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 01-29-2013, 12:20 PM   #1
t5noel
Registered User
 
Join Date: Dec 2011
Location: Maryville, TN
Posts: 34
350 Serpentine belt conversion and intake gasket

I know there are a ton of threads concerning serpentine belt conversion and I searched it all before I opened a new thread.

While reading up on installing 350 intake gaskets I found out that the gaskets on engines with a reverse water pump (serpentine setups) had the two rear water ports blocked. I am in the process of putting a new 350 in my 74 GMC truck with a serpentine system. The 74 350 did not have the rear ports blocked. Should I buy the intake gaskets with the rear ports blocked? Is it an issue at all?

I also noticed while digging around that the 99 Suburban with a 350 did not have the rear ports blocked. I might also add that I'm putting an aluminum intake on it.

There has to be someone out there a lot smarter than me that can explain this.
t5noel is offline   Reply With Quote
Old 01-29-2013, 04:56 PM   #2
gchemist
BAD BOW-Silverado XST
 
gchemist's Avatar
 
Join Date: May 2000
Location: Senior Member from Austin, TX
Posts: 6,431
Re: 350 Serpentine belt conversion and intake gasket

Welcome to the site. I have an serpentine conversion on my truck. Does the new intake have a water cross over path? If so leave them unplugged. I know mine are not plugged and I run a RPM Air gap intake. Use a nice bead of RTV on both sides of the intake gaskets. Use a very large bead at the front and rear block wall where they match the intake. Use a dap under the corners too. All of the RTV will prevent oil and water leaks. Depending on the intake, you may want to use aircraft forma-a-seal on the bolt threads. The sealer will prevent oil seeping up the bolts onto the intake.
__________________
Gerardo a.k.a. Mad Chemist
Silverado XST videos
gchemist is offline   Reply With Quote
Old 01-30-2013, 10:32 AM   #3
mopar346
Registered User
 
Join Date: Jan 2011
Location: Quincy, FL
Posts: 533
Re: 350 Serpentine belt conversion and intake gasket

Quote:
Originally Posted by gchemist View Post
Use a nice bead of RTV on both sides of the intake gaskets. Use a very large bead at the front and rear block wall where they match the intake. Use a dap under the corners too. All of the RTV will prevent oil and water leaks
Did you mean RTV only on the water ports or on the whole gasket? My concern with RTV on the intake ports is that it would bead up inside the port when bolted together tightly causing a ridge that would create turbolance and hendering flow. I realize this would matter little on 90% of the engines out there.

Welcome to the forum Noel. Perry, FL??? GA??? and I'm sure there are others.
mopar346 is offline   Reply With Quote
Old 01-30-2013, 04:09 AM   #4
wraprail
Registered User
 
wraprail's Avatar
 
Join Date: Sep 2010
Location: Lake Havasu City Arizona
Posts: 863
Re: 350 Serpentine belt conversion and intake gasket

Most (if not all) aftermarket intakes block off the rear water ports from the heads. Back in the day we used to drill/tap -4 AN fittings and run hose from there to the thormostat housing on both sides to remove steam pockets from the heads on our race motors. I think they are suposed to be blocked otherwise
wraprail is offline   Reply With Quote
Old 01-30-2013, 12:06 PM   #5
gchemist
BAD BOW-Silverado XST
 
gchemist's Avatar
 
Join Date: May 2000
Location: Senior Member from Austin, TX
Posts: 6,431
Re: 350 Serpentine belt conversion and intake gasket

Only on the water ports. A realy small bead will work. Just make a circle. Use a little dap under the gasket corners where the block, intake, and head meet. I did this on my ZZ4. I have no oil leaks anywhere on my engine.
__________________
Gerardo a.k.a. Mad Chemist
Silverado XST videos
gchemist is offline   Reply With Quote
Old 01-30-2013, 12:20 PM   #6
mopar346
Registered User
 
Join Date: Jan 2011
Location: Quincy, FL
Posts: 533
Re: 350 Serpentine belt conversion and intake gasket

That has always been my practice as well, I just read it funny and was curious.
mopar346 is offline   Reply With Quote
Old 01-30-2013, 10:38 PM   #7
t5noel
Registered User
 
Join Date: Dec 2011
Location: Maryville, TN
Posts: 34
Re: 350 Serpentine belt conversion and intake gasket

Thanks everyone for the comments. I checked the intake more closely and found the rear ports are blocked. Newby mistake. I bought the intake gaskets for a 74 which had all the ports open which confused me. I will just use the gasket I bought and get some RTV for the ends and ports holes. Some thread sealer for the bolts as well.

