SBC 350, Small Solid Street cams

[CamKing]

I've read that until somewhere around 270ish, there's actually more area under the curve with a flat cam vs a roller. What say you?

I say, that's the dumbest thing I've read this week.

About the most lift you can get out of a 256 seat duration, using a ,842" flat tappet lifter is .300"
I've got a 256 solid street roller with .352" lift.
Which one do you think has more area.

[mikes]

Not trying to highjack this thread or step on any toes but I have a small sbc solid roller for sale, its even a small base circle if you ever want to go 383. Heres the link for the specs.

http://www.summitracing.com/parts/CRN-118571/

[pdq67]

I think he's talking about that a solid lifter cam can knock the lifter up faster than a solid roller cam can up to a 225 to a 230 at .050" duration or so cam, then the roller walks all over everything.

Cams, for more grunt, maybe CC's XS268S at 268/230/274/236, 110/106, .488"/.501" and need's the hot lash.

Middle of the road here, maybe CC's old 282S or a way old-school Isky Z-25 solid lifter cam for more topend.

All this depends on just how much "knarly" that you will put up with on the street.

My long gone Crippled Buddy that had an old '58 'Vette ragtop with a 375hp/327FI engine that had no more than an old Isky Z-50 and 2.5" x 6" long pipe nipple straight down dumps off his ramshorns, 4-speed, 3.8's and little-bitty 7.00/14 tires. I saw a new '65 Chevelle H/T 350hp/327, 4-speed, 3.73 reg car jump Tom outta the hole going into 3rd when he motored by the Chevelle still in 1st gear and Gene had to shift for him! Gene jerked right a 7,600 to maybe 8,000 rpm!!

And I rode shotgun with Tom late one Sat evening on a pin ta VO run to a little town 8 miles way. We came back and I looked over and he was running 7,200 rpm by his big Dixon tach. I asked him how fast we were going and he said between 160 and 170 mph because the MoSHP Intercepters couldn't catch him the last time he got in trouble and they chased him out of state at that rpm!

SOB was STILL pulling at 7,200 rpm, I couldn't believe it!!!

pdq67

[Dodge Freak]

Still pulling @ 7,200 in 3rd gear--and lasting long term--is where the short stroke motors shine. Sure longer strokes can work if U got the $ for aftermarket everything, even the block.

All the motor needs is the right heads and camshaft--and stable valve train.

I gotta get a better cam for my little guy.

[LilRacr]

Cams, for more grunt, maybe CC's XS268S at 268/230/274/236, 110/106, .488"/.501" and need's the hot lash.

I have looked at the Comp stuff, but I am looking at the Solid Roller stuff, I want to get all the lift I can get and still try to keep the overlap to minimum for mileage and low end power. I have the Vortec heads still going at .700 lift, so I have the SSR working to keep the air attached, now I need to get the port and valve job like I want it. The head should go 280-290 cfm when done around the .600 lift range.

I have always liked the solid cams, roller or flat tappet, but I have never tried to build an efficient high power motor, most of the time it's all about big power and loose converters, but this one I want to keep it civil for a nice 300 mile cruise on one tank of gas with the family and yet still get told I need a roll bar at the track.

Playing with different engine programs I should be able to make 475hp with a cam like Mike suggested. That should be plenty to get the car in the mid 11's at 118mph.

[CamKing]

I think he's talking about that a solid lifter cam can knock the lifter up faster than a solid roller cam can up to a 225 to a 230 at .050" duration or so cam, then the roller walks all over everything.

Again, false.
This isn't 1950 any more.

[randy331]

.
What I have SBC 350, 062 Vortec heads 2.02 valve (ported with correct cross section should end up about 190cc intake runner), efficient design.

Did you really grind 20+ cc out of an 062 casting head?
Where in the port did you take that much out?
Have they been on a flow bench, or is that 280-290 cfm estimated?
Will this engine see a dyno?

Randy

[Dodge Freak]

I think he's talking about that a solid lifter cam can knock the lifter up faster than a solid roller cam can up to a 225 to a 230 at .050" duration or so cam, then the roller walks all over everything.

Again, false.
This isn't 1950 any more.

Or 1980


Its 2010..make soon to be that 2011

[Matt Gruber]

there is an old vette on the street with a circle track solid cam!
said he got 18 mpg on a trip. runs strong.
catalog says: Broad power band. Short oval profile. Heavy car.
RPM 2000-6000 redline 7000+
238/244/107
seat 268/274
lift .497 .503
Not for Bobby, just posted in the interest of science
opinions ?

