1.5 vs 1.6 Rockers

[jefflock]

I am running a Lunati cam. It has the advertized duration of 292 and 480 lift. If I change to 1.6 rockers how much will my lift increase? Will I see any performance gains? Seat of the pants or time slips only? That is the question.
Thanks Jeff

 

[sweatybetty]

assuming that 480 lift is figured with 1.5 rockers, with 1.6 rockers lift would be 512

 

[rumblefish360]

The math looks like this;

.480 divided by 1.5 = .32 Then multiply .32 by 1.6 to equal .512

.480/1.5 X 1.6 = .512

Will I see any performance gains? Seat of the pants or time slips only? That is the question.

The answer is; Yes, you should see a performance gain. Time slip only.

 

[jefflock]

Sometimes my math skills suck. Along with spelling. My kids tell me I must be getting old. Can't wait to here their kids tell them the same thing.

Changing it to 512 lift should help at the strip shouldn't it?
Thanks Jeff

When I posted this note Rumblefish, I saw your response.
Thanks Jeff

 

[lead69]

Just an opinion but I would change the cam instead,its more work but you wont have to mess with pushrods,geometry ect.Also any real h.p. gain would depend on the flow of your heads,if there stock then theres really no gains to be had.Ive had experinece with the cam you have in a couple cars (one a 318 dart) and its really a non agressive grind,advertised as a 292 but only 230 @ .050.,Im thinking you could really pick up some power from an upgrade.

 

[abodyhotrod]

i have the same cam and looking for more power to thaught about rollers or 1.6 ratio rockers but it gets expensive. lunati has sum bigger cams like the 513/533 and bigger 533/542 sumthin like that it seems alot cheaper to do just the cam. but how much lift can we use on the j heads.

 

[lead69]

i have the same cam and looking for more power to thaught about rollers or 1.6 ratio rockers but it gets expensive. lunati has sum bigger cams like the 513/533 and bigger 533/542 sumthin like that it seems alot cheaper to do just the cam. but how much lift can we use on the j heads.

It really depends on whats been done with the heads,positive seals,installed height,retainers ect.I know my 360 smog heads heads with viton seals and stock retainers were good to around 540 with aftermarket springs.

 

[rumblefish360]

lead, where does the head stall in it's lift?

 

[lead69]

lead, where does the head stall in it's lift?

Most of the stock heads Ive seen are between the high .400s to .500 max,it really depends alot on the valve job ect.In this case it seems a cam change would provide alot more power than a increase in lift-the lunati braket master is a pos for .006 vs. .050 and I had the unfortuante experince of seeing how badly they stacked up lol.My machinist has never really seen big gains in stock heads from over .500 lift cams but more duration works to provide more area under the curve so to speak.But now with serdi type/multi angle valve grinds ect.,it nice to have modern higher lift cams for the duration,my heads have a 50 degree seat and the transitions incredible.