not sure what to do , the boat came with twin aq171 , but exhaust manifolds are hard to come by. and how long do used ones last,, so do i
change to aq151 using the aq171 bottom end and fit an 8v head or look for some good aq171 manifolds and use the aq171 . your thoughts please
thankyou

There are companies making stainless steel exhaust manifolds to both Aq171 and Aq151....

Link to stainless steel exhaust manifold.

Brg Johan

http://drevdelar.se/rostfri-rostfria-avgaslimpa-aq171-aq170

thankyou , do you know how much they are

Nope, I'd guess between 1000-1500€ each.

think i will switch to 151 there is plenty of parts , am i right in thinking i can use the 171 bottom end and just fit an 8v cylinder head
thanks

I guess you can do that, but I don't know if the fresh water cooling system from the aq171 still fits if you change the cylinder head to 8v. Put the question on the attached link.
I think he has done something similar.
If you go the 8v way you should buy cylinder heads with the casting number "531", they are the original mounted on AQ151.
In the car world they come from turbo machines.
Good luck!

http://www.ockelbo.plars.org/guestbook/

thankyou , so the cylinder head from a normally aspirated engine will not do ?? i thought they were the same

You will loose power, because the flow is better in the 531 top than in the na tops(530), so try to get 531 tops.

ok thanks , does the car 531 have a v cam

No, not the turbo ones.
Earlier I wasn't quite honest with you, the top is available in very few examples in na cars the engine is referred to as B230FB(I think) but now I'm out in deep water.
I don't know where the V cams are mounted.

You can also fit a K-camshaft.

do you know what k camshaft were mounted to ,,
thankyou

Volvo 240 GLT, engine B23E something between 1980-1984(?)
At least here in Sweden.