Valve lifters…solid/hydraulic/roller tappet/flat tappet?

[LightNFast]

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[xb-60]

Originally Posted by LightNFast

Glen,

Shelby’s 289 “High-Rev” Cobra engines were rollers and produced about 390HP @ 7000. So even back in the 60’s they knew it was better to roll…

Kurt,
Yes I’ve read a few old tests where rev limits of 7000 or even higher were mentioned for 289s. These were probably accompanied by grumpiness at lower revs, but that being almost 50 years ago, I’m assuming that developments in cams / heads / carburation / fuel injection has made available better compromises.
One of my other cars is a mid-seventies Alfa twin cam (unmodified) with side draft Webers. This engine has stacks of grunt from not far above idle, and at the 6000 redline, it feels like it wants to keep going forever. My daily driver, an Australian built ‘cooking’ V6, is redlined at 6200, sees the redline at least once a day and loves it. That’s what I want in a 302.
Cheers,
Glen

[zrayr]

Originally Posted by xb-60

Kurt,
Yes I’ve read a few old tests where rev limits of 7000 or even higher were mentioned for 289s. These were probably accompanied by grumpiness at lower revs, but that being almost 50 years ago,........."
Glen

I routinely shift at 6,500 to 7,000 rpm. The engine is an essentially stock 289 Hi-Po K code. It is a flat tappet engine, with a stock Hi-Po cam. There is no grumpiness at any rpm, idles fine at 900 and is smooth to 7,000+ rpm. In a nine year time span I've got over 45,000 miles on the engine. Seems very durable to me. With good lubrication, meaning an oil with plenty of zinc, there are no issues with cam or lifter wear. Been using Mobil 1 15w-50 the entire 9 years.

Z.

[xb-60]

Originally Posted by zrayr

I routinely shift at 6,500 to 7,000 rpm. The engine is an essentially stock 289 Hi-Po K code. It is a flat tappet engine, with a stock Hi-Po cam. There is no grumpiness at any rpm, idles fine at 900 and is smooth to 7,000+ rpm. In a nine year time span I've got over 45,000 miles on the engine. Seems very durable to me. With good lubrication, meaning an oil with plenty of zinc, there are no issues with cam or lifter wear. Been using Mobil 1 15w-50 the entire 9 years.

Z.

Z - can I buy your engine?

Brent - what is different here that enables this engine to do what Z describes, and do what I want an engine to do?
The way I see it, if I want an engine that revs (but behaves at low revs as well) I need to start with a smallish engine, use good (light, balanced) gear for the rotating bits, and not go 'I need more power/more cubes'.
But I'm definitely not the expert here, so tell me where I'm going wrong in my thinking.
Cheers!
Glen

[zrayr]

Originally Posted by xb-60

Z - can I buy your engine? ........"
Cheers!
Glen

ha ha. yes you can, for 115K, & I'll include the rest of the car no charge.

Seriously though, a stock 289 K code engine that has been balanced properly is a great little engine. With some improvements to the breathing, like a good set of AFR heads, or a vintage Paxton (as I have), then 350+ HP can be expected. Or you can stroke it to 331 or so if you like strokers. However I like the way the short stoke (289) engine revs quickly, so stroking is out for me.

Z.

[blykins]

Originally Posted by xb-60

Z - can I buy your engine?

Brent - what is different here that enables this engine to do what Z describes, and do what I want an engine to do?
The way I see it, if I want an engine that revs (but behaves at low revs as well) I need to start with a smallish engine, use good (light, balanced) gear for the rotating bits, and not go 'I need more power/more cubes'.
But I'm definitely not the expert here, so tell me where I'm going wrong in my thinking.
Cheers!
Glen

A stock K code 289 was rated for peak horsepower at 6000 rpm. Why shift at 7000? As I mentioned earlier, an engine with a lower peak will have better manners down low and more power available down low.

All of this makes a huge difference.

BTW Z, I was just offering that question up for thought in general, I wasn't directing it at you.

[xb-60]

Originally Posted by blykins

A stock K code 289 was rated for peak horsepower at 6000 rpm. Why shift at 7000? As I mentioned earlier, an engine with a lower peak will have better manners down low and more power available down low.

Why shift at 7000? Just been reading 'Shelby Cobra Gold Portfolio" with road test data from R & T, Sept 1962. The 260 engine in that first Cobra is rated at 260bhp at 5800 rpm, but I've seen the same bhp figure at 6500 in the same compilation. The interesting thing though is the maximum speeds and revs quoted:
4th...153mph at 7000rpm
3rd...112 at 7200
2nd...89 at 7200
1st... 67 at 7200
Why not shift at 7000 if the little rocket will pull those revs in top gear!
OK, admittedly this was a 'Press' car, and it's paper figures would not match its actual figures, but this is 1962, remember, and these figures are sensational! Can we not have this rev-ability and apparent mild enough temperament now?
Cheers!
Glen

[blykins]

You answered your own question. The engine that was shifted at 7200 wasn't the same engine that peaked at 5800. If it was, then I say shame on the drivers as they apparently had no clue on how to drive. Did they mention how the car ran at 1200 rpm while driving downtown? Or how well it took off on a hill with a 3.07 rearend?

You seem to be pretty adamant about what you want, so I say build it however makes you happy.

However, remember that you posted to get opinions. I have given you opinions plus a great amount of real world data.

[zrayr]

Originally Posted by blykins

A stock K code 289 was rated for peak horsepower at 6000 rpm. Why shift at 7000? .........."

My exact post was "....The engine is an essentially stock 289 Hi-Po K code..."

It's not EXACTLY stock, but essentially stock. I should have posted the differences. It does breathe a bit better, and I suppose that is why it is still pulling strong to 7000+ rpm. I had it dynoed years ago, but don't recall the exact peak numbers. I do remember that the operator was wanting me to OK a higher testing rpm than the 6,800 I had authorized, as the engine had not dropped off in power yet at that level.

I have slightly bigger valves, a mild head porting job, Crane Cams gold series aluminum roller rocker arms, a 2.5" MagnaFlo stainless steel exhaust system, a msd digital 6 ignition, a high volume Melling oil pump w/ a Melling oil pump shaft, and a vintage Paxton supercharger.

The intake & headers are the Shelby supplied items (Cobra lettered hi-rise intake & tri-y headers). The bottom end is stock.

Z.