Downpipe thoughts and suggestions

As Jimmy Hilton know we are in the process of de smogging a 75 car...the
poor thing has the headpipe san cat that hooks right onto the bastard
manifold....got to have a new downpipe ....there are two, the early version
and the late....since this will be hooked onto either the existing muffler etc
or a Peco I would assume the late version would be best since it has a
single pipe of some length and that length might be helpful. Anyone been
here before and have any thoughts.

Jim

Are you going with two carbs or one??
Edit: I've always used the early style to go with the early exhaust manifold.

Probably twin HS4's Chris....somewhere we have an uninstalled Weber kit but
I think we will go with the SU on this car and put the Weber on one of the
other kits....I am like everyone around here in that the SU's ought to be on
MG's but at some point I want to give the Weber a shot just to see how
it preforms....that is if I can avoid the rocks and arrows that will be coming
my direction. Jim

I hate Webers and have for a life time yet bought a TR6 with twin Webers. There was a reason for all that hatred.

I grew up with T types and the MGA and agree with you Chris...my desire to
try the Weber off sometime in the future is like hitting youself in the head
with a hammer...it will only feel really good when you quit ....and when you
throw the Webers out....which headpipe would you think best...me the one
up to 74/75 or so.

The simple way is to just use the OEM manifold and add an OEM down pipe. There are any number of outfits that make them. When you go to do the swap you should pay attention to the intake manifold flange thickness. It should match the thickness of the exhaust manifold flanges. If not you have to make up a stepped washer so that the pressure of the stud nut as it is tightened is applied equally to both manifolds.

Jack

I scratch my head in amazement every time I think of a TR6 with dual downdraft Webers.

Jim,

I always use the '68 - 74 downpipe, regardless of which manifold, on a conversion.

TR6 should have dual sidedraft Webers (subtle poke at Chris). :)

My 75 has twin SU's from a 71 and the 68-74 exhaust manifold and down pipe.

Oh yeah, a pair of DCOEs is real subtle!! :)
My choice would also be the stock manifold and downpipe for the MGB up to 1974. Apologies if confusing earlier; headers weren't even in my consideration.

Michael Fliegel Wrote:

I am always amazed when I hear talk of hanging two or even one DCOE on the side of an MG or a Triumph. I am positive that some here have had success with them on MGs but I never did, well maybe a little using a single carb on a warmed over B motor. The fact is that those things are designed basically to allow gobs of air and gasoline into an engine and the engine innards themselves will determine the success rate. It makes sense to me that if the engine is stock or relatively so it can gobble up just so much charge and using a DCOE or similar to dump lots in will only create disappointment and frustration. Sort of like those pseudo muscle cars lurching down the street with a huge Holly sitting on top of a stock 327. I suppose that a full out race motor like something that Hap or Basil would build could benefit, but for the rest of us I think that the big honkin' Italian mixers are just eye candy.

Jack

twigworker Wrote: