Ive got 2 beautiful twin sidedraft dellorto carbs sitting in my house and ive finally decided that they need to go on my car. I would love to pull the whole intake/exhaust manifold off and put on some nice extractors at the same time but $money$ is a big issue. So the only other option (that i can see) is to split the current manifold, use the exhaust part and put on a new inlet manifold for the dellorto's. The only problem i can see is that i need to make sure the new manifold will 'fit' with the old one.

Any thoughts/tips/warnings? This is a pretty big step for me so any help would be greatly appreciated!

Cheers,
Evan

1972 142S

Thanks for all the info everyone, i knew i could count on the brickboard! I think i will try to suss out a FI manifold and go from there. If i cant find one ill get out the grinder. Very handy to know that IPD have some headers for sale, only prob is that im over in australia. Oh well.

Thanks again,
Evan

1972 142S

I've cut a number of manifolds with a cutting disk on an angle grinder, no problem, grinding the manifold so the washer are level, fiddly but also no problem, getting an early FI manifold,best option and cheap but impossible around here, but maybe easy where you live, using a late FI manifold -- tricky cast iron welding to fill the holes for the sensors. If you can source some single carb manifolds cheaply ( they should be very cheap or free ) get one of those as it is easier to get at the joint with a grinder and you keep your manifold intact.
Hans

I just got my new vintage flyer from IPD, and they've got headers on sale for $170. Seems like a damn good deal to me...I'd got for that were I you.

-Matt
--
-Matt '70 145s, '65 1800s, '66 122s wagon, others inc. '53 XK120 FHC

You should be able to find a good FI exhaust manifold for cheap.
Then you won't have to worry too much about fit and you won't be
ruining an otherwise good manifold. There is some risk in doing
what you propose, btw.
--
George Downs, Bartlesville, Oklahoma, Central US

I'm with George on getting a used exhaust manifold but beware!

Manifold came in two thicknesses. 9/16" and 11/16" Your new intake and exhaust flanges must be the same or you will not get proper sealing at the gasket and will experience bent and broken studs.

My FI exhaust manifold was 11/16" and my intake manifold (carbs) was 9/16" so I had a local shop spot-face the exhaust at the four shared "ears" to 9/16" to avoid having to mess with stepped washers (although that is perfectly OK).

Mike!

If you want to cut the manifold, I have used a Milwaukee 4 1/2 inch grinder with a cut-off wheel to do this on a few of the one-piece manifolds. I caution you against using a welding torche because the thermal stress on the manifold can warp the seating surface and propagate internal cracks and fissures that will show up later. It would be easier to find a B20F exhaust manifold. I've seen someone make a custom carb set-up using a cut B20F intake manifold and welding an aluminum plate to the input ports, but that was for a 4 carb set-up.

On the different thickness manifold flanges, I broke a nice aluminum intake manifold from a B18B even using the proper stepped washer thickness. When the manifolds heat up, they expand at different rates and any small difference in washer height can crack the intake flanges.
--
'89 245 Sportwagon, '04 V70 2.5T Sportwagon