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Discussion Starter · #1 ·
Hi all. I have searched through a lot of the posts here and can't seem to find an answer, so, here goes. I have a 67, 396 that was bored 30 over when I bought it. The car has been off the road for the last 15 years. With no lead in today's gas, I know I need to put new heads on. I'm going aluminum to keep it lighter. The questions is: do I need to change the cam if I want roller rockers ? Anything else I might need to know for the swap ?
Thank you for any info, Dom
 

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Yes roller rockers are fine. Be aware the most aftermkt aluminum heads are around 115-120 cc. combustion chambers. The small bore 396-402 needs 106-109 chambers to produce a decent compression ratio. Early L-88 chevy or just have hard seats installed in your present heads.
 

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You do not need to worry too much. Changing to roller rockers will be fine.Now changing to roller LIFTERS...different story. As far as roller rockers you need to
Be aware of lift ratio...some rocker arms are 1.5 to 1 and some are 1.6 to one etc. The increase in ratio effectively increases valve lift and consequently reduces valve to piston clearance. Also you need to determine if your heads can handle the increase in lift, as that will cause coil bind if excessive, and also if high enough, the retainer can "crash" into the guide top/valve seal.
Chances are if you go with 1.6 to 1 you will be OK, but it still needs to be verified.Also with increased lift by changing the ratio is a chance that the pushrods will deflect (flex) .
For every action-there is an equal but opposite reaction
 

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Discussion Starter · #4 ·
Good and bad news huh.
Thank you ! I didn't realize I was going too big with the aluminums. Just wanted to save the weight.
I'll look for a set of early L-88 heads first but I'll probably end up with going for hardened seats.

Thank you again !
 

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Discussion Starter · #5 ·
LATech.
Crap ! totally forgot about the different height. remember reading about that.
thank you for the reminder. I think, at this point, to make it easier, I'm gong to
go with the hardened seats for now and work on the rest a little at a time.
At least I will be having fun with the old engine.
 

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BBC stock rockers are 1.7-1 so anything less will cut your valve lift and big blocks love lift. I have a 1/2 set of 1.6 Harland Sharps on the counter for many years. Used the other half set on a cam that had way too much exhaust lift. Solved the problem, but nobody else wants the leftovers..
 

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You should also check to make sure the rockers are properly aligned with the valve tips. You may need a different length push rods when changing to a different style rocker.
 
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