|
10-21-2019, 10:33 AM
|
#1 |
|
landarts
 Join Date: May 2005
Location: Star, Idaho
Posts: 1,434
|
Help with manifold
I purchased a 68 1/2 ton about a week ago and trying to get it running. The truck has sat for a long time with bad gas left in the tank and fuel system. I am working all items to be cleaned out or replaced to get it going. The motor is a 283 and had a rebuild on it about 30K ago. I knew that the carburetor would need to be removed and rebuilt. When I tried to remove the carburetor the two front stud mounts basically were rusted through and snapped of with the slightest pressure. The two back ones were fine and no signs of rust.
I proceeded to pull of the intake manifold so I could work on getting the rusted carburetor mounts out and the threads cleaned up. As I was working on it I remembered that I had two intake manifolds from 327 motors. When I flipped them over to compare I noticed that the 327 manifold had the middle most port blocked off and the manifold from the 283 had the middle port open. Is it ok to use the 327 manifold with ports closed or do I need to stick with the 283 manifold and get the carburetor studs fixed. Pict 1 is the broken off studs in the 283 manifold Pict 2 is the two side by side for comparison Pict 3 is the truck I bought
__________________
Super Cheyenne aka the "Devil Cowboy" 71 K20 Idaho Edition 69 K10 from the Field 68 Second Chance Fix and Sale 72 GMC 3/4 ton 4x4 K2500 The "Fixrupr" build thread 72 Cheyenne 1/2 ton " FIXRUPR " - daily driver 67 C20 all original paint 71 K20 Custom 4x4 (Idaho Edition) 72 K20 GMC Super Custom 4x4 72 K20 Custom Deluxe 4x4 69 K10 Custom package 4x4 (69 K10 from the field) 72 K10 Custom 71 K10 Custom 72 K20 Custom Deluxe 4x4 72 K20 Crew Cab Project 71 GMC Jimmy CST 72 Blazer 70 Blazer |
|
|
|
10-21-2019, 10:46 AM
|
#2 |
|
Its a Truck Thing......
Join Date: Dec 2004
Location: Sierra Vista, Arizona
Posts: 3,179
|
Re: Help with manifold
Nice truck...
Basically you would be doing what is in this article: https://www.jalopyjournal.com/forum/...risers.247422/ If it is fine with you, do it. Are you using a Divorced Choke/Cable Operated/Electric Choke? A blocked port would affect the Divorced one in the cold. Smitty
__________________
71 C10 283/3SPD Full Resto 71 GMC 1500 Sierra Grande http://67-72chevytrucks.com/vboard/s...d.php?t=518599 70 C10 Suburban Former military GSA truck. 72 Chevy Blazer 4X4, Sloppy Jo, Mountain Climber. Wife says no more trucks. http://67-72chevytrucks.com/vboard/s...d.php?t=707378 72 GMC 1 Ton Motor Home, wife said no more trucks until she saw this one. Gen 3 6.0/4L80E 4.10 http://67-72chevytrucks.com/vboard/s...d.php?t=761110 68 GMC Suburban was 3/4 ton, now 1/2.Wife shook her head 71 C30 Wrecker 71 C20 Scott-Bilt As weird as it gets..BB Cheyenne AC Truck 68 GMC Long Stepside. They keep following me home 69 C30 Former Motor Home, Flat Bed time 70 G20 Red-E-Kamp Conversion "I'm your Boogy Van" |
|
|
|
|
10-21-2019, 10:47 AM
|
#3 | |
|
landarts
Join Date: May 2005
Location: Star, Idaho
Posts: 1,434
|
Re: Help with manifold
Quote:
__________________
Super Cheyenne aka the "Devil Cowboy" 71 K20 Idaho Edition 69 K10 from the Field 68 Second Chance Fix and Sale 72 GMC 3/4 ton 4x4 K2500 The "Fixrupr" build thread 72 Cheyenne 1/2 ton " FIXRUPR " - daily driver 67 C20 all original paint 71 K20 Custom 4x4 (Idaho Edition) 72 K20 GMC Super Custom 4x4 72 K20 Custom Deluxe 4x4 69 K10 Custom package 4x4 (69 K10 from the field) 72 K10 Custom 71 K10 Custom 72 K20 Custom Deluxe 4x4 72 K20 Crew Cab Project 71 GMC Jimmy CST 72 Blazer 70 Blazer |
|
|
|
|
|
10-21-2019, 10:54 AM
|
#4 |
|
Its a Truck Thing......