I got my setup from a 99 Suburban because I wanted the A4 AC compressor and the 140 amp alternator. The water pump was a little different too. It has two tubes protruding from the top. One goes to the return line for the heater and the other goes to the radiator. So unless I want to try squeezing a suburban radiator in my 74 I'll just plug the other tube. It goes against my grain. I like doing things right. Jerry rigging is not my thing.
t5noel is offline   Reply With Quote
Old 03-28-2013, 09:25 PM   #8
t5noel
Registered User
 
Join Date: Dec 2011
Location: Maryville, TN
Posts: 34
Re: 350 Serpentine belt conversion and intake gasket

Here is the progess on the engine so far. Installed the serpentine belt system and rebuilt quadrajet. The serpentine passenger side was a bit of a challenge. The bolt holes did not match up. Lucky for me I have a friend that was a GM engineer. He welded me a bracket that bolted from the intake down to the exhaust manifold. Worked great!
Attached Images
     
t5noel is offline   Reply With Quote
Old 01-20-2016, 08:28 PM   #9
Undone
Registered User
 
Join Date: Aug 2010
Location: commerce ga
Posts: 896
Re: 350 Serpentine belt conversion and intake gasket

Quote:
Originally Posted by t5noel View Post
Here is the progess on the engine so far. Installed the serpentine belt system and rebuilt quadrajet. The serpentine passenger side was a bit of a challenge. The bolt holes did not match up. Lucky for me I have a friend that was a GM engineer. He welded me a bracket that bolted from the intake down to the exhaust manifold. Worked great!
What did you do to get the alternator to work?
Undone is offline   Reply With Quote
Old 01-20-2016, 09:20 PM   #10
gmachinz
Account Suspended
 
Join Date: Jun 2011
Location: Des Moines, IA.
Posts: 4,143
Re: 350 Serpentine belt conversion and intake gasket

The Vortec RH serpentine brackets have provisions for either style of alternator-105A or 140A.
gmachinz is offline   Reply With Quote
Old 01-20-2016, 09:22 PM   #11
gmachinz
Account Suspended
 
Join Date: Jun 2011
Location: Des Moines, IA.
Posts: 4,143
Re: 350 Serpentine belt conversion and intake gasket

For folks running the older style serpentine setup who want to run a 140A alternator, I build bracket kits for them.
Attached Images
  
gmachinz is offline   Reply With Quote
Old 02-20-2016, 09:20 PM   #12
berencam
Registered User
 
berencam's Avatar
 
Join Date: Aug 2007
Location: branson mo
Posts: 933
Re: 350 Serpentine belt conversion and intake gasket

Sorry for necrobumping this thread but I'm having similar issues with this same serpentine setup. Do you have any more pictures of that adapter you made for the passenger side bracket
__________________
69 chevy c10 350 3 speed manual wood bed build thread here r.i.p.
70 c10 auto 350 build here
berencam is offline   Reply With Quote
Old 03-28-2013, 11:46 PM   #13
maxxxy
Registered User
 
maxxxy's Avatar
 
Join Date: Jul 2010
Location: Norman, Oklahoma
Posts: 557
Re: 350 Serpentine belt conversion and intake gasket

Are there multiple serpentine bracket set ups? The setup on my motor is a little different. Different brackets and tensioner and idler are swapped.

