w/z exhaust manifolds on small block
February 20th, 2009, 10:46 PM
#1
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w/z exhaust manifolds on small block
Has anyone ever tried using the w and z big block exhaust manifolds on a SBO? I'd like to use them when I put my 350 back in my 70 cutlass. Is it possible to use them or will they not fit? I have a set of thornton reproductions w/z manifolds and I'd rather not buy another manifold set for my 350 if I don't have to.... Thanks!!
February 21st, 2009, 05:01 AM
#3
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Location: West Hartford, CT
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They will bolt onto the head but will encounter interference @ oil filter adapter, and possibly starter. They are made for big block which has a higher deck so the angle is different.
I have often wondered if the flange that bolts to the head could be milled/ground to change the angle or whether it would make sense to have an adapter plate made that would do the same or would one of these methods even work? Would you then be fighting upper control arm/stud clearance?
I have pondered this but never seriously examined it. I looked @ the Thornton SBO manifolds hoping for the ideal compromise but they didn't quite hit the mark for me - nice thought & execution but not enough increased volume or truly independent runners. So, one of my cars has headers & the other has plain old 350 manifolds. If somebody needed to buy new manifolds, liked the design of the Thornton SBO manifold(xover flange deleted, small seperater for middle ports) and wouldn't fret over a non authentic part on their car, then they look like a good choice.
I think you should do some R & D on seeing if the W/Z can be made to fit & work without issue, maybe start w/ adapter plate to at least get an idea for angle & thickness(W/Z have enough meat to change angle enough?-doubtful) and let us know!
My cars are on the road so I will never get to it but this comes up frequently & could be of benefit to many if it would work.
I have often wondered if the flange that bolts to the head could be milled/ground to change the angle or whether it would make sense to have an adapter plate made that would do the same or would one of these methods even work? Would you then be fighting upper control arm/stud clearance?
I have pondered this but never seriously examined it. I looked @ the Thornton SBO manifolds hoping for the ideal compromise but they didn't quite hit the mark for me - nice thought & execution but not enough increased volume or truly independent runners. So, one of my cars has headers & the other has plain old 350 manifolds. If somebody needed to buy new manifolds, liked the design of the Thornton SBO manifold(xover flange deleted, small seperater for middle ports) and wouldn't fret over a non authentic part on their car, then they look like a good choice.
I think you should do some R & D on seeing if the W/Z can be made to fit & work without issue, maybe start w/ adapter plate to at least get an idea for angle & thickness(W/Z have enough meat to change angle enough?-doubtful) and let us know!
My cars are on the road so I will never get to it but this comes up frequently & could be of benefit to many if it would work.
February 21st, 2009, 08:07 AM
#4
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yeah I guess I'll try to shove them in there and see what happens. Otherwise I'll either have to get a thornton set, find some on ebay, or attempt to salvage some from the junkyard. My original 350 manifolds were both broken when I took them off 
February 21st, 2009, 09:29 AM
#11
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Join Date: Mar 2007
Location: Northern VA
Posts: 47,661
No, they don't, which is why the factory never offered them, even on the W-31. About once every couple of years someone who doesn't believe this spends a couple of weeks fighting with them, only to find that they hit the motor mounts, starter, oil filter adapter, etc.
Yes, they will bolt to the SBO heads. They will NOT clear in the chassis. Olds used the extra room due to the taller BBO deck height to form the individual runners on these manifolds. The SBO doesn't have this room.
Once again, if this worked, it would have been common knowledge 20 years ago.
Yes, they will bolt to the SBO heads. They will NOT clear in the chassis. Olds used the extra room due to the taller BBO deck height to form the individual runners on these manifolds. The SBO doesn't have this room.
Once again, if this worked, it would have been common knowledge 20 years ago.
February 21st, 2009, 03:37 PM
#13
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Sorry, I completely skipped over this line when I was reading. Maybe I thought it was part of your signature or maybe I'm drunk who knows. Are you willing to ship these?
February 21st, 2009, 04:43 PM
#14
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February 21st, 2009, 04:44 PM
#15
Seasoned beater pilot.
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February 21st, 2009, 08:54 PM
#17
Seasoned beater pilot.
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4 are pending...
I have an oddball passenger side for a 70's 350 cutlass here as well, if someone just needs one.
$10 a manifold.
I should have a fresh batch coming in next month too. The junkyard is crushing everything, so hopefully, I'm going to swoop in with some more lowball offers.
You pay what I pay....I'm just trying to save some good junk.
I have an oddball passenger side for a 70's 350 cutlass here as well, if someone just needs one.
$10 a manifold.
I should have a fresh batch coming in next month too. The junkyard is crushing everything, so hopefully, I'm going to swoop in with some more lowball offers.
You pay what I pay....I'm just trying to save some good junk.
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