[mitchc]

What is the diffrence between the raised and flat guide plates for a SBC? In what application would you want a raised over a flat?

Thanks Mitch

[oldbogie]

Originally Posted by mitchc

What is the diffrence between the raised and flat guide plates for a SBC? In what application would you want a raised over a flat?

Thanks Mitch

What exactly are we talking about here?

I interpret your term "raised" for the typical aftermarket roller lifters that are permanently joined in pairs with an articulated alignment bar.

Similarly, I interpret flat as being the factory dog bones that drop over the top of the lifter which engages a machined flats on opposite sides of the lifter, The dog bones being retained by a spider or by a stud and nut in the middle of the dog bone which projects from the block between lifter pairs.

Bogie

[mitchc]

I'm talking about pushrod guide plates.

Originally Posted by oldbogie

What exactly are we talking about here?

I interpret your term "raised" for the typical aftermarket roller lifters that are permanently joined in pairs with an articulated alignment bar.

Similarly, I interpret flat as being the factory dog bones that drop over the top of the lifter which engages a machined flats on opposite sides of the lifter, The dog bones being retained by a spider or by a stud and nut in the middle of the dog bone which projects from the block between lifter pairs.

Bogie

[oldbogie]

Originally Posted by mitchc

I'm talking about pushrod guide plates.

Sorry I have camshafts and lifters on my mind today.

OK so the question is those which are raised higher toward the rocker rather than those which are just flat.

I've used both, I fantasize that the raised provide more stable support for the pushrod when spring pressures are at a competition level and the revs are high. But can't say I've seen any significant difference in terms of performance or wear between them.

Bogie

[techinspector1]

Probably no big deal either way, but I want the pushrod stabilized as close to the top as I can get it. On some applications, it might depend on how far down the pushrod is hardened, another reason to use the raised plates. I also like Mr. Gasket 1075 studs.

Don't waste your money on roller tip rockers if they have the stock-type ball socket pivot arrangement at the stud. It's just another way to extract dough from your wallet for no gain. The difference will be made at the rocker pivot point. That's where you need a bearing. I still don't understand why someone with integrity hasn't stepped up to the plate with a roller bearing trunnion and non-roller tip. That would be the end-all in rocker design in my opinion.

I'm relying on information from Racer Brown, who set up high speed cameras and strobes to see how the currently-available roller tips operate. He said that the small diameter rollers at the tip have insufficient diameter to complete a mechanical couple and that they simply "skid" across the tip of the valve.

A properly set-up conventional stamped rocker will roll across the tip of the valve much in the same manner that the rail of a rocking chair rolls across the floor.

In my opinion, if you want the best roller rocker, buy Harland Sharp.

Also, in my opinion, use only stock ratio 1.5 rockers on any flat tappet hydraulic or flat tappet solid cam along with good oil additives, particularly with an "extreme" type of grind. The lobes on those cams are ground at the limit of mechanical feasibility, so any additional stress you introduce, like using 1.6 ratio rockers, is just asking for trouble. You might pick up somewhere between 5 and 15 additional hp with the increased ratio rockers, but you put the lobe/lifter interface at increased risk of failure.

[ericnova72]

TechInspector, Crane used to offer their aluminum body roller trunnion Gold Race rocker arm with a hard curved "shoe type" insert at the tip instead of a roller tip, but it didn't catch on. Last time I saw it advertised was about 10 years ago.

They also sold a gold arm that had a pushrod cup retained by a set screw, the cup was reversable to make either 1.5 or 1.6 ratios, but I havn't seen those advertised for about the same amount of time either. Don't know if both features were ever offered in the same set of arms.

[techinspector1]

Thanks Eric.