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 > General Forums > Alternate Tinkerings

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 04-28-2017, 12:20 PM   #1
davepl
Registered User
 
davepl's Avatar
 
Join Date: Aug 2006
Location: Redmond, WA
Posts: 6,332
69 Pontiac 2+2

My 2+2 is in Hemmings Muscle Machines this month (still "Coming soon", but I guess it'll be up soon):

https://www.hemmings.com/magazine/mu...e/3750916.html

I've had it in this bone-stock config for a good ten years now, and I'm thinking I'd like to do a largely hidden conversion back to headers and EFI. I'm sure I'm giving up a literal 150hp with the iron exhaust manifolds and intake on this. It ran 12.9 with headers, a Holley 850, and automatic. It has a 5-speed now, but feels more like a 15 second car. The exhaust REALLY chokes it I think.

I'm wondering if there's a big performance benefit to full-length headers over 3/4s, or do 3/4s get you 90% of the benefit of full length tubes?

Are 3/4s easier to live with? I've never really had problems with headers other than plug access, so that wouldn't be much different anyway.

Put more simply, if ultimate power isn't the goal, are there benefits to 3/4 length headers?
Attached Images
 
__________________
1970 GMC Sierra Grande Custom Camper - Built, not Bought
1969 Pontiac 2+2 427/390 4-speed Coupe
1969 Pontiac 2+2 427/390 4-speed Convertible
davepl is offline   Reply With Quote
Old 04-30-2017, 05:08 PM   #2
Advanced Design
Senior Member
 
Advanced Design's Avatar
 
Join Date: Jul 2012
Location: Oblong, Illinois
Posts: 7,028
Re: 69 Pontiac 2+2

Well, I can't provide personal experience on the headers so will defer to others. Beautiful car Dave! I hadn't seen it before. Loved the pic's of your parents and your son too.
Advanced Design 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 10:54 AM.


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