Big sft cam
 

Kicking around the idea of running a big sft cam instead of my SR. How big of sft have you guys run ?
My SR has .431 lobe, .265-.264 on a 112.
How close could I get to the power level of my Bullet SR cam ?
Reason being is I just bracket race so max power is not the most important thing. I would think it would be very hard to split a 400 block with all the good stuff(solayed caps, filled ect)
Doubt you could make over 700 HP NA on pump gas. Don't have to worry about any needle bearings flying around or a lifter bar breaking and going sideways either. Could be a tough, reliable combo.
Should be able to make 650 HP with my 350cfm High Ports you would think.
Would have to deal with the break in too.

Are we taking running high compression, like over 11.5 with 400 cid or high compression stroker 400?

If your talking even just 325 cfm of intake flow @28” at .650” lift , then yes even a solid lifter 406 cid motor will make you 650 hp while not forcing you to spin it to over 7500.

A related tidbit....

Ken Crocie did a 455 pump gas engine build featured in Pontiac Enthusiast magazine that used a Comp Cams 320H hyd flat tappet cam with 268 degrees intake duration at .050", Rhodes lifters and Harland Sharp 1.65 rockers.
It netted an actual 0.606-inch lift 'at the valve'.

Here is an interesting comment from Ken from the article....

"If you examine the actual lift curve at the valves, a modern quick-lift hydraulic cam, in conjunction with high-ratio rockers and Rhodes Vari-Duration lifters, will approximate the valve-lift curve of a traditional solid roller up to about 0.600" lift. Over about 0.650" valve lift, the big-nose solid roller is king."


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For reference, I went SFT on the 482 road race engine for old school ruggedness. Crower lifters, followed Mike's break-in procedure (no inner springs, 2500 rpm, etc).

Ultradyne lobes from Bullet
259/267 @ .050"
292/301 @ .020"
.3677 lobe lift
108 deg lobe separation (Tim wanted more but he reground my existing cam and there wasn't enough meat to get there)
1.65 rockers
Hi-port 330 cfm heads
1150 Dominator

601 hp @ 6000 rpm. Still making 590 @6500 rpm
617 ft-lbs of torque @ 4400 rpm
Started dyno pulls at 3500 rpm and it was already making 590 ft-lbs
Out on our back roads, traction in 1st gear (2.43 x 3.50) with road race tires is almost non-existent. 2nd gear....hang on!!
Doesn't like to idle below 1000 rpm. 1500 makes it happy.
I don't know or care about vacuum since I converted to manual Wilwood brakes.

FWIW,
Eric

11.5-1 461 stroker.
A 400 that makes 650 HP, sft under 7500 RPM, never heard of one. Bet that would be difficult for sure.
Maybe on paper. I do not even see the point of trying it with a 400 when you can just stroke it.

I have an iron headed pump gas 10:1 455 using a 256/[email protected]” SFT with 1.8s it is .612” lift. I helped someone on PY a few years ago that had the next step bigger 264/[email protected]” 112 LSA with 1.65s in a 12:1 455 with SM heads with some light port work trying to run 93 octane. I don’t know how he got along with it though, he wanted to drive the car to the track 90 plus miles and run 10s in a nostalgia super stock tribute. . I know of a 11:1 455 with a SFT that had .050” durations in the lower 270*@ .050”, I think it had a 108 LSA, as I recall it was a 3500 lb car running upper 10s with some pretty stock looking 16 d port heads. I recall looking at the head ports and wondering how the car was so quick.

The biggest SFT cam i have is 280*/284* @.050” on a 107 LSA with .397”/.4” lobes, with 1.8s it would be well over .70” lift. Would not be a pump gas cam, I would do some things differently on a pump gas direction. We have found that most times the SFT cam can be quite a bit bigger on it durations than a roller cam because most SFT cams have more acceleration off the seat and it trims up the overlap a lot. Several times we have went with a bigger SFT cam and were surprised how mild the cam sounded. I don’t see why a 350 cfm headed pump gas engine couldn’t break 700 HP, probably would take a lot of converter to make it work though.

I told Tim Goolsby at Bullet that I wanted at least 600 hp with a broad flat torque curve so I didn't have to always be shifting. I got EXACTLY what I wanted. Tim is at PRI every year (although I have verified for this year yet). It's worth the trip to talk to him in person.

Eric

Years ago I pieced together a SFT motor that I drove around for a few months and raced once. It was a .037 over 455, mildly ported RAIV heads, 11.3 compression, Warrior and a 1050. The cam was 275, 107 LSA and .600 lift. That motor was surprisingly drivable and ran great. It went 10.7 @ 124 with little tuning in a 3860 lbs Firebird with full exhaust. It drove milder than a solid roller with equivalent duration.

Art Peterson won a Championship using a SFT camshaft.

Paul, what class did Paul run in ?

Why is it that you don’t seem to understand that HP production is totally independent of CID.?

A 13 to 1 412 CID motor built right and spun up to 7500 to 7800 rpm will make an easy 650 hp, period, period!

If you don’t have the CID and or stroke to make 590 ft lbs at 6400 rpm then you simply spin the motor faster to produce that torque.

Torque X Rpm / 5252 = HP, not CID X Torque X rpm.

