what the g body had.Or if you got the cash a ls1 4l60 is a nice combo too.
andrewmp6 is offline   Reply With Quote
Old 05-23-2012, 02:47 PM   #4
remist17
Registered User
 
remist17's Avatar
 
Join Date: Jul 2009
Location: PA
Posts: 406
Re: V/6 to V/8

I just completed a 87 V6 to a 383. I also have the 400 trans option.

The motor mounts can be a pain in the butt. The V6 will not work on the V8 model. Also note that just any V8 motor mount bracket will not work on the truck or at least it didnt on mine.

If your going carb then the CPU is not needed, but since 87 was the first year to have teh 400 kick down in the computer a switch is needed. Bought it have not installed it yet.
__________________
2013 Chevy Silverado, Z71, 5.3L, 4 door
2005 Chevy Silverado, Z71, 5.3L, 4 door, 3.40

Support the Troops.
remist17 is offline   Reply With Quote
Old 06-17-2012, 10:55 PM   #5
x ReAcT x
Registered User
 
Join Date: Apr 2012
Location: Virginia Beach, Virginia
Posts: 219
Re: V/6 to V/8

Quote:
Originally Posted by remist17 View Post
I just completed a 87 V6 to a 383. I also have the 400 trans option.

The motor mounts can be a pain in the butt. The V6 will not work on the V8 model. Also note that just any V8 motor mount bracket will not work on the truck or at least it didnt on mine.

If your going carb then the CPU is not needed, but since 87 was the first year to have teh 400 kick down in the computer a switch is needed. Bought it have not installed it yet.
Im about to convert an 86 v6 to a RAMJET 350 v8, from what it sounds like, the motor mounts are going to be a huge problem, is that true?
__________________
1986 GMC K15 4.3V6/SM465/NP205
will be converting to
5.3LS E-ROD/AA adapter/SM465/NP205

10 Bolt Axle Rebuild Tutorial:
http://67-72chevytrucks.com/vboard/s...d.php?t=536415
x ReAcT x is offline   Reply With Quote
Old 06-18-2012, 12:00 PM   #6
rollinhard
Registered User
 
rollinhard's Avatar
 
Join Date: Jun 2010
Location: British Columbia
Posts: 192
Re: V/6 to V/8

In 87 the trans was changed to a 3L80hd essentially a t400 with long 28 spline output shaft. Just an fyi. And the motor mounts arnt a big issue. You can use the ones off the v6 but have to adjust them as far as I can remember. Did this swap many years ago. But I went carb'd.
Curtis
__________________
If you can't impress them with your inteligence, dazzle'm with your stupidity

1969 GMC lwb 2wheel drive can you say big stroker motor to come hehe
rollinhard is offline   Reply With Quote
Old 06-18-2012, 08:10 PM   #7
Chevylongbed
Registered User
 
Join Date: May 2012
Location: Vienna, VA.
Posts: 37
Re: V/6 to V/8

Quote:
Originally Posted by 86c20 View Post
i dont see why it would be. you would need the v8 cpu and the correct throttle body for a v8. if it has a 400 you are fine. but i think wwe need more info here. what v8? 305 350 454? i do know one thing for sure you will need a bigger rad unless its a 305. imho a 305 is a wast of time. also if there is no emissions in your area you could just but a carb on it and call it a day.
How about if i want to have 454 engine, what should i change?? and what is the best manual tranny for it??
__________________
1987 Chevy C20 LWB Stepside
2009 Mercedes-Benz C63 ///AMG
2013 Lexus LX570
Chevylongbed is offline   Reply With Quote
Old 06-18-2012, 10:13 PM   #8
rollinhard
Registered User
 
rollinhard's Avatar
 
Join Date: Jun 2010
Location: British Columbia
Posts: 192
Re: V/6 to V/8

What r your plans for the truck and that would determine quite abit.
__________________
If you can't impress them with your inteligence, dazzle'm with your stupidity

1969 GMC lwb 2wheel drive can you say big stroker motor to come hehe
rollinhard is offline   Reply With Quote
Old 06-20-2012, 02:57 PM   #9
remist17
Registered User
 
remist17's Avatar
 
Join Date: Jul 2009
Location: PA
Posts: 406
Re: V/6 to V/8

Quote:
Originally Posted by rollinhard View Post
In 87 the trans was changed to a 3L80hd essentially a t400 with long 28 spline output shaft. Just an fyi. And the motor mounts arnt a big issue. You can use the ones off the v6 but have to adjust them as far as I can remember. Did this swap many years ago. But I went carb'd.
Curtis

This maybe true on most trucks. The one I have the 6 cyl mounts will not work. These are not the same as the 8 cyl and unless you want yo do some fabrication to make these work it is easier to find the entire set up in a junk yard.

Take measurmenets of the frame as these are also different from model to model. Again this is from my experience and headaches. If you want more informtion on what I went through PM me.
__________________
2013 Chevy Silverado, Z71, 5.3L, 4 door
2005 Chevy Silverado, Z71, 5.3L, 4 door, 3.40

Support the Troops.
remist17 is offline   Reply With Quote
Old 06-20-2012, 06:14 PM   #10
rollinhard
Registered User
 
rollinhard's Avatar
 
Join Date: Jun 2010
Location: British Columbia
Posts: 192
Re: V/6 to V/8

Ya your right. I looked in lmc and it shows small blocks from 73-87 are the same. V6 are 2 different part #s and I6. Is the same as small block. Then big block is different again.
__________________
If you can't impress them with your inteligence, dazzle'm with your stupidity

1969 GMC lwb 2wheel drive can you say big stroker motor to come hehe
rollinhard is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 01:41 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
Copyright 1997-2013 67-72chevytrucks.com