Hi ,
any one done a back to back test going from 1.5 ratio rockers to 1.6 ratio. Is it worth it to try in stead of going the whole cam change route. this is in reference to a 440 motor with 550lift cam. just wondering if the car liked it and would pick up a little.
thanks
Russ

all going to depends on if the heads can support the additional flow....

if they're lightly massaged 906's, probably not worth it. if they're full boogie SR's or eddie RPM, probably.

Hi ,
the heads are real max wedge heads so they have big ports and I'm putting in 2.14 intake valves to complement the 1.88 exh.
thanks

Steve D did a chassis dyno years ago, on a warmed up 440. He found a few HP over the 1.5's vs the 1.6's...I bet the old article is still up over at www.moparmusclemagazine.com I bet it would be worth less than 10 hp even on a Hot full bore race engine IMO.

I've done this on small blocks and most times seen a
improvement.... but only increasing the intake rockers,
gained nothing on the exhaust side(waste of money
doing the exhaust).... unless it was a REALLY small
exhaust lobe. But it will depend on your intake flow
weather it will improve... I should say at what lift

russ, you might have a clearance problem going to the 1:6 rockers with the pushrods .they might rub on the sides.
i had a problem and couldnt do the swap since my motor was already assembled.

I think if you have the right cam for the combo the gain will be small if any,If your cam is a little small and the heads can flow the extra lift you will see a good gain, For the most part the intake is more important unless you spray than the 1.6 on the exhaust will help alot

I've been fooling around with rocker arm ratios for awhile now and as far as I can tell, the engine always makes more power with more ratio. At least that is true on the intake side and of course, it is only true as long as the valve train can handle the extra stress.

I'm up to 1.85 on the intake side and 1.70 on the exhaust side. The next thing I might try is to drop the exhaust ratio down to 1.60 or 1.55 just to see what happens. My guess is that the power will only drop a small amount, maybe none at all.

Some engine builders have pushed up past 2.0 rocker arm ratios now in an attempt to get quicker valve action. I'm not sure what the Super Stock and Comp guys run these days but I'd be surprised if anyone was running 1.5 rocker arms in anything that was competitive.

Hi
ok here's the deal, the reason I'm asking, is when I built my max wedge clone based on a 440 short block, I used 906 heads and I hogged on the intake port to get the max wedge intake to fit , I welded up the heat cross over. I have true 11.1 comp. 550 lift comp cams roller cam. the car runs 12.30s with max wedge exhaust manifolds thru the cut outs. I have a brand new set of max wedge mopar perf. heads I bought 5yrs ago. I was saving them cause I was going to build a stroker motor, but now I want my son to run it with me in nostalga SS a few times and I wanted to get down to the 12:00 flat class. So I thought what the heck I'll throw the real heads on. and I thought to complement them I'd try the 1.6 rockers give it a little more cam. so now what do you think.
thanks
Russ

In theory you should see an improvement but the margin of improvement is in question due to what appears a lack of real-world experience feedback. I suggest you do a few base-line runs at Rock Falls raceway and then change to the 1.6 ratio on the exhaust side as per your plan and retest. Seems that there is not a lot of real world data on this to draw from the Mopar group and this would be good information for all going forward. Thanks in advance for letting us know how this turns out.

Basically the increased lift on the intake valve is worth the change,you won't see much from the exhaust side.Like Chris says,check your pushrod clearence.