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

[xb-60]

Originally Posted by Jerry Clayton

I don't think you can tell the differance in the way the 289/302s rev --there is.019 differance in the stroke and both have the 4.0 bore

A late 302 roller block would be my preferance if I was building a 302 for myself, however if I was building a short deck sbf I would use the Dart block and most likely in aluminmu.

Jerry, the stroke on a 302 is around 0.130" longer than a 289; not much, so all other things being 'equal', they should both have the potential to rev nicely with such a short stroke (2.87" and 3" for the 302)
While looking up these figures, I checked on the bhp and torque figures for both...
289 K 271bhp @ 6000 and 312lb/ft @ 3400
289 A 225bhp @ 4800 and 305lb/ft @ 3200
302 GT350 250bhp @ 4800 and 310lb/ft @ 2800
Agreed, bare figures don't show the shape of the power and torque curves, so you can't assume from these figures that the 289 A and the 302 GT350 with power peaks at 4800 would be real slugs at anything higher than 5000.
So what do these figures prove? ....er, nothing really. But logic tells me that stroking to 331 or 347 would produce an engine that's less happy at higher revs. But more powerful, yes.
Cheers,
Glen

[zrayr]

Originally Posted by xb-60

"............ I checked on the bhp and torque figures for both...
289 K 271bhp @ 6000 and 312lb/ft @ 3400
289 A 225bhp @ 4800 and 305lb/ft @ 3200
302 GT350 250bhp @ 4800 and 310lb/ft @ 2800
Agreed, bare figures don't show the shape of the power and torque curves, so you can't assume from these figures that the 289 A and the 302 GT350 with power peaks at 4800 would be real slugs at anything higher than 5000.
So what do these figures prove? ..........."
Glen

remember, the A code 289 didn't have screw-in studs for the rocker arms like the K code engines did, so it couldn't hold the heavier valve springs needed to rev (the studs would pull out of the heads at high rpm). By the time the 302 based GT-350 came on the scene (1968) emission regulations were in place and the engine was de-tuned.

there were bottom end differences between the A code & K code 289's as well that enabled the K code to be a fun little rev happy machine with decent reliability,

Z.

[xb-60]

Z, I included the 289 A code as I assume that there would be more of them around than the K code.
Cheers,
Glen

[LightNFast]

............................

[zrayr]

Originally Posted by LightNFast

".......I wonder how many people believe Shelby’s race prepped 289’s were actually a 289? It was a lot easier to snow people back then...

the sore loser Corvette crowd were on the race officials to keep things pretty "honest" in the Cobra/Mustang camp. Once the Cobras tried to race with an oil cooler. Corvette racers complained, saying it was "modified" and not eligible to run in the stock class. So the Cobra's oil coolers were disconnected, and still won the race. Using Corvette's logic against them, Shelby has the oil coolers re-connected, and ran the same cars in the modified class, and won that one as well.

Not to say there wasn't some "creativity" shenanigans goings-on in both camps. And once the Cobra were overseas racing against Ferrari, the scrutiny became even more political.

Z.

[blykins]

Originally Posted by xb-60

But logic tells me that stroking to 331 or 347 would produce an engine that's less happy at higher revs. But more powerful, yes.
Cheers,
Glen

That's a pretty common misconception....a longer stroked engine can pull the rpms just like a short stroke engine. I have 4.100" stroke 445W's pulling over 6500, as well as 4.300" stroke Boss 9 engines pulling 6500 rpms.

I have a customer that runs the 7.50 1/8th mile class. The 347 that I did for him gets shifted at 7000.

[xb-60]

Originally Posted by blykins

That's a pretty common misconception....a longer stroked engine can pull the rpms just like a short stroke engine. I have 4.100" stroke 445W's pulling over 6500, as well as 4.300" stroke Boss 9 engines pulling 6500 rpms.

I have a customer that runs the 7.50 1/8th mile class. The 347 that I did for him gets shifted at 7000.

Let me re-phrase the question...logic tells me that stroking a 302 to 331 or 347, or a 351W out to 445 would require significant spend on the rotating assembly to make them as happy at 6500 as a standard stroke engine, yes?
Re-phrasing further, what spend would be required to make a 347 safe at 7000, and a 445W safe at 6500?
I like this friendly banter, Brent. Keep it coming!
Cheers,
Glen

[blykins]

"Re-phrasing further, what spend would be required to make a 347 safe at 7000, and a 445W safe at 6500?"

