Rhoads Variable Lifters. . .Auto-X/Road Racing???

[atomicjoe23]

Has anyone used Rhoads Variable lifters for Auto-X or Road Racing???

Thoughts, experiences???

I've got a '67 Firebird with a 400 that I'm doing some top end upgrades too and just read about these in the "Building Max Performance Pontiac Engines" book. . .that book is geared towards drag racing so I was wondering if they would be beneficial for Auto-X or Road racing. . .sounds like they might be.

Thanks for the help!

[Vegas69]

My gut tells me no. Drag racing lasts 15 seconds. Road racing lasts 20 minutes. I wouldn't want them in a sustained high rpm application.

[Panteracer]

Used them on several autocross motors... seemed to do ok
I think the new roller lifters are a better thing now

I would also look at what pan you have as I have had
no luck with any that say it is a road race style
Accumlator is the only way I am able to keep the oil
pressure up in a Pontiac motor while hitting the turns hard
Spun many a bearing in the Pontiacs in the past

Bob with an MR-1 494 CV-1 headed Pontiac now

[atomicjoe23]

Thanks Panteracer. . .I heard back from Jack Rhoads as well and he said they are successfully used in auto-X and road racing applications. . .

[GregWeld]

I don't understand why you'd want to use these. Today's roller cams offer so much more power and drivability. The need for Rhoad's lifters as a bandaid for too much cam on the street is so "yesterday".

[atomicjoe23]

That's why I'm asking GregWeld. . .trying to figure out what is out there and current for Pontiac engines for this type of application. . .

[GregWeld]

Originally Posted by atomicjoe23

That's why I'm asking GregWeld. . .trying to figure out what is out there and current for Pontiac engines for this type of application. . .

I totally get it.... and it's a very good question. I looked into them years ago when big street cams were de rigueur. I should have looked at my response so that it didn't sound like I was saying WTF are you thinking! I didn't mean it that way --- I was really just saying that these days with the right roller cam - you can make crazy power and be totally streetable. This is something that wasn't possible to do back when the Rhoads lifters were invented.

[Ron Sutton]

I agree with Greg.

I ran Rhoads lifters back in the 70's & 80's on street engines we built to build a wider powerband into the engine. The lifter low-rpm bleed off allowed you to run a bigger duration cam. At Idle, the lifters bleed off so much, the engine effectively had much less cam duration. This bleed off reduced as you revved the engine up to 3000 RPM & after that acted just like a regular hydraulic lifter ... so the bigger duration built more power up top. They worked very well & were a nice little trick to broaden the powerband.

Technology today has surpassed that. The hydraulic roller lifters allow for much steeper camshaft ramp angles than can be run with conventional "Flat/Sharp Edge" solid or hydraulic lifters. So now, the duration can be small for bottom end ... but the steeper ramps allow for much more area under the lift curve ... so more power in the mid to upper RPM range ... even with shorter duration numbers.

You could say both of these strategies do the same thing, but different ways. But in reality, the gains from the hydraulic roller lifter far outweigh the gains from the Rhoads variable duration hydraulic lifter.



.

[atomicjoe23]

So are hydraulic roller lifters an option then. . .I thought that Pontiac engines required modifications to run roller lifters. . .

. . .I just finished reading "How to Build Max-Performance Pontiac V-8's" and they didn't recommend hydraulic roller lifters for Pontiac engines. . .granted that book is more focused on drag racing, but it does talk about balanced, streetable performance.

If hydraulic roller lifters are an option what lifters and cam would you guys recommend for a mild 400 (at the moment anyway, I would like to increase the displacement with an upgraded rotating assembly after I get the suspension/brakes where I want them).

Thanks for the help!

[Ron Sutton]

What cylinder heads do you have?