Newbie question about rocker ratio

[ozmoparjoe]

Hi everyone, i'm just chasing some info on rockers and rocker ratio's.
I have a 1968 383 and need to replace the rockers as they are worn where the shaft goes through, this is the comp cam i have for it Mutha' Thumpr 235/249 Hydraulic Flat Cam and Lifter Kit for Chrysler 383-440
Heads are factory 906, i'm just a bit confused on weather i need to buy 1.5 or 1.6 ratio rockers? Comp cams tell me factory rockers will be ok to use so will these from 440 source be ok? Rocker Arm & Shaft Assembly - New-440 Source
If not, happy to listen to suggestions of aftermarket rockers that might be a better choice. The engine will be just a mild build, nothing crazy so not looking to buy the most expensive stuff out there. Also keen on any info on push rods too.
Thanks!

 

[scampy]

I see that cam recommends a spring change,make sure you are using matching springs.Those rockers would be ok 1.5 is the stock ratio,can't recommend 1.6 without measuring esp with a cam change already.You can go adjustable if the budget is there but then pushrods needed for sure which you may need anyways with the other changes for length.Smith brothers can make you whatever you may need for pushrods at reasonable price but you will prob be ok.

 

[Demonic]

The factory advertised ratio is 1.5, but can often measure out to 1.45 or so. Unusual for factory stock rockers to wear badly in a stock motor, unless it suffered oil issues in it's life.

 

[ozmoparjoe]

I see that cam recommends a spring change,make sure you are using matching springs.Those rockers would be ok 1.5 is the stock ratio,can't recommend 1.6 without measuring esp with a cam change already.You can go adjustable if the budget is there but then pushrods needed for sure which you may need anyways with the other changes for length.Smith brothers can make you whatever you may need for pushrods at reasonable price but you will prob be ok.

Yes i actually purchased a complete kit from Comp that includes the springs as well.
Thanks.

 

[ozmoparjoe]

I do believe there may have been an oil issue before i purchased the engine as one of the pushrods was bent.

 

[ozmoparjoe]

Thanks for the info guys.

 

[dano]

The problem is aftermarket rockers can be a bit all over the place for geometry.

*edit, I will add that is not just a Chrysler or shaft rocker thing, its for every make.

Go here and do some reading.

http://www.b3racingengines.com/

Is your 383 in the car or being assembled?

 

[SuperStock426]

Hi everyone, i'm just chasing some info on rockers and rocker ratio's.
I have a 1968 383 and need to replace the rockers as they are worn where the shaft goes through, this is the comp cam i have for it Mutha' Thumpr 235/249 Hydraulic Flat Cam and Lifter Kit for Chrysler 383-440
Heads are factory 906, i'm just a bit confused on weather i need to buy 1.5 or 1.6 ratio rockers? Comp cams tell me factory rockers will be ok to use so will these from 440 source be ok? Rocker Arm & Shaft Assembly - New-440 Source
If not, happy to listen to suggestions of aftermarket rockers that might be a better choice. The engine will be just a mild build, nothing crazy so not looking to buy the most expensive stuff out there. Also keen on any info on push rods too.
Thanks!

If it were me I would go with adjustable rockers..For one they are true 1.5 ratio and the factory rockers are not very precise which in turn going with 1.5 adjustables will get more out of your camshaft..I've used the Harland Sharp roller rockers..Not the ones that have the needle bearings but the ones they make that are bushed..I bought mine through Mancini and they're a decent set of rockers..Once again I'll say that going with the adjustables will let you get the full potential out of your camshaft...Another issue I've seen out of stock rockers that have some wear and age on them is the tip of the pushrods pushing through the rocker arm when going to a bigger cam and stiffer springs.

 

[ozmoparjoe]

The problem is aftermarket rockers can be a bit all over the place for geometry.

*edit, I will add that is not just a Chrysler or shaft rocker thing, its for every make.

Go here and do some reading.

http://www.b3racingengines.com/

Is your 383 in the car or being assembled?

Thanks, i will have a look later tonight. Engine is out of the car and disassembled.

 

[ozmoparjoe]

If it were me I would go with adjustable rockers..For one they are true 1.5 ratio and the factory rockers are not very precise which in turn going with 1.5 adjustables will get more out of your camshaft..I've used the Harland Sharp roller rockers..Not the ones that have the needle bearings but the ones they make that are bushed..I bought mine through Mancini and they're a decent set of rockers..Once again I'll say that going with the adjustables will let you get the full potential out of your camshaft...Another issue I've seen out of stock rockers that have some wear and age on them is the tip of the pushrods pushing through the rocker arm when going to a bigger cam and stiffer springs.

I did see those Harland rockers for sale but are a bit out of my price range unfortunately, being in Australia, by the time i receive them it will be twice the purchase price.
What about factory style adjustables? I have seen them on 440source, perhaps they are a good alternative?

 

[SuperStock426]

I did see those Harland rockers for sale but are a bit out of my price range unfortunately, being in Australia, by the time i receive them it will be twice the purchase price.
What about factory style adjustables? I have seen them on 440source, perhaps they are a good alternative?

I really can't say about them..I've never used them..Maybe you can do some research and find out some info on them

 

[dano]

Have you looked at the Yella Terra rockers? I've read they are pretty good, but that's it.

 

[SuperStock426]

I did see those Harland rockers for sale but are a bit out of my price range unfortunately, being in Australia, by the time i receive them it will be twice the purchase price.
What about factory style adjustables? I have seen them on 440source, perhaps they are a good alternative?

Mancini Racing Aluminum Roller Rocker Arm Kit