Join Date: Dec 2004
Location: Sierra Vista, Arizona
Posts: 3,179
|
Re: Help with manifold
That may not matter in your situation. Use either or....
Smitty
__________________
71 C10 283/3SPD Full Resto 71 GMC 1500 Sierra Grande http://67-72chevytrucks.com/vboard/s...d.php?t=518599 70 C10 Suburban Former military GSA truck. 72 Chevy Blazer 4X4, Sloppy Jo, Mountain Climber. Wife says no more trucks. http://67-72chevytrucks.com/vboard/s...d.php?t=707378 72 GMC 1 Ton Motor Home, wife said no more trucks until she saw this one. Gen 3 6.0/4L80E 4.10 http://67-72chevytrucks.com/vboard/s...d.php?t=761110 68 GMC Suburban was 3/4 ton, now 1/2.Wife shook her head 71 C30 Wrecker 71 C20 Scott-Bilt As weird as it gets..BB Cheyenne AC Truck 68 GMC Long Stepside. They keep following me home 69 C30 Former Motor Home, Flat Bed time 70 G20 Red-E-Kamp Conversion "I'm your Boogy Van" |
|
|
|
|
10-21-2019, 11:27 AM
|
#5 |
|
Registered User
Join Date: Oct 2016
Location: Dallas Texas
Posts: 3,329
|
Re: Help with manifold
.
...and now that you know...you can also get a set of gaskets that block those ports effectively disabling the heat risers. It's what I did on my BBC to help keep the intake cooler and minimize heat soak issues ( was having warm starting problems ). Hth, -klb
__________________
67 C10 fleet fuel injected '70 402, 700r4, 3.73 posi 07 335 sport turbo 6sp 94 Trans Am GT LT1 6sp posi -- sold after 22yrs 99 540 sport V8 6sp -- sold 73 240z L24 4sp -- given to friend 68 C10 step 350/350 3.73 open -- sold |
|
|
|
10-21-2019, 12:23 PM
|
#6 |
|
Account Suspended
 Join Date: Jul 2016
Location: Tacoma, WA
Posts: 6,873
|
Re: Help with manifold
The blocked passage is from carbon build up. Just drill and chisel it out.
|
|
|
|
|
10-21-2019, 08:26 PM
|
#7 |
|
Moderator
 
Join Date: Jun 2017
Location: Cherryville, NC
Posts: 2,210
|
Re: Help with manifold
Set the original manifold up in a drill press and drill out the original broken studs. If you need to, go one size bigger and use a helicoil to bring the thread back to standard size.
If you use the replacement manifold, clear out the carbon choked ports....
__________________
Family and country before all others... 2006 Chevy Silverado (Daily Driver) 2012 Chevy Equinox 
|
|
|
|
|
10-21-2019, 08:48 PM
|
#8 |
|
Registered User
 Join Date: Aug 2019
Location: Cheraw
Posts: 1,300
|
Re: Help with manifold
The 327 manifold is showing some rust in the #1 and #2 intake runners. That one will requier some clean up work. In the area of staying "original" I would fix the 283 manifold. Try soaking the studs with PB Blaster for a few days then try an EZ out.
