Suggestions For Next Drag Strip Testing Day

[Cliff Ruggles]

The excellent iron manifolds only add weight, they don't slow them down.

I have customers running in FAST well into the 10's with "D" port heads and "log" manifolds on them.

The Pontiac HO and Super Duty 455's are "sleeping giants".  They are just sitting there waiting for someone to squeeze them a little harder (tight quench and raising the compression a tad) and the right cam to unlock the power.

I've ran several different cams in them and dyno'd each one.  The 281/287, 230/236, 112 HR was the smallest one and a little disappointing.  Done at 5200rpm's even though it made 1hp/CID it was too "mild".

I have another cam with bigger .361" lobes that specs at 284/296, 230/242, 112LSA that makes another 20hp and at least 20ft lbs but still pretty "mild".

I really like going up to 236/242 or 236/245 and pushing them out on a 114LSA with the ICL at 110.  This pushes them over 500hp with ease and gives up NOTHING from idle to the shift point over a small cam on a tighter LSA.

Look at the dyno chart closely, especially up around 4800-5200rpms.  A small cam is DONE way before that where the larger cam is making more torque up there than the smaller one made in the mid-range!  Even if you shift at 5000rpm's the car will run nearly a second quicker in the 1/4 mile with the larger cam in it as it makes a LOT more average power, and power from where the converter stalls to the shift point.

HO Racing pushed many of their cams out on a wide LSA and so did Nunzi, maybe they knew something that most folks don't these days.......

[Brian B.]

Cliff...you've given me great tips throughout this thread.  I really appreciate your time and the depth to which you went to help.  I saw some you made some early morning posts too.  We're fortunate to have you as a resource and your firsthand experience to utilize.  Thank you!

[Cliff Ruggles]

You are most welcome. 

One of my goals is to help customers obtain the best performance possible from their combination. 

I still remember my first track outing with the Ventura decades ago in Richmond VA.  At that time it was powered by a 400 engine with 6X heads and about 7.7 to 1 compression.  The cam was a Crower 60240, 210/221/112LSA.  Backed by a TH400 with a stock converter and 2.73 gears it still managed 14.0-14.20's at 98-100mph. 

I was able to "tweak" that combo to a best of 13.87 @ 101mph.  Since then I've powered the car with two different 428 engines and two different 455 engines.  Each engine was a step up in power and required changes behind it to effectively use the power.  I've had 3.23, 3.42 and 3.73 gears in the rear as well.

The first 455 was pretty "basic", just nicely cleaned up 6X heads, 9.97 to 1 compression, Crower RAIV cam, Rhoads lifters, and 1.73 ratio rocker arms.  That engine was AMAZING and very difficult to hold on the starting line.  After busting up a driveshaft, a transmission, two diff's and testing a half dozen different types of tires I managed to get it to run into the high 12's at 107-108mph.  Two more seasons tweaking the suspension, welding in sub-frame connectors and wham went right to mid-12's at 108-109mph.  It still felt a little "soft" past 5000rpms but rock solid otherwise, and running solidly in the 12.40-12.60's with a best of 12.37 @ 110mph.

Over one Winter I upgraded the fuel system, sumped the tank, 140gph pump behind the tank and 8AN lines/fittings everywhere.  The first two runs with the new fuel system was 12.10/12.11 @ 112mph!  I actually over-revved the engine as it spun past my 5500rpm's shift point and on past 6000rpm's so quick I didn't move the shifter fast enough!  I caught on quickly and the next runs were 12.02, 12.03 @ 112mph shifting at 5500rpm's. 

That was a solid .3-.4 seconds and 2-3 mph improvement over the previous set-up.  I had no idea at that time that I wasn't keeping up with the engine.  I had even tried (on the advice of many non-believers) running a Holley 850dp carb and with the old fuel system it ran no quicker than the Q-jet.  That pretty much debunked the myth about not having enough fuel bowl capacity, you are either keeping up or you aren't.

Anyhow, made some more changes and right into the 11's we went.  I continued to exploit that 455 and got hooked up with KRE to test their new aluminum heads.  That made HPP and Popular Hot Roddings Engine Masters edition and the car ran in the 11.60-11.80 range for several more years with a best every 11.52 @ 116mph. 

In 2009 I built a 428 with a 4.21" stroke crank topped with CNC ported KRE heads and it's still in the car.  It's WAY too quick for 1/4 mile tracks (runs under the roll bar rule) but typically good for 7.20-7.25 @ 95-97mph in the 1/8th mile.  On 1/4 mile track I add 200lbs in the truck, retard the timing 4 degrees and short-shift at 5000rpm's and that usually keeps the officials from visiting my pit-sight and giving me my walking papers!

....continued

[Cliff Ruggles]

The learning curve with the Ventura (I also help out with 4 other cars raced out of the shop) has been a long one and I've tested just about EVERYTHING that's out there.  This includes distributors, intakes, all sorts of spacers, air cleaners, exhaust systems, mufflers, and scores of carburetors.  I've also tested some camshafts, hydraulic flat tappet, solid flat tappet, and hydraulic roller, camshaft timing, and a truck load of converters, plus at least 6 different types of tires.

I also dyno'd just about every engine we built here, and have a nice learning curve from the dyno as well.  So if anyone has any questions don't hesitate to ask, but I'll warn you that I don't hold back when it comes to giving advice.  There are a LOT of parts out there that don't make the grade, TONS of "propaganda" to go with it, and folks have vested considerable money in some of it.  So wear your big boy panties if you are wanting me to give straight advice based on direct testing with parts you may be using........Cliff

[tayto]

Cliff do you still use and recommend Rhoads lifters? I've heard good things, and was thinking about trying them in my  roller SBC one day.

[Cliff Ruggles]

I always use Rhoads on flat tappet camshafts as there are no negatives anyplace.

With the right cam you cam mimic the power of a very well chose Hydraulic Roller cam at much less cost.

I did a back to back dyno test on my last 455 engine between a 304/314, 231/240, 113LSA cam and a Comp HR cam with 284/296, 230/242, 112 specs.  The roller cam had .361" lobes and a LOT more lift than the flat cam. 

The roller cam only made 3hp/4ft lbs more power than the flat cam and done at 5400rpms where the flat cam made peak power at 5600rpms.

At the track the roller cam was worth more than the dyno showed, running about a tenth or so quicker for most runs and a solid 2mph faster.

Best run ever with the flat cam was 11.64 @ 116mph.  The roller cam went 11.52 @ 118mph.

What the Rhoads lifter do is allow us to use a relatively large cam with less negatives, and have a variable valve timing set-up in an older engine design. 

I've back to back tested them on the dyno against HT-951-R lifters and there is no power loss whatsoever from the fast bleed design.......Cliff