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 Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 12-26-2008, 08:21 PM   #1
toomanytoyz
Luv the Crewcabs
 
toomanytoyz's Avatar
 
Join Date: Aug 2006
Location: Andrews, In. 46702
Posts: 4,085
1986 454, Square or Oval Port Head?

Got a Chance to buy a Edelbrock Manifold for a BBC, Seller stated it's for a Square Port Head. What Head Type will my Stock 86 454 Engine Have & Does it Make a Difference???

Thanks, Rick
__________________
55 Nomad
52 Willys Truck
67 Stepper
67 Fleet
68 Wrecker
68 Suburban
76 Crewcab
79 Gmc Dumptruck
84 Blazer
86 Crewcab Stepside
87 Iroc
89 GMC Plow Truck
91 Camaro Vert
96 Z71 Stepsde
toomanytoyz is offline   Reply With Quote
Old 12-26-2008, 08:31 PM   #2
f.monroe
Senior Member
 
f.monroe's Avatar
 
Join Date: May 2004
Location: Caldwell,Tx.
Posts: 3,343
Re: 1986 454, Square or Oval Port Head?

86 should have been peanut port head which is a small oval port head . The square port intake is for the early high performance heads that had square (rectangle) ports . I think that intake would do more harm than good on your truck .
Frank
__________________
Born and proudly residing in a Red State !
f.monroe is offline   Reply With Quote
Old 12-26-2008, 08:39 PM   #3
Livrat
Member #1049
 
Livrat's Avatar
 
Join Date: Jun 2000
Location: 25 miles east of Arlington, Wa. 4 miles west of Darrington, Wa.
Posts: 3,445
Re: 1986 454, Square or Oval Port Head?

Your 86 should be oval port.. although some had the "peanut ports"..
The square port intake will work on yours as long as you use square port intake gaskets.. (otherwise you will have a big vacuum leak!!)
Using that intake wont hurt but you will not really gain anything other than having an aluminum intake.

Last edited by Livrat; 12-26-2008 at 08:39 PM.
Livrat is offline   Reply With Quote
Old 12-26-2008, 08:53 PM   #4
toomanytoyz
Luv the Crewcabs
 
toomanytoyz's Avatar
 
Join Date: Aug 2006
Location: Andrews, In. 46702
Posts: 4,085
Re: 1986 454, Square or Oval Port Head?

Thanks for the Quick Responce, I was'nt sure which i had or if it would make any Difference................

Price is Really Good at $20.00, Just wanted to know if it was a worthwhile investment.

Thanks Again, Rick
__________________
55 Nomad
52 Willys Truck
67 Stepper
67 Fleet
68 Wrecker
68 Suburban
76 Crewcab
79 Gmc Dumptruck
84 Blazer
86 Crewcab Stepside
87 Iroc
89 GMC Plow Truck
91 Camaro Vert
96 Z71 Stepsde
toomanytoyz is offline   Reply With Quote
Old 12-27-2008, 06:21 AM   #5
grinch4om
dang its hot
 
grinch4om's Avatar
 
Join Date: Nov 2006
Location: frankfort kentucky
Posts: 1,348
Re: 1986 454, Square or Oval Port Head?

buy it and peddle it
grinch4om is offline   Reply With Quote
Old 12-27-2008, 08:36 AM   #6
LONGHAIR
just can't cover up my redneck
 
LONGHAIR's Avatar
 
Join Date: May 2004
Location: Columbus OH
Posts: 10,487
Re: 1986 454, Square or Oval Port Head?

I would not even try to use it....It will definately hurt performance and throw your fuel economy in the toilet.
The huge runner volume if the rectangular port manifold will kill the velocity of the incoming air/fuel charge. This results in low vacuum signals to the carburetor...poor throttle response, bad mileage. Then the air/fuel runs into the nasty edge of the smaller port in the heads, this results in what is called "fuel dropout". Fuel dropout is exacly what is sounds like, the fuel drops out of the air, resulting in poor burning...loss of power, stumbling, etc.

Not good.
LONGHAIR is offline   Reply With Quote
Old 12-28-2008, 05:45 AM   #7
James McClure
One shot, one kill.
 
Join Date: Dec 2007
Location: Saratoga Springs NY
Posts: 857
Re: 1986 454, Square or Oval Port Head?

Longhair forgot to mention oil dilution as also being a problem. You could get yourself a set of "open chamber heads" with 2.5" intake valves and 2" exhaust valves. Then you could use the intake, LOL. You'll hurt MPG though. I built one back in the 70's. All the goodies.600 horse at the rear wheels! Pick the front end of a 69 Chevelle 3 feet in the air w\14" wide slicks. Best track time was 9.9 sec at 148 MPH. Rear was a Brown spool and trans was a close ratio Muncie w\a vertigate shifter. A PITA to drive and really tough to get around corners, LOL. Wish I was that young and dumb again. Want a beasty? I'll build you one. jim
__________________
1984 K20 350M engine with 465,000 miles. Well, it's finally done!! Almost 2 years of work, but it was really worth the effort. Little stuff left to do is mount winch, wet sand & buff out and build belly pan\running boards. Body work takes lots and LOTS of beer!!!! God, Guts and Guns made America and God, Guts and Guns will preserve it! The worst thing you could do is get into my sights, but that don't matter, you'll never know it, cause you'll never hear the shotJim or Paladin whichever you choose.
James McClure is offline   Reply With Quote
Old 12-28-2008, 09:08 AM   #8
LONGHAIR
just can't cover up my redneck
 
LONGHAIR's Avatar
 
Join Date: May 2004
Location: Columbus OH
Posts: 10,487
Re: 1986 454, Square or Oval Port Head?

That's what the "etc." was for....LOL

Yes, you could swap the heads to match, but then you would need more compression to make that work too, then come the pistons...... So it's a whole new engine to go under that cheap intake...
LONGHAIR is offline   Reply With Quote
Old 12-28-2008, 09:12 AM   #9
BigBlocksRule
Registered User
 
Join Date: Jun 2008
Location: Lubbock, TX
Posts: 1,867
Re: 1986 454, Square or Oval Port Head?

Buy it, sell it and buy the correct one for your heads. Pull a valve cover and get the 6 or 7 digit casting number and post it back here. I'm betting the casting numbers end in 236 which is peanut ports. The Edelbrock Performer intake will fit those. If you have 781 or 049 castings, the Performer RPM or air gap will work. I wouldn't even try the big square port intake on smaller heads for the above mentioned reasons. It's actually worth more than the small port intakes, you should be able to sell it for enough to buy the correct one.
BigBlocksRule is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

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 -5. The time now is 05:09 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Copyright 1997-2013 67-72chevytrucks.com