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 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 11-07-2011, 01:30 AM   #1
Tuff Gong
Registered User
 
Tuff Gong's Avatar
 
Join Date: Jan 2011
Location: Glendale, AZ
Posts: 3,178
quick question

What is the correct pressure rating for a radiator cap on a stock 71 350?

Also how bad is it if you are running with a cap that is lower in pressure than what is required?

Thanks.
Tuff Gong is offline   Reply With Quote
Old 11-07-2011, 01:44 AM   #2
stich626
Account Suspended
 
Join Date: Sep 2010
Location: hingham ma
Posts: 1,721
Re: quick question

iirc the cap is 15psi.. might be 7 tho.. mine is 15
a lower cap will just lower the boil point of the coolant..
stich626 is offline   Reply With Quote
Old 11-07-2011, 05:26 PM   #3
Tuff Gong
Registered User
 
Tuff Gong's Avatar
 
Join Date: Jan 2011
Location: Glendale, AZ
Posts: 3,178
Re: quick question

Everyone else got any info on this.
Tuff Gong is offline   Reply With Quote
Old 11-07-2011, 05:36 PM   #4
a_barth
Registered User
 
Join Date: Jun 2010
Location: Eustis, FL
Posts: 124
Re: quick question

For some reason 13 sticks out in my head.
a_barth is offline   Reply With Quote
Old 11-07-2011, 06:09 PM   #5
slomotion
Old Duffer
 
slomotion's Avatar
 
Join Date: Mar 2003
Location: Maine
Posts: 1,821
Re: quick question

I agree with all of the above......13lb to 15lb, and for every lb of pressure you add, you increase your boiling temp three (3) degrees.
__________________
'68 Short C20 Flatbed Dually
w/ 292 4bbl, Langdon cast headers,
and WC T5 trans.

'81 G10 Shorty Van

"Good judgement comes from experience, and a lot of that comes from bad judgement." Will Rogers

"Under promise, then over achieve."
slomotion is offline   Reply With Quote
Old 11-07-2011, 07:39 PM   #6
longhorn70gmc
Senior Member
 
longhorn70gmc's Avatar
 
Join Date: Feb 2001
Location: Ridgecrest. CA, USA
Posts: 1,715
Re: quick question

I just had my 4 core redone in RENO NV at A-1 radiator shop and he went out of his way to tell me that I should be using a 16 PSI or higher. I asked him is it that way for SB and BB motors and he said it should be standard for the use of 4 core radiators. I hope this helps you.
R/
Billy
__________________
Billy

1970 GMC Sierra Grande 402/TH400
(Longhorn)14 years and counting rebuild!
1975 (Build) Chevrolet SWB 4X4 350 SB Lifted 6 inches
1970 Ford F250 Ranger 390 BB
2010 Ford Super Duty F250 XLT W/4 inch lift kit and Pro Comp Tires
Hub Cap Freak!
I need another truck like I need another hole in the head!
I'M IN THE MARKET...AS IT WERE!
longhorn70gmc is offline   Reply With Quote
Old 11-07-2011, 09:06 PM   #7
Tuff Gong
Registered User
 
Tuff Gong's Avatar
 
Join Date: Jan 2011
Location: Glendale, AZ
Posts: 3,178
Re: quick question

Helps me alot. Thanks for all the input. The PO of my truck put a 7 PSI cap on it. I am always running hot and losing water thru the overflow after long trips. I think the correct PSI may solve my problem. Thanks again.
Tuff Gong is offline   Reply With Quote
Old 11-07-2011, 10:06 PM   #8
NGN
Registered User
 
NGN's Avatar
 
Join Date: Nov 2001
Location: Old Bridge,NJ
Posts: 823
Re: quick question

I have a 14lbs Stant Lev-R-VenT on my 4 core radiator all for my L6-250 350 Turbo Auto Trans. Thats what the man at Fingers Radiator Shop recommended.
NGN is offline   Reply With Quote
Old 11-11-2011, 10:21 AM   #9
NGN
Registered User
 
NGN's Avatar
 
Join Date: Nov 2001
Location: Old Bridge,NJ
Posts: 823
Re: quick question

I forgot to mention my four core rad came out of 69-70 pick-up v/8 350 -350 auto trans with 14lbs cap , it all looked origenal.
NGN 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 09:49 AM.


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