4AG 20V extractors on 16V Head

**cannonball** · 24-07-2006, 10:58 AM

I seem to recall somewhere in the deep cavernous recesses of my mind that a 20V manifold can be made to fit a 16v Head if the stud holes are modified in some way. Is this true? and other than the stud location, what else is different between the 16v head and a 20V (as far as Exh port size/location etc.....whatever is important to enable/disable this swap)?

Basically, can you bolt a set of 20V extractors to a 16V head? (both RWD format)

**Ben Wilson** · 24-07-2006, 11:01 AM

The outer two holes are relocated a little. You can get away with slotting the two outer holes and it should all be good. The size/location of the ports is the same.

**BigWorm** · 24-07-2006, 12:27 PM

Here's some pics of a 16V gasket compared to a 20V flange. As you can see & as ben said, the ports are the same it's just the 2 outer holes that are different. As to whether slotting the outer holes will work ok, I don't like the look of it on that side in the 3rd pic, but you can decide.

**Ben Wilson** · 24-07-2006, 01:28 PM

I've slotted 16v extractors and fitted them to a 20v before with no problem.

Here's a set of 20v extractors using a 16v gasket:

The mismatch in your third pic should work OK.

**cannonball** · 24-07-2006, 04:17 PM

Hmm, ok, the extractors I am looking at are a custom built set, so I will have to see if there is enough meat on the mounting face to deal with the offset of those studs. Thanks guys, nice pics too

**BigWorm** · 24-07-2006, 09:35 PM

Hey how about we chuck this in FAQ? It seems to come up every now & then.

**waternolo** · 24-07-2011, 08:16 AM

Hi guys, just bumping this thread up as I have a few queries. I know 20v extractors will fit by slotting them.

My question is, are they the same length as the 16v extractors? Will my exhaust, have to be lengthened in any way in order to keep the entire system the same length? Has it also got the same mounting point for the o2 sensor and are they the same thread size?

Cheers,

Ciarán