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Author Topic:   rocker arm ratio and vaccum
maximus
Dirt Roller

Total posts: 21
posted August 23, 2005 10:28 AM  
I'm running a 355 with 1.5 ratio rocker arms and I have to pull 18 on the vaccum gauge at 850 rpms and I have done everthing I know to do and can only get 17.5 out of it.I don't want to switch cams so I was wondering if I put 1.6 ratio rocker arms on the intake valves will it pull more vaccum.(or is it the exhaust valves?) Thanks for any help.

STREET16
Dirt Maniac

Total posts: 158
posted August 24, 2005 02:23 PM  
I don't really have the answer for your question. But, I would think that 1.6's on the intake would allow you to open up the valve lash enough to get the extra half pound of vacuum - in theory. I tried a set of 1.6's withs stock heads and they bound up - the push rod holes have to be elongated. You might want to try a set of rhoades lifters, if you haven't already. I will keep an eye on your post, because I'd like to know too.

maximus
Dirt Roller

Total posts: 21
posted August 24, 2005 05:28 PM  
Thanks Street16 for the reply. I put the 1.6 on the intake side and it did not help, so I took them off and put them on the exhaust side and to my amazement I got 18 pounds (gauge fluctuates between 18 and 18.5) Next time I build an engine I think I will just get a cam with more lobe seperaion.

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