Stock Rocker Ratio?

[JMSII]

I knew this once, but I am getting old and feeble-minded!

Anybody know the ratio for stock 401 rockers? (Bridged)

Thanks!

[BREK]

I think all amc's are 1.6?

[amundaza]

Yes, all AMC V8's are 1.6 ratio.

I have read of someone installing Harland Sharp 1.65 PONTIAC rockers ... anyone else heard of this?

Sincerely,
GregTaylor
Oxford, MI
1989 Grand Wagoneer : Water/Hydrogen Injection 360-V8. 4.5" lift 31" BFG A/T's. Killer32 front bumper

[ol' school power]

Yes, all AMC V8's are 1.6 ratio.

I have read of someone installing Harland Sharp 1.65 PONTIAC rockers ... anyone else heard of this?

Sincerely,
GregTaylor
Oxford, MI
1989 Grand Wagoneer : Water/Hydrogen Injection 360-V8. 4.5" lift 31" BFG A/T's. Killer32 front bumper
I've been using them on my Ambassador for several years.

[amundaza]

I've been using them on my Ambassador for several years.

Was there anything special you needed to do to install them? Do you remember the Pontiac P/N's you installed? Lastly, do you like them ... how do they perform for you?

I'm also wondering if there might be any special benefit to running a 1.6 on the exhaust and a 1.65 on the intake, or vice versa, of someone is wanting to custom tailor head flow for optimum power.

Sincerely,
GregTaylor
Oxford, MI
1989 Grand Wagoneer : Water/Hydrogen Injection 360-V8. 4.5" lift 31" BFG A/T's. Killer32 front bumper

[ol' school power]

Greg
I don't remember the p/n. They were just off the shelf Harland Sharp Pontiac. You have to switch the studs to 7/16 stem instead of the AMC 3/8" top. Never tried the cam without them. It was spec'd at .490 lift with a stock ratio so I wanted to bump it up a bit. In mine, I had to use a longer pushrod probably due to how the cam was ground.
for anyone on a budget with early heads, you can use stock steel replacements for the Pontiac Ram Air IV engine (1.65) also if you use the stock 3/8 AMC rocker ball.
You can also get 1.7's, but the only problem is that the pushrod slots in the heads are a little inconsistent and may need to be machined a little further inboard.

[jeepsr4ever]

The whole reason for changing rocker ratios like that is to get that 92% or close to it for the intake/exhaust efficiency ratio.

[fifesjeep]

I have the 1.7:1 Harland Sharp Rollers on my 360... http://i7.photobucket.com/albums/y293/Fifesamcjeep82/000_0410.jpg
S4004-77 is 1.7:1 and 7/16" stud... the S4004 is the 1.6:1 and 3/8" stud...
If you bump up to the 1.65's and the 1.7's with the 7/16" stud the bottom of the rocker needs to be relieved...

[jeepsr4ever]

No, they actually relieve those for the factory stud shoulders otherwise they would share the same part number as the Ford small block rockers.

[fifesjeep]

No, they actually relieve those for the factory stud shoulders otherwise they would share the same part number as the Ford small block rockers.
Hmmm, I don't see how they would be relieved for the factory stud shoulders when these and the new studs are 7/16" and the bosses need to be machined in-order to achieve the proper geometry. Do the 3/8" studs and 7/16" studs use the same shoulders? I'm having a serious mental block (Brain fart)... :oops:

[jeepsr4ever]

Hmm good point! You got me! The relief is for the hex on the stud? :idea:

#-o

[ol' school power]

Bottleneck studs