Hello, I am new to 225/6 engine. Please excuse my lack of knowledge. I have heard of rocker arms with a 1:6 ratio for the 225. The stock ratio for a 1966 225/6 is 1:5. Would there be any gains in switching to the 1:6 ratio as in performance with a stock cam. I know it would increase the lift but would it harm anything. If anyone has tried this could you tell me lash settings for 1:6 rockers. I have installed a Super six setup on car and motor is fresh, motor was built before I purchased car, so I would rather not pull cam,head etc... The car is a cruiser and I wanted to add just a little more breath to her. Sorry if its a foolish ? but I can't learn if I don't ask. Thanks for your time. 66 Dart Gt

Most of the stock rocker arms probably dont really measure 1.5 ratio. It is suppose to be 1.5, but in reality it is probably closer to 1.4:5 ratio or around there. So a set of 1.6 rocker will really open the valves quit a bit more than the stock rockers. The 1.6 rocker not only onpen the valves farther, but they open them faster, and keep them open longer. They would help a stock cam more than a aftermarket cam most of the time. As far as valve lash, it should be set the same as the stock rocker arms. And it should not hurt anything to run them, if anything it would help things last better. Like it would be easier on the valves & valve guides with the Roller Rockers, and they "should" stay in ajustment better than a stock rocker.


So yes its a good chance they could help your engine have more power & you still running a stock cam. The truth is though that you could probably spend that money ( New rockers are kinda expencive) on something that would help more than what the rockers will. But then again you say you dont want to take the engine apart and there is not a lot that can be done with out doing so. But still there is a little that can be done, for one, do you have good flowing exhaust on the car? Or even a header or a set of Dutra Duels. Either one of these would probably give you more power than the rocker arms would. What about recurving the distributor ? This is a good power & economy modification that is really cheap.


If you already have these two thing & the car already runs pretty good with more power than a stock engine then a little better rear end gear can pic things up pretty good. If the engine doesnt have good top end power though a gear is not something you want to do.


These few modifications I meantioned I would do before I did any rocker arm changes. If you already have these things & you just want a little more with out much work then the rockers would probably be a good way to go. But IMHO you would get more for your money doing the other things if you have not done them yet. Oh, one other easy cheap thing can be rejetting the carberator. There is ussally always some more power there, and if exhaust,timing curves and other things have been done the rejetting can help even more sometimes. It just depends on how far the carb is off. What about good hot ignition, have you done any upgrades to the igintion as far as better spark ( better coil, or even MSD box)? Sometimes good spark,carb & timing tuning can bring more power than anything you could bolt on. If all these things have been maximized then a gear change can make a big diff, but you dont want to gear your car to low for the type driving that you do.

I am not trying to say dont buy them, because they are a good add on for any setup really , its just they cost pretty much. If that is not a probablem for you I would get them. But if the budget is tight & you havnt done the other things it would be more for the money to go with the other things. Ofcourse you could always do all of them.





Jess

Hi Jess, WOW! Thanks for the reply and ideas. I really appreciate the clear and thoughtful response. I do have Dutra duals with 2 1/4 dual exhaust. I am getting ready to install a 3.55 ring and pinion. All of the other ideas you have passed along I have made a checklist and will follow. I am building the Dart with my 12 yr old and learning right along with him. It is a pleasure to share with my son the thoughtful help I have received from you and others here in this forum. Thanks again for your time. ED

In terms of $$ spent for power gained 1.6 rockers are a very poor choice. For what they will cost you can buy a good cam and lifters, and have change in your pocket.

If you check out the faster cars at the Slant races you will find many of them still wearing stock rockers.

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Hello, Thanks for your reply. Cost for return is a big issue for me. Thanks again for your help. Ed 1966 Dart Gt