Author Topic: Engine swap...4.3 to 5.7  (Read 7252 times)

Offline dirtracer81_2

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Engine swap...4.3 to 5.7
« on: November 24, 2009, 08:26:22 pm »
Ok I took out the old 4.3 out of the 86 and now the 350 is ready to go in I thought....I had always heard they use the same motor mounts but after looking im wrong. My frame has multiple holes drilled factory I do beleive.

*My question is do I need to find the mounts from a truck with a 350 and use them?

*Also the power steering lines will they also work on the 350 pump?

Thanks

Offline zieg85

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Re: Engine swap...4.3 to 5.7
« Reply #1 on: November 24, 2009, 09:49:11 pm »
Do a search, you will see the differences.  In short you will need the V-8 setup for your truck.  2wd is different that 4wd.  The power steering hoses are much longer with the V-6. 
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
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Offline frito-bandito

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Re: Engine swap...4.3 to 5.7
« Reply #2 on: February 04, 2010, 07:57:02 am »
You need to be sure and get 350 mounts.
1981 Chevy dually 350 4spd. (One piece at a time)
1994 GMC C1500 4.3L 4L60E. (340K Daily Driver/Resto-Mod)
1998 GMC C1500 5.0L 4L60E (179K Daily Driver)

Offline jaredts

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Re: Engine swap...4.3 to 5.7
« Reply #3 on: February 04, 2010, 08:07:33 am »
Wouldn't the mounts from any sbc work?  It wouldn't have to be a 350 would it?  I just bring that up because 305's might be more common in the junk yards.

Offline murraygmc

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Re: Engine swap...4.3 to 5.7
« Reply #4 on: February 04, 2010, 08:18:29 am »
yes, i did the same thing to my truck . the mounts on the frame are different . you need the ( frame mounts off a truck that had a 350 ) if i remember correctly  you mounts are about 2 1/2 - 3 inches  from the crossmember the ones you need mount against the crossmember ..... watch your fingers them bolts can b knuckle busters and a real sob.... good luck and have fun!!!!
85 gmc high serria 4x4

Offline Captkaos

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Re: Engine swap...4.3 to 5.7
« Reply #5 on: February 04, 2010, 09:31:00 am »
All V8 mounts are the same so yes you need V8 mounts, 305, 307 350, 400, doesn't matter as long as it comes out of a 73-87 truck.

Offline murraygmc

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Re: Engine swap...4.3 to 5.7
« Reply #6 on: February 04, 2010, 09:54:12 am »
right because i went from the 4 cyl to a 305
85 gmc high serria 4x4

Offline Captkaos

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Re: Engine swap...4.3 to 5.7
« Reply #7 on: February 04, 2010, 10:08:57 am »
You did that in a fullsize murray?

Offline murraygmc

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Re: Engine swap...4.3 to 5.7
« Reply #8 on: February 04, 2010, 10:30:19 am »
O sorry , i meant to type i put a v8 in my 85 full size 4x4, went from the 4.3 to a 305 ..... sorry about the confusion
85 gmc high serria 4x4

Offline frito-bandito

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Re: Engine swap...4.3 to 5.7
« Reply #9 on: February 21, 2010, 07:22:35 pm »
Wouldn't the mounts from any sbc work?  It wouldn't have to be a 350 would it?  I just bring that up because 305's might be more common in the junk yards.

Yes as Capt. Said, any mounts from a V8 equipped 73-87 truck will work, sorry if I was misleading.
1981 Chevy dually 350 4spd. (One piece at a time)
1994 GMC C1500 4.3L 4L60E. (340K Daily Driver/Resto-Mod)
1998 GMC C1500 5.0L 4L60E (179K Daily Driver)