Poly 318 vs LA 318 Rocker Shafts?????

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xLURKxDOGx

xLURKxDOGx

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Are they the same? There are a few poly engines at a yard near me and I figured since all poly engines were adjustable rockers they all had banana rockers but wasn’t sure if they’re the same as LA arms. Anyone have any info on that I would be greatly appreciated.

Thanks,
Jake
 
Different locations for holddown hardware and different locations for the rocker arms
 
Poly head=semi hemi not a wedge head.

poly-rocker-arm.jpg
 
how about using the drivers side intake rockers on the passenger side head LA cylinder ? would it be offset away from the port ala W2's?
 
W2 rockers are slrsslrs. eiieeiie

L rockers are srsrsrsr. eieieiei

s=straight
l=left
r=right
i=intake
e=exhaust
Never heard of switching rockers between the wedge and poly.
 
If any of those motors has a 4bbl or 2x4 bbl manifold on them buy it. They are very pricey.
 
Jadaharabi said:
Poly head=semi hemi not a wedge head.

View attachment 1715284845
Click to expand...
Is that a 318 poly or an older 313. My 1967 had hydraulic lifters and non adjustable rockers. My 66 had solid lifters and adjustable rockers. I also thought the valves were inline. But I could be mistaken as the last 1 I did was in the mid 70s. Kim
 
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The wedge has the inline valves.

valves-2.jpg


Poolyspherical head engines


Semi-Hemi” Polyspherical Head V8 Engines:
241, 259, 270, 301, 315, 325, 331, 354

Engineer Pete Hagenbuch wrote:

I don't know who invented the word “polyspherical” but the design was supposed to maintain the characteristics of the true hemi with one rocker shaft and attendant cost savings. What it wasn’twas a wedge chamber with inline valve stems.

 
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Jadaharabi said:
W2 rockers are slrsslrs. eiieeiie

L rockers are srsrsrsr. eieieiei

s=straight
l=left
r=right
i=intake
e=exhaust
Never heard of switching rockers between the wedge and poly.
Click to expand...
I see what you are saying but if you take the rockers off the shafts of the Poly and put them on the LA shafts in the order needed, would the Poly offset arms work as the offset W2 intakes? I would illustrate this but I don't know how to do that; sometimes my verbal descriptions leave things out...just ask my Wife.
 
abdywgn said:
I see what you are saying but if you take the rockers off the shafts of the Poly and put them on the LA shafts in the order needed, would the Poly offset arms work as the offset W2 intakes? I would illustrate this but I don't know how to do that; sometimes my verbal descriptions leave things out...just ask my Wife.
Click to expand...
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Look at the picture. The rocker tip is pass the side of the body of the rocker arm. No it won't work.
 
383Scampman said:
I' love to see a 331 or 354 poly .
Click to expand...
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They made the 354 Hemi and the 354 poly at the same time but I think most of the 354 Polys went to Canada.

The 1958 354 engine was available in both Hemi and Poly form; with four barrel carburetors, the Hemi produced 350 horsepower, and the Poly just 310. Still, the Poly was much cheaper and lighter, and the company could make larger engines to replace the lost power
 
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