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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: hdloner on March 07, 2008, 04:35:12 am

Title: motor swap
Post by: hdloner on March 07, 2008, 04:35:12 am
have a good strong buick 1986 307 carb motor   i want to put it in my 1986 c20 350  turbo 350 trans what problems will i run into
Title: Re: motor swap
Post by: VileZambonie on March 07, 2008, 04:44:19 am
The 307 was a total loaf. I think they had 7.5:1 compression ratio. Why would you put that in place of your 350?
Title: Re: motor swap
Post by: Blazin on March 07, 2008, 06:09:30 am
I agree I would opt for a half worn out 350 over a strong running BOP 307.
Title: Re: motor swap
Post by: hdloner on March 07, 2008, 07:23:56 am
350 has 278000 miles 307 has 10000 and is paid for
Title: Re: motor swap
Post by: HAULIN IT on March 07, 2008, 08:51:57 am
Hdloner, I pretty much agree with the other guys, however the 307 Olds (not Buick, it may have been in a Buick,but it's an Olds ???) for the most part, is a good longevity engine, not the best choice for a truck necessarily though. Since you asked, the basics are this. You will need Olds-based diesel mounts (mid-late '70's) or make adapters like I did (a plate across the three bosses on the block w/studs) or move the lower half on the frame plate (I did my 4x4 this way). A transmission adapter (Trans-Dapt, makes two, the 3/8" thick one is the one you want), the battery should be moved to the Left side. The accessories will interchange, you will need to lengthen a few wires,hoses,ect. The exhaust will work out fairly well, as well as the fan shroud,ect. also. It is a do-able weekend swap if well prepared, but I don't think I'd bother, now a 350-455 :) :)  Lorne(http://i163.photobucket.com/albums/t285/HAULINIT/100_0127.jpg)
(http://i163.photobucket.com/albums/t285/HAULINIT/100_0118-1.jpg)
Title: Re: motor swap
Post by: Stewart G Griffin on March 07, 2008, 06:35:23 pm
This, in my opinion, will be a cool swap.  Even though i'm a "chevy person,"  i'm obsessed with anything GM. i'm a "GMphile."  i'm obssesed with B.O.P. (especially P) and Cad, and of course, GMC.  (Although, today's GM leaves a lot to be desired, but that's a topic of a whole other post....)

1) Anyways, i was wondering why the battery should be moved to the left side?


2) We have to remember that the last 442 had a 307 which pumped out 180horse and about 235lbs or torque.  Yes, i realize that the cutlass was about 1000lbs lighter than a fullsize truck, but still.

If the 350 is still running, i would wait until it needs a rebuild before swapping it out though.
Title: Re: motor swap
Post by: red4wd on March 07, 2008, 06:41:11 pm

1) Anyways, i was wondering why the battery should be moved to the left side?


because they have the starter on the left side of the engine
Title: Re: motor swap
Post by: plowking_90 on March 07, 2008, 06:48:30 pm
i had a olds 350 rocket in a truck before it was a good running motor but was gutless. my opinion i would find a chevy 350 and junk the 307 you would be better off with a strait 6 then the 307
Title: Re: motor swap
Post by: VileZambonie on March 07, 2008, 07:29:48 pm
My buddy has the original 307 we pulled out of his 84 Hurst Olds and he asked me what he should do with it. Now if he only had a boat... lol

The 307 is a pig, poor performance, poor mileage and is just a lousy choice for a swap even if you do already own it. You can freshen up your existing 350 to bring new life to it for probably around $400 bucks.