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Norbert Sliwinski
(28 posts)

08/11/2012 05:20PM

Main British Car:
1973 MGB GM 2.8 V6

DIY Exhaust
Posted by: NAS1966
Date: December 12, 2018 02:20PM

Hi All,

I am looking for data for a DIY header and exhaust pipes for my 2.8 V6 for my '74 MGB restoration project.
There where a bunch of people who made their own but no one gave pipe sizes i.e. primary and secondary
OD pipe diameters.

According to my calculations the primary ( header ) pipes should be 1 5/8 ID or 1 7/8 OD and the main
exhaust pipes after the collector should be 2 ID or 2 1/16 OD

Also I saw one set-up which had a couple of nice rectangular mufflers - does anyone have data for those?
Can anyone concur with these above pipe sizes or which size pipes should I be using?

Carl Floyd
Kingsport, TN
(3700 posts)

10/23/2007 11:32PM

Main British Car:
79 MGB, Buick 215

authors avatar
Re: DIY Exhaust
Posted by: MGBV8
Date: December 13, 2018 08:06AM

IMO, your primaries are too large. Except for all out high RPM efforts, smaller is better. I run 1 5/8" primary headers on a 400hp 350 V8.




Scott Costanzo
Columbus, Ohio
(540 posts)

10/25/2007 11:30AM

Main British Car:
1968 MGB GM 5.3 LS4 V8

authors avatar
Re: DIY Exhaust
Posted by: Scott68B
Date: December 13, 2018 04:48PM

I used 1 1/2" primaries on my 3.1 headers with 2 1/4" collectors. I got guidance from Headers by Ed when I sized things.

Rob Ficalora
Willis, TX
(2618 posts)

10/24/2007 02:46PM

Main British Car:
'76 MGB w/CB front, Sebring rear, early metal dash Ford 302

authors avatar
Re: DIY Exhaust
Posted by: rficalora
Date: December 13, 2018 04:54PM

For the mufflers you referred to, check out [spintechmufflers.com].

I use their cruiser series on my car. They are great for clearance, but I wish the sounds was a bit deeper.

Norbert Sliwinski

(10 posts)

08/04/2018 08:01PM

Main British Car:

Re: DIY Exhaust
Posted by: 7399MGM
Date: February 20, 2019 03:51PM

Thank you for your input

Dan Jones
Dan Jones
St. Louis, Missouri
(268 posts)

07/21/2008 03:32PM

Main British Car:
1980 Triumph TR8 3.5L Rover V8

Re: DIY Exhaust
Posted by: Dan Jones
Date: February 21, 2019 05:04PM

If your 60 degree V6 doesn't have unevenly spaced pulses competing for space in the collectors, you want them to be smaller in diameter than what would be run in an equivalent 90 degree non-flat plane V8. I'll have to check my notes but we are running well over 600 HP through 2 1/2" ID collectors with out 180 degree headers instead of the usual 3 1/2" ID for a 4-into-1 header.

Dan Jones

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