Author Topic: 1986 305 to 350 Vortec Swap  (Read 483 times)

Offline Jeff86inMS

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1986 305 to 350 Vortec Swap
« on: January 14, 2019, 02:51:28 PM »
Hello all,
I have a 1986 C10 stepside custom deluxe that originally came with a 305 V8.  I'm getting ready to swap it for a 350 Vortec V8 with Carb.  My question is, will the exhaust manifolds from the 305 swap over to the 350 Vortec?  I know the intake manifold is different.  Need to know about the exhaust ones though.  Thanks!

Jeff

Offline VileZambonie

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Re: 1986 305 to 350 Vortec Swap
« Reply #1 on: January 14, 2019, 04:40:32 PM »
Yes but why not run headers? Exhaust manifolds will choke that thing right out
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Offline Jeff86inMS

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Re: 1986 305 to 350 Vortec Swap
« Reply #2 on: January 14, 2019, 05:04:39 PM »
I will probably run headers later on, but trying to just stick to the items I have to have to get it installed.


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Offline Ronno6

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Re: 1986 305 to 350 Vortec Swap
« Reply #3 on: January 14, 2019, 10:24:52 PM »
Exhaust manifolds should oughta bolt right up.
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Offline JohnnyPopper

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Re: 1986 305 to 350 Vortec Swap
« Reply #4 on: January 15, 2019, 12:46:27 PM »
Unless you need a manifold spreader tool.

I just had my 350 swapped out, and the mechanic showed me a tool to spread the the outer manifold ports away from the center ports.

Wish I had known about them the last time I changed the manifold gaskets, would have been a lot less &&%$#(!!!@#^%$#!!????!!

Offline zieg85

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Re: 1986 305 to 350 Vortec Swap
« Reply #5 on: January 15, 2019, 12:57:23 PM »
The only caution would be the dipstick location clearing the manifolds. 
1981 C30 C&C under construction
1985 C30 Custom Deluxe Ext. cab 5.7L TH400 3.21 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
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Offline 75gmck25

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Re: 1986 305 to 350 Vortec Swap
« Reply #6 on: January 16, 2019, 09:10:21 PM »
I had to use a manifold spreader tool to get one of the manifolds back on my new heads, so I actually read the directions.  It worked very well.  They recommended also using the tool before you remove the manifolds so that you can remove sideways pressure and get the bolts to come out without binding.   The only local parts store that had the tool on hand was NAPA, but lots of places sold them online for $11-12.

Bruce
« Last Edit: January 16, 2019, 09:12:19 PM by 75gmck25 »

Offline JohnnyPopper

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Re: 1986 305 to 350 Vortec Swap
« Reply #7 on: January 17, 2019, 06:26:25 PM »
It's the little things...

Offline fitz

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Re: 1986 305 to 350 Vortec Swap
« Reply #8 on: January 17, 2019, 06:52:55 PM »
It's the little things...

1 more thing to look into is the distributor gear. You might need a different gear with the roller cam.