[LilRacr]

Did you really grind 20+ cc out of an 062 casting head?
Where in the port did you take that much out?
Have they been on a flow bench, or is that 280-290 cfm estimated?
Will this engine see a dyno?

Right now the heads are "in process" as I get a break from other work, so I hit them a little bit here and there. The heads are right around the 182-183cc mark right now and the flow is in the 270's at .550 lift with a small throat and still using the 1.94 valve and seat diameter. The Pushrod Pinch is in the 2.2" area and the short wall is pretty straight but a good 1/8" from the bolt hole. The last thing I worked with was the S.T. to keep the air attached, next I am going to get a 2.02 valve in there and finalize the throat/bowl area as that is faster than I would like it.

So no, I have not finished the port, but with the sonic tester I have room to work where I want to. It seems the thinnest spot on the heads are the short turn. But with larger valve area and correct throat and seat designs I should be able to easily get the port into the 280 range and "maybe" 290.

I have done several sets of the old 185cc GMPP Vortec heads ported to 200cc and 2.00 vavle they would go close to 300cfm at .600 or .650 lift. So I should be able to get these pretty close.

Also note these are my personal heads so I can afford to take extra time to really tweak on them, my limiting fastor is going to be the intake flow attached to the head, I may stop short of the extra flow if the intake seems to restrict it too much and I can't pick it up.

Is it cost effective to do this, probably not but I have the castings and not in a huge hurry to get the motor done.

The motor will not go on a dyno, but track testing will be done. I am willing to put an automatic and correct converter in the car if the Muncie can't handle the power. This is all going in my personal '65 Chevelle street car.

[LilRacr]

there is an old vette on the street with a circle track solid cam!
said he got 18 mpg on a trip. runs strong.
catalog says: Broad power band. Short oval profile. Heavy car.
RPM 2000-6000 redline 7000+
238/244/107
seat 268/274
lift .497 .503
Not for Bobby, just posted in the interest of science
opinions ?

Matt,

I debated the small solid flat tappets for a good while, but after I decided to port the heads I want to utlize the added power and flow of the roller. Not to mention, I am tired of being worried about the oils zinc properties needed to make the lobes last.

[Matt Gruber]

there is an old vette on the street with a circle track solid cam!
said he got 18 mpg on a trip. runs strong.
catalog says: Broad power band. Short oval profile. Heavy car.
RPM 2000-6000 redline 7000+
238/244/107
seat 268/274
lift .497 .503
Not for Bobby, just posted in the interest of science
opinions ?

Matt,

I debated the small solid flat tappets for a good while, but after I decided to port the heads I want to utlize the added power and flow of the roller. Not to mention, I am tired of being worried about the oils zinc properties needed to make the lobes last.[/quote]

Bobby
i debated should i put "not for Bobby" up top, or at the end. I figured it was a short post, and u would read the whole thing. i was wrong. The post topic title SMALL STREET SOID CAMS will surely be read by many in the future, and i wanted to give those readers some more options.

[LilRacr]

Matt,

I read that....

My many prior experiances with solid flat tappets is why I am going with such a small solid roller. I figured what better way to make good power at 6500 rpm and still get away with something fairly small than to do a solid, not to mention you don't have to deal with the worry of lifter bleed down at high rpm. I know many have done a hyd cam and spin it to 7k, but many also lose power that they don't even know about while the cam should still be making power. Thats not something I want to worry about.

[CGT]

Right now the heads are "in process" as I get a break from other work, so I hit them a little bit here and there. The heads are right around the 182-183cc mark right now and the flow is in the 270's at .550 lift with a small throat and still using the 1.94 valve and seat diameter. The Pushrod Pinch is in the 2.2" area and the short wall is pretty straight but a good 1/8" from the bolt hole. The last thing I worked with was the S.T. to keep the air attached, next I am going to get a 2.02 valve in there and finalize the throat/bowl area as that is faster than I would like it.

So no, I have not finished the port, but with the sonic tester I have room to work where I want to. It seems the thinnest spot on the heads are the short turn. But with larger valve area and correct throat and seat designs I should be able to easily get the port into the 280 range and "maybe" 290.

I have done several sets of the old 185cc GMPP Vortec heads ported to 200cc and 2.00 vavle they would go close to 300cfm at .600 or .650 lift. So I should be able to get these pretty close.

Impressive! What type of bench do you use for testing your work?

[LilRacr]

Impressive! What type of bench do you use for testing your work?

The bench I use is an older SF300, it's in line with ports and information I have gotten from other consevative (non inflated)benches.

I would never get this in depth with a customers head unless there were rules attached, I would have started with a different head, but I had the castings and the means to do all the work, so we will see how they work in the end.