"15 to 40 horsepower"? from rockers only?

well i was just browsing at summit the other day and My attention turned to these little babies, i was wondering if buying these rockers would get me the supposedly "15 to 40 horses" like it said. OR i would have to get new springs and valves for it to really work. they said that it was the low friction and low weight that would give me the power. any thoughts?
heres the link
:http://store.summitracing.com/partdetail.asp?part=CSP-S4003&autoview=sku

 

I slapped on a used set of Crane roller rockers (for GT40 and P heads) and I haven't been able to run it at the track because the setup sucks too much gas for my carb to handle now. I bumped up to 1.7.

The rollers themselves are supposed to add the 20HP and cool the engine down because of less valve-train friction. Then there is the extra .020-.030 lift which should strengthen up the engines pull...

 

Getting back 15 hp isn't unheard of with roller rockers. They don't make power, they free up some that is normally lost through friction. Stiff springs and high lift cams cause a lot of friction at the trunion area with stock-type rocker arms. You really don't gain as much from the roller tip but it helps keep from side-loading the valve stem and wearing out the valve guides.

 

I have the cheapie crane magnum rollers(all steel) on my mav with the 1.7:1 ratio.They definitely decrease parasitic losses in the valve train as well as the increased ratio affording me a little more grunt.40 HP? I guess its possible but I think its an overly optimistic figure.I would think the low end of 10 to 12 HP is more like it.Maybe 15-16 If your cam/heads really like the lift increase.Just my 2 pennies.

 

so if i get those it would be a good thing for the engines life and give me "some" power and which ones should i get(brand recommendation)

 

Mine have bearings at the roller tip and at the mount. Should drop much friction with all the bearings.

 

These work ONLY with GT40 and GT40P heads. Just unbolt the old stamped rockers, bolt these on, use a shim or two if it doesn't line up.

Plus, my heads are good for .500 lift and this brought my exhaust lift up to .502, intake up to .478.

But, as soon as I put them on, It sounded better, takes off better, but when the secondaries open up, it falls on it's face. Also seems to be running hotter, making me think I am running my carb too lean. I have swapped to the richest jet/metering rod combo and has improved, but not enough to go to the track. I am currently looking for a 750 carb to swap to.

 

If your heads are not pedestal type like scoopers gt 40 ps' but stud mount you will need to have guided(rail type) rockers.Yes you can get them in full roller designe like you want.If you are useing push rod guide plates then you dont need rail type rockers.A rocker stud upgrade might be in order down the road if you go to stiffer valve springs and or a lumpy cam.

 

GT40 heads are fairly cheap, and easy to find. Plus, the head swap alone might get you 20-30 HP...

Then tack on the roller rockers... and you can pick up some more new-found power.

 

well i just dont know where to start with my upgrading becuasei i have a bone stock engine exept for spark plugs and wires but its running great. i just dont know if i should get a carb and intake first or get heads and cam, or get headers and duals(once i get my column moved to the floor). or get a distributor and and Msd Coil. DONT KNOW WHERE TO START

 

The "correct" way to do it is to decide what you finally want, in the end.

Then identify all the parts that will go with that setup, and start to buy them one at a time until you are ready to rebuild.

But, like most of us on here, you will fail miserably at this...

If I were you, and I am not much advanced compared to you on your car...

Start with new intake and carb, go 4 barrel, for sure, try to get better than the base model Performer intake. You really need to have a good idea what you plan on doing with the car in the end.

I knew I would be buying and re-buying parts, so I started with a Performer 289 intake, and now have a heavily ported Torker 289. I started with an Edelbrock 1406 600cfm carb which was a great carb. Until I added better heads, headers, dual flowmaster exhaust, and most recently the 1.7 roller rockers which maxed out my carb. I was always able to richen the carb up a bit to handle the increased flow with each mod, but this last one maxed out the carb.

I plan on going through at least 2 more intakes, 2 or 3 more carbs, another set of heads, and at least 1 more cam before I finally get that 6-71 blower snapped onto the top of this 302

But the best and cheapest way is to know what you want/need first, and not go through all of this trial and error stuff like I have...

 

If your just wanting to buy some rockers that will work w/ a stock older model head... buy a set of roller tip rockers. THey make them that will work on these. I have them on my heads. Get those roller tip rockers, and a set of Posi-locks so you can set the clearances and you will be amazed how much better it runs.

 

10 hp for the rockers and 30 hp for the stickers that come with them

 

i would change the cam and lifters, intake and carb, and headers first. then a new set of heads. to do the cam and lifters you need to remove the intake so you might as well do that at the same time. carbs can be expensive. i really don't trust these to be bought on ebay. i run a holley 750hp. (Approx $650). you can probably find a good 650 from someone on here. headers can be changed at any time. i ran a set of comp cams roller tip rockers til i went with the crane gold roller rockers.

 

Always start with the exhaust.