Do I need adjustable Rockers with Hughes 318 whiplash cam?

[Gimike812]

I have a 70 318 block at the machine shop now with #675 small valve heads, the are just freshening up the block and heads, new bearings are being installed. I told the engine builder I have the Hughes 318 Whiplash camshaft and showed him the specs. He said that for my setup I will have to switch over from the 318 fixed rockers to a set of adjustable rockers or adjustable push rods, because the lift on the exhaust is over .500".

Is this true? Do I need to get different rockers and pushrods? Hughes Specs say the lobe lift for 1.5ratio rockers is .480" Intake and .516" Exhaust.

 

[moper]

Two comments....
1. Given the Mopar small block pushrod angles, there will be slightly less than .500 lift. Although lift has nothing really to do with rocker choice until you get a bit bigger.
2. Best bet would be to contact Hughes. Their cams like a decent spring, and may use an anti-pump-up lifter for it that require adjustablility in the rockers.

 

[d fark]

Hughes has been good to work with for us. X2 on the recommended spring. My engine builder questioned it but went with what Hughes recommended