__________________
Max

Max's bagged 81

81 rcsb bagged, 22s, build in progress
09 ext cab, 24" U2's, DD sub/amp
maxxxy is offline   Reply With Quote
Old 03-29-2013, 08:53 AM   #14
UATahoe
Registered User
 
Join Date: Mar 2012
Location: Huntsville, AL
Posts: 1,000
Re: 350 Serpentine belt conversion and intake gasket

Surprised to hear that the bolt holes were off. Everything i have read says it should be a direct swap. Strange. I am getting ready to tackle this on my project as well, but i will be using a newer vortec block.
UATahoe is offline   Reply With Quote
Old 03-29-2013, 11:43 AM   #15
MalibuSSwagon
Registered User
 
Join Date: Sep 2009
Location: Weare,NH
Posts: 1,592
Re: 350 Serpentine belt conversion and intake gasket

Its not quite jerry-rigging, its more like retro-fitting.

I'd stick with the intake gaskets recommended for the intake. In my case, I have a 1986 305 and I happened to have a 1986 TPI manifold. No water crossover in the rear, but it still used the 86 intake gaskets with the crossover ports. I believe GM updated the gaskets in 87 to save on cost, they eliminated iron manifolds with the rear crossover so 2 gasket designs were no longer needed.
MalibuSSwagon is offline   Reply With Quote
Old 03-29-2013, 05:33 PM   #16
rs72z
Registered User
 
rs72z's Avatar
 
Join Date: Oct 2011
Location: Emory TX
Posts: 900
Re: 350 Serpentine belt conversion and intake gasket

If i'm not mistaken the picture the op posted is from a 96-97 vortec style engine. yes?
__________________
___________________

78 ccsb dually
5.3
4l60e
http://67-72chevytrucks.com/vboard/s...d.php?t=491551
rs72z is offline   Reply With Quote
Old 03-29-2013, 05:44 PM   #17
t5noel
Registered User
 
Join Date: Dec 2011
Location: Maryville, TN
Posts: 34
Re: 350 Serpentine belt conversion and intake gasket

The serpentine system pictured above came off a 1999 Suburban with a 5.7L engine. Same as a 350.The heads are larger than the older 350 with a carburetor because of the fuel injection system I suppose.
t5noel is offline   Reply With Quote
Old 11-22-2015, 03:46 PM   #18
84lngbed
Registered User
 
Join Date: Nov 2014
Location: severn md
Posts: 48
Re: 350 Serpentine belt conversion and intake gasket

Was wondering if you using the p/s pump from the 99 suburban? Cause I'm doing the same swap now on my 84.
84lngbed is offline   Reply With Quote
Old 11-22-2015, 04:23 PM   #19
MalibuSSwagon
Registered User
 
Join Date: Sep 2009
Location: Weare,NH
Posts: 1,592
Re: 350 Serpentine belt conversion and intake gasket

Quote:
Originally Posted by 84lngbed View Post
Was wondering if you using the p/s pump from the 99 suburban? Cause I'm doing the same swap now on my 84.
It's the same Saginaw pump, just the reservoir may be different to fit the bracket. Just swap reservoirs if thats the case.
MalibuSSwagon is offline   Reply With Quote
Old 11-22-2015, 04:26 PM   #20
t5noel
Registered User
 
Join Date: Dec 2011
Location: Maryville, TN
Posts: 34
Re: 350 Serpentine belt conversion and intake gasket

Yes I did. Do you need a bracket the one that I talked about above? I can put you in touch with the guy that put mine together.
t5noel is offline   Reply With Quote
Old 11-22-2015, 08:42 PM   #21
84lngbed
Registered User
 
Join Date: Nov 2014
Location: severn md
Posts: 48
Re: 350 Serpentine belt conversion and intake gasket

Quote:
Originally Posted by t5noel View Post
Yes I did. Do you need a bracket the one that I talked about above? I can put you in touch with the guy that put mine together.
I'll let you know. I have summit heads on my motor. So I'll see if it bolt up to the 3 holes.
84lngbed is offline   Reply With Quote
Reply

Bookmarks


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 11:46 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com