|
|
|
|
|
10-21-2019, 09:01 PM
|
#9 | |
|
Registered User
Join Date: Jan 2007
Location: Puyallup, WA
Posts: 1,662
|
Re: Help with manifold
Quote:
__________________
72 C10 lwb fleetside -stock 350/350 combo |
|
|
|
|
|
10-21-2019, 10:14 PM
|
#10 |
|
Registered User
Join Date: Jan 2017
Location: Larkspur, Colorado
Posts: 916
|
Re: Help with manifold
Your 327 intake has considerably larger intake port opening so there will be a significant port size mismatch with the cylinder heads if they are correct for a 283. On a stock engine the port mismatch is unnoticeable in performance but if you use the 327 intake check very carefully that the larger ports don't create a vacuum leak at the port. If it were me I'd repair and run the 283 intake but I also have a torch setup that will almost certainly be required to get those broken studs out.
OR, hit the parts board here and post a WTB for a correct '68 307 intake setup and put her back to all original........... Steve weim55 Colorado |
|
|
|
|
10-22-2019, 09:28 AM
|
#11 |
|
landarts
Join Date: May 2005
Location: Star, Idaho
Posts: 1,434
|
Re: Help with manifold
I am leaning toward trying to fix the old 283 manifold. Ordered a Helicoil kit and have them soaking right now with Kroll oil. I will report the progress here shortly.
__________________
Super Cheyenne aka the "Devil Cowboy" 71 K20 Idaho Edition 69 K10 from the Field 68 Second Chance Fix and Sale 72 GMC 3/4 ton 4x4 K2500 The "Fixrupr" build thread 72 Cheyenne 1/2 ton " FIXRUPR " - daily driver 67 C20 all original paint 71 K20 Custom 4x4 (Idaho Edition) 72 K20 GMC Super Custom 4x4 72 K20 Custom Deluxe 4x4 69 K10 Custom package 4x4 (69 K10 from the field) 72 K10 Custom 71 K10 Custom 72 K20 Custom Deluxe 4x4 72 K20 Crew Cab Project 71 GMC Jimmy CST 72 Blazer 70 Blazer |
|
|
|
|
10-23-2019, 10:10 AM
|
#12 |
|
landarts
Join Date: May 2005
Location: Star, Idaho
Posts: 1,434
|
Re: Help with manifold
Well I soaked the two carburetor mounts that were broken off with Kroll oil a couple times a day for three days. Then I center punched it a few times with a carbide center punch and started drilling with a small bit and worked my way up in size. Going slow and adding some cutting lubricate as I go. I added a little heat with a Map gas torch and kept drilling and the first one finally came out on the drill bit. Moved onto the second one and had to go all the way, then used a 5/16 18NC tap and retapped it. Then used the tap to chase down the other three mount holes. When it was good and tested the mount screws, then took it out to side of garage and sprayed it down with dollar store oven cleaner to get all the gunk off and get it ready to reinstall.
__________________
Super Cheyenne aka the "Devil Cowboy" 71 K20 Idaho Edition 69 K10 from the Field 68 Second Chance Fix and Sale 72 GMC 3/4 ton 4x4 K2500 The "Fixrupr" build thread 72 Cheyenne 1/2 ton " FIXRUPR " - daily driver 67 C20 all original paint 71 K20 Custom 4x4 (Idaho Edition) 72 K20 GMC Super Custom 4x4 72 K20 Custom Deluxe 4x4 69 K10 Custom package 4x4 (69 K10 from the field) 72 K10 Custom 71 K10 Custom 72 K20 Custom Deluxe 4x4 72 K20 Crew Cab Project 71 GMC Jimmy CST 72 Blazer 70 Blazer |
|
|
|
|
10-25-2019, 07:54 PM
|
#13 |
|
Moderator
Join Date: Jun 2017
Location: Cherryville, NC
Posts: 2,210
|
Re: Help with manifold
I dont see a problem with your collection....
 if you run out of space you could always send me a few to look after for ya...
__________________
Family and country before all others... 2006 Chevy Silverado (Daily Driver) 2012 Chevy Equinox
|
|
|
|
 |
| Bookmarks |
|
|
Linear Mode
