Iīm going to buy new exhaust for my 271 fastech (thinking of GIL-style) and I need to know if 271 have standard or +3 in risers? I donīt have acces to the boat now so canīt measure the hight of the original exhaust holes in the stern. My new engine is hp500, previous had standard 496 mag. Many thanks for input.

HP500 came with "short risers" and then later "tall risers" because of reversion problems. Two pictures here show the difference, tall risers would be the preferred setup. My HP500 was a 1997 had the shorts, I then replaced with tall on the next motor rebuild. So it depends on the year of HP500 what is has on it.

Thx 97fastech, my question was really if the original exhaust-holes in the stern are standard hight or 3" higher in a 271 fastech, I've heard thay are 3" higher and need to verify that. In my old 271 sr1 i needed +3" blocks to use with standard merc 454 manifold

Fastech 271s that had the silent thunder exhaust have the exhaust holes in the transom in a weird non standard bravo spot. I had emi thunders with long risers and it put the exhaust hose in a bind and it started to burn the exhaust hose. I then switched to Eikert headers and they did not even come close to lining up. I ended up moving the holes in my transom to the standard bravo spot so I could run real headers. If you are buying aftermarket exhaust you better make sure the risers are short or your going to have a problem or you need custom tails on headers like cmi's. or just move the transom holes like I did. Jeff wurl

I had a 2000 271 Fastech with a built 500 EFI. EMI Thunder exhaust with standard 16" riser. Added a 1/2" aluminum block under the riser, elongated the mounting holes a tad to angle them inward and they worked fine.