96 TA

This old school performance guy told me YEARS ago when I was looking for roller rockers for my LT1 that I should put 1.6rrs on the intake and 1.5rr on the exhuast (actually i cant remember if it was the other way around). Anyways, he said there was a benifit over putting 1.6 on everything. Does that make sense? Is there in fact any benifit?

andysc

That is old school sbc. Back then the exhaust ports did not flow well, so they would put a 1.6 on the exhaust and 1.5 on the intake. Not necessary when working with modern cylinder heads. Will not hurt anything, but either go 1.5 all around or 1.6

hth

andy schuck

Injuneer

Depends how your cam was spec'd. My heads (CNC Cylinder Heads, Pinellas FL) flowed great on the intake, and a bit low on exhaust. To provide a margin of error, they spec'd the lobes to produce the same lift (~0.600") on the intake and exhaust, with 1.6X on the intake and 1.55X on the exhaust. The thought was if the exhaust showed up as restricted with the 0.600" lift, they could increase lift by going to a 1.6X rocker on the exhaust to try and improve performance.

96 TA

I see, so it really wouldn't be something someone with a stock cam should worry about would it? Im wondering since it is a stock LT1 cam that the car would see the maximum improvment with 1.6 all around.

lt1-xjs

Maximum improvement requires running 1.7's all around on the stock cam.