I have a 70 f-100 with a swapped out 351w. I am considering roller rockers while my heads are in the shop. The cam and lifters are hydralic with a four barrel. I have stock rockers that are bolted in (not the stud kind). Crane has roller rockers for $199.99, that is a little more than I am willing to spend. I found some on E-Bay for $124.00, that seems to be more in my price range. What am I going to need as far as installation? Do I need to fit my heads with studs or can I use the bolts that my currant rockers use? What would be a good brand of rocker?

 

Sounds like you've got a 78-up 351W with pedestal rockers. If so, then the Crane Energizers/Cobra roller rockers will work. Just bolt them down, torqing the bolts to 25 ft/lbs and go. I can't accurately recommend another brand, never having tried the others, but the Crane made-Ford "Cobra" 1.7's last forever. The set I've got on one of my engines now, I bought used and I think the guy I bought em from said they had 100K miles on em. I've had them for nearly 5 years now and had zero problems with em. And I've had them on three different motors now.

 

Would I have to replace the push rods with 1.7's or have problems with my valve cover's clearing the rockers? I heard that the 1.6's would work, ant suggestions about the 1.6's ?

 

No pushrod changes with 1.7's. As for valve cover clearance, that's going to depend on your covers, there's no difference between 1.6 and 1.7's in that regard. Some covers have more room inside than others. It's usually the filler baffles that interfer with roller rockers.

 

The 1.6's are a step down from the 1.7's, right? If so, what would the gain be with the 1.7's? Are there any other cosiderations I need to know about before begining on this project?

 

The 1.6 isn't really a downgrade. It's the stock ratio. The 1.7's get more lift without much more duration.

 

1.7's give you .030 more lift at the valve. But if you already have 1.6 roller rockers, don't run out and buy 1.7's. The time to use 1.7's is before you buy 1.6's. They cost the same, so it's a bit more cost effective to go with 1.7's from the start.

 

ive just been wondering this and havent asked in the post ive seen on it so figured nows a good time. ive always went with the rockers the cam recomends which is usually 1.6. Yet i see allot of people going to 1.7 is there a reason the cam doesnt suggest either or?

 

Good question! That deserves a good answer. There are some people that say, "you need to change your rods, get guide plates and even change your cam." Whats the scoop?

 

There ARE a few cam's that are recommended to use with 1.7's (Comp Cams XE264HR, XE270HR, and the XE276HR are a few) But otherwise the reason for 1.7's is to gain a bit more lift without changing cams, and in the case of 1.7 roller rockers, the lift gained, plus the reduction in friction and the stabilized ratio (the rockers don't flex like stamped steel does) all add up to more power for your dollar. The only requirement for guide plates would be with factory stud mount heads that have pressed in studs and rail rockers. Using non-rail rockers in place of factory rail rockers, requires the installation of guide plates and to do that, you have to replace the pressed in studs with screw in types for there to be a way to secure the guide plates to the heads. Pedestal heads may not be as capable as stud types in strength with bigger cams, but for mild applications, they do fine and there are a few choices in pedestal mount roller rockers for Fords, since Ford chose this route with the 93 Cobra's powerplant. There is no specific cam requirement as far as ratio goes. You can use any ratio with any cam as long as there are no clearance issues resulting from the increased lift. Some racers even go so far as mixing rocker ratios to optimize engine output (one ratio for the intake and a different ratio for exhaust)

 

ah okay im running this cam from comp cams.

http://store.summitracing.com/partde...5&autoview=sku

and it had recomended 1.6 rockers so i went with them and convered the heads to screw in studs and guide plates.

 

Even with 1.6 rockers you'd do well to check the clearances with that cam. Long duration, combined with the lift it's got may put the valves closer to the pistons than you want. It's not just the lift that gets things tight, but the duration, valve relief depth & shape, and head gasket thickness. Pretty healthy cam there. Better use the recommended springs with it too.

 

yep i did im also running domed pistons so i checked all the clearances, the valve springs they said to use are actualy double springs

 

I really do not want to sound troublesome- but how do you go about checking the clearances with a cam? I am sure I could find it another post, but dial-up is really slow these days.

 

put playdo on the pistons bolt the head down with a used head gasket and put the rockers on etc and torque it down, crank it over by hand. then take it off and mesure how thick the indentation is in the playdo. Thats how my dad used to do it when running dome pistons and big cams. And we also had decked my block to up the compression so it was important to check the clearing hehe. hope that helps