Changing rocker arm ratio??
Thread Starter
Burning Brakes
Joined: Feb 2009
Posts: 780
Likes: 1
From: Shelby NC
Changing rocker arm ratio??
Have a SB 350 with 3863151 style cam and 1.5 ratio stock rockers. Running World Products Sportsman heads 64cc 200 runners 2.02 intake valves. Would it be worth cahnging to 1.6 ratio rockers for performance and would I have to change valve covers to a tall design--have factory alum style now?? Thanks for any help---
Safety Car
Joined: Nov 2005
Posts: 3,961
Likes: 573
From: Lompoc, CA. Santa Barbara County
I went from 1.5 stock rockers to 1.6 and then 1.65 ratio roller rockers. At first I kept my stock L-82 valve covers, but I had to have the drip rails machined off.
Bee Jay
Bee Jay
Safety Car
Joined: Nov 2008
Posts: 4,368
Likes: 9
From: Colorado
I have 1.6 rockers on the sportsman head you have and it all works. The pushrod guide holes are supposed to be enlarged if you do go to a 1.6 though. I really don't know if mine were enlarged but I don't see any real wear on the pushrods with ~1500 miles on them. I use the standard valve covers with a THICK gasket. Talls weren't going to work very well due to interferences with things like the brake booster vacuum line.
Safety Car
Joined: Nov 2008
Posts: 4,368
Likes: 9
From: Colorado
This is essentially a totally new engine, cam, crank, pistons, intake, heads so all I can say is it has great power. You need to pay very close attention to valve train geometry because the 1.6 changes your coil bind on springs as well as other relationships. I had to replace all valve springs just a short while ago because we were off on spec. New springs and it's awesome. Do searches and you will see posts where people experience a loss of power with 1.6 due to such things.
You can't just toss in 1.6 rockers and expect it to work.
You can't just toss in 1.6 rockers and expect it to work.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
In terms of HP/$$ benefit, rocker arm ratio is probably one of the costliest changes to add any power to your engine. It's usually one of the last components to 'throw' at an engine rebuild. Any benefit to a street engine would be difficult to prove (less than a 'handful' of HP).
Le Mans Master
Joined: Nov 2008
Posts: 5,691
Likes: 12
From: columbus oh
In terms of HP/$$ benefit, rocker arm ratio is probably one of the costliest changes to add any power to your engine. It's usually one of the last components to 'throw' at an engine rebuild. Any benefit to a street engine would be difficult to prove (less than a 'handful' of HP).
