engine swap/manifold problems

[chaddemler1980]

here is a little clarification. I had a 305 merc in my boat, the motor was shot. I bought a new motor "a 350" from an old dealer who said it to was a merc from another boat which he had rebuilt. well i can not find a set of exhaust manifolds for the motor. I tried the old ones which naturally wont fit, and then i bought a set from a marina which i saw came off a 350 boat and even these will not fit, upon further inspection of the "new" motor i see that they have steel center bolt head covers "not original merc ones" which leads me to believe that maybe the motor has just an old set of truck heads bolted on, my question is how do i find a set of merc exhaust mannifolds for this motor? it looks to be a standard 4 bolt mounting pattern for the mannifolds, but both sets i already purchased do not match up.

 

[Bt Doctur]

Re: engine swap/manifold problems

all small block chevy V8 heads have the same dimentions.
283,327,348,350,
either you did not buy a chevy or you bought a big block.
post a pic on this new engine.

 

[chaddemler1980]

Re: engine swap/manifold problems

it is 100% for sure a a chevy 350 but for some reason the exhaust mannifolds i had from my 305 and the new ones i bought for a chevy 350 did not fit "wrong bolt pattern" dont know where to look anymore ill post pics if you need but it is a chevy 350 motor. just got call from marina that i bought heads from and they said they gave a set of big block mannifolds... so now hopefully when i go pick up a set of 350 mannifolds they will fit.

 

[TilliamWe]

Re: engine swap/manifold problems

Chad, the valve covers indicate that the motor you now have was produced sometime from 1987 to present day. That's all it means.
But regardless, the physical dimensions and exhaust manifold bolt patterns are the same on every Chevy small block head. Any exhaust manifold for a Chevy Small Block will bolt up.

 

[chaddemler1980]

Re: engine swap/manifold problems

ok now i just got done fitting up the manifolds i got from the marina and again the mounting holes do not line up. the holes on my engine are 4 evenly spaced holes and both mannifolds i have tried the 2 end holes match up but the 2 center holes on the mannifolds are closer together than the holes on the motor by almost an inch on each one. I will take some pics of the mounting holes on the motor and of the merc mannifolds i got from the marina, oddly enough they are the same pattern as the ones from my old motor... Just dont get it, its getting puzzling not to mention frustrating!

 

[TilliamWe]

Re: engine swap/manifold problems

Chad, on a small block Chevy, if your inner two exhaust manifold bolts are 1 inch closer to each other than the bolt holes on the head, then they are in the middle of an exhaust port. At this point a picture of both your heads and your exhaust manifolds would be very helpful.

 

[chaddemler1980]

Re: engine swap/manifold problems

I feel like an idiot, i got it figured out. the marina gave me by accident the first time a set of big block mannifolds, the second time around i got a set of v-6 mannifolds and i never even looked at em to realize it. should have it done by monday. thanks alot guys.

 

[TilliamWe]

Re: engine swap/manifold problems

Well, that's okay Chad. At least you've got it right now. We all just "knew" it had to be something simple, cause the exhaust port arrangement on a SBC make it kind of unique and hard to mess up! Best o' luck to ya!