The same parts that would make a 289/302 safe at 7000.

Just because it's a shorter stroke, like a factory 289 or 302, it doesn't mean that it will automatically live endlessly at 7000 rpm. I wouldn't build a 302 to make power at those rpm levels without a quality aftermarket crank, rods, light forged pistons, shaft mounted rockers (or at least stud rockers with a girdle), etc, etc. The 445W automatically gets most of those parts as the SVO blocks use the 2.750" forged crankshafts, aftermarket rods, etc.

But there again, we're losing sight of the original agenda....a 7000 rpm engine doesn't match to a 3.07 rearend gear in a street car.

[zrayr]

Originally Posted by blykins

That's a pretty common misconception....a longer stroked engine can pull the rpms just like a short stroke engine. I have 4.100" stroke 445W's pulling over 6500, as well as 4.300" stroke Boss 9 engines pulling 6500 rpms.

I have a customer that runs the 7.50 1/8th mile class. The 347 that I did for him gets shifted at 7000.

in the narrow scope of this discussion, using stroked SBF engines as examples, you are essentially correct. As you say, a 289 stroked to 331, etc, will rev to 7,000 or more. Bit I still maintain that shorter stoke engines will hit the red line quicker if the overall displacement is more or less equal.

In the long run, long stroke engines just can't compete with over-square engines in a maximum rpm context. Valve size is the one major limitation in small bore/long stroke engines, but excessive piston speed (measured in ft traved per minute at maximum rpm) cannot be ignored.

That said, for example I am much more happy riding the long stroke 650cc Triumph vs. the short stroke 650cc BSA.

Z.

[blykins]

Originally Posted by zrayr

to the degree we are talking about, stroked SBF engines, you are correct. However long stroke engines just can't compete with over-square engines. Valve size is the one major limitation in small bore engines, but excessive piston speed (measured in ft traved per minute at maximum rpm) cannot be ignored.

Z.

Try to explain that to the pulling truck guys running 557ci BBF's (4.420" bore, 4.500" stroke) turning 8000 rpms....

There are lots of spoken generalities with engines that are not always the case.

[zrayr]

Originally Posted by blykins

Try to explain that to the pulling truck guys running 557ci BBF's (4.420" bore, 4.500" stroke) turning 8000 rpms....

There are lots of spoken generalities with engines that are not always the case.

I just edited my last post to include, "...That said, for example I am much more happy riding the long stroke 650cc Triumph vs. the short stroke 650cc BSA..."

which is exactly the same as the example you provided. ha ha. Especially on the dirt track , the long stroke, high torque Triumphs ruled. Lower torque, higher rpm machines consistently ate their dust & finished out of the running

Z.

[DAVID GAGNARD]

Thanks David, for more of the real world comments.
Can you tell me why you decided on flat tappets?
Cheers,

Because back in the mid 90's when I built this engine, it was to be a street cruiser/show car/sunday driver and I was dirt poor and the camshaft with lifters from SUMMIT at that time was about $79.00!!!!!!!!!!!!!!

Every street engine I've built for myself since has gotten a hydraulic roller camshaft....
My race engine uses a solid lifter,roller camshaft.......

The hydraulic roller camshafts just have so much more to offer,it's a no-brainer for me...

David

[xb-60]

Originally Posted by zrayr

to the degree we are talking about, stroked SBF engines, you are correct. However long stroke engines just can't compete with over-square engines. Valve size is the one major limitation in small bore engines, but excessive piston speed (measured in ft traved per minute at maximum rpm) cannot be ignored.

Z.

Yes, surely the maximum piston speed on a 347 with a ....3.4"? ...stroke must be a lot higher than a 2.7" or 3" stroke engine? That's got to make a difference in the cost of the bottom end
Cheers,
Glen

[Gaz64]

Originally Posted by xb-60

Yes, surely the maximum piston speed on a 347 with a ....3.4"? ...stroke must be a lot higher than a 2.7" or 3" stroke engine? That's got to make a difference in the cost of the bottom end
Cheers,
Glen

Very true Glen, and yes you do have to spend money the larger you go, but there are engines out there with 5 1/4 inch strokes or more that spin to 8000 rpm.
For example: John Kaase Racing Engines.

As others have said, if you have a choice, go for a milder package with more cubes, much better combination.