Hello,

 My name's Randall. I'm new on here & have never been on a forum before, so please excuse if I post stuff in the wrong place, etc. I've been in & around jet boats all my life sans  the last 15 years or  so............  A couple of weeks ago I found a decent deal (cheap) on a '75 Tahiti 18" jet, so I bought it & viola! I'm back into jet boats again. So this thing has a 455 olds in it. The guy advertised it as "ready for the water". When I looked at it I noticed that a head bolt "head" is broken off. Ready for the water my a**. I have a considerable amount of oldsmobile parts @ home including a ready to run 403 olds. While I have the 455 out to go through it, I was thinking of running the 403. What I'm concerned about is exhaust width @ the transom Vs @ the snail outlets. The 455 is considerably wider than the 403, is it too much for the exhaust hoses to compensate for?