Decades ago a buddy’s 408 CID ( small block )Mopar with even back then out dated Brodix heads that I ported up to 315 cfm was making close to 700 HP at 8200 rpm, and it didn’t even have a Dominator on it, and yes with a SFT cam with high ratio rockers .

There are tons of 383 SBC motors making 650 with 18 degree heads and ever heads with a stock type 23 degree valve inclination angle.

So are you going to tell me you don’t believe that either?

Art ran in super stock with a .060” over 400.

I am not saying to not go for as large a CID that your wallet and car can handle, just that smaller CID motors should not be over looked .

The UD SFT 288/292, 255/259 @ 0.050 I used for awhile in my RAIV 400 pulled to 7000 but had no bottom end. It made only about 9" vacuum at idle.

Stop putting words in other peoples mouth. Never said I did not believe anything. I am sure it could be done, no builds came to mind. And making 650-700 HP with a pump gas 400, sft would in no way be easy. Actually nuts for a regular guy to try it. High RPM racing a Pontiac is high dollar racing.
\You can not even get a good crank for a 400. Cast or some POS cross-drilled Ohio. Super loose converter, always checking valve springs, changing braking system....... nope.
There is zero point on trying to compare any true small block engine with whatever cfm head to a Pontiac. They have light valvetrain, short decks, light cranks and rods ect, not comparable. Different worlds.
And the old, this cfm head gets you this much power deal. A engine does not run like a flow bench, one continuous pull. Engines have a intake valve slamming open and closing super fast and a pulse going back up that intake port every single cycle. Not the same thing.
Many times higher cfm heads have been out ran by lower cfm heads. Does it matter, yes and no IMO.
I asked a simple question, got some good real world examples of sft cam engines that actually existed. Not theory and spin it to the moon.
It sounds like it could be done with my engine but would have to go to manual brakes and buy a converter and good ones are VERY expensive these days.

A very wise engine builder named Joe Sherman told me years ago,HP is in the heads.Start there.Tom

The version of that told to me by Joe Mondello and Colin Myers is: "relibility comes from the short block, Horsepower comes from the heads". Words I live by.

When it comes to porting the factory Pontiac heads, H-O Enterprises' Ken Crocie, a recognized Pontiac expert, says "You can't make a Pontiac head big enough. You can make it wrong, but not too big."

Ahhh... but remember the "intake runner volume" controversy when the Edelbrock head first came out :)


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I remember one smart guy saying there's no replacement for displacement..... Or maybe it was "build the biggest engine you can"

Art, yep Paul.......... Art ?

The is little point in building a small ci Pontiac. Pontiacs are kind of weird. Our small engines well........ suck . No 326-350 will , ever, ever run like a small block Chevy, Ford, Mopar or LS.
We have one hand tied behind our backs and more cubic inches helps even it out. Even then, everyone else has a bigger bore for the same ci
Give me a 428, 455, 461, 505 and my next engine is going to be a 540 baby.
Got to try out this aftermarket block Pontiac stuff at least once.

You guys should be carefull and stop talking about Solid flat tappets and how great they can be...

...Or you will wake up the "Hyd. Roller for everything" police of this forum 🤣🤣...

Peter.

For me solids or nothing.

One of the key things in terms of cam’s and race motor power is how much duration you have at .200” lift and a SFT cam can have more then a roller at times while getting to that lift point faster .

Super Stock

Agree! I think flat tappet cams are great until the lobes or lifters get worn down and ruin the engine. I also think roller cams are great until a lifter fails and and the roller wheel/bearings go through the engine and destroy everything and break out the lifter bore. Just don't think there is an absolutely clear winner here. Some good luck and Karma must be involved. I am currently running a 251-259 Ultradyne SFT grind in my street car. I have 3500 miles on it now and 40+ dyno pulls on it. I have not had a valve cover off since it left the dyno about 3 years ago. Valvetrain sounds quiet, even and smooth. Doesn't mean it won't flatten a lobe the next time I drive it which will be tomorrow. But trending the right direction. Love the way a properly adjusted SFT cam sounds through a full exhaust system.

Mike did you have the cam Nitrided? .... What lifters are you using?

Same questions for Eric's cam if you don't mind sharing?

The cams we are using don't have any special treatment that I know of. Tim Goolsby @ Ultradyne said they verify the hardness depth somehow. Sorry I don't have any other detail. My cam core was new and Eric's was a re-grind because they just didn't have any cores. We are both using Crower cam saver lifters with the little EDM hole in the foot for additional oiling. All 16 lifter holes restricted to .035"-.040" oil holes if I remember correctly. Get lots of oil through those little holes. I use the little distributor oil hole in the rear plug as well.

So I have ran 2 sft in Pontiacs and everything went well. Still have a nice Crower .254ish sft on a 108. Lifters in order. But..... since it was the 80s and real Pontiac solid lifters were simply not available they are Chevy lifters. Dan Whitmore sold me the stuff. Said it just takes a longer pushrod, still have those too.
So I know it works. Tool steel lifters are available for Chevies and not too expensive.
Can those tool steel lifters and a nitrided cam help out reliability ?
Even if one had to do the lifter bore trick where you take a small round stone on a die grinder and make a small depression moving the oil hole up or down to better line up with the lifter band on the non Pontiac lifter.
Can it help ?