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Small cams on 106-108 LSA’s

General engine tech -- Drag Racing to Circle Track

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prairiehotrodder
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Re: Small cams on 106-108 LSA’s

Post by prairiehotrodder »

I've built 3 or 4 chevy small blocks with the smallest comp thumper cam. I am very happy with it.

For a fun, reliable 350 i use the Edelbrock E-street heads, flat top pistons, RPM air gap intake, 750 Vacuum holley and the above mentioned cam.
Its on a 107 LSA.

Brian

EDIT: i have also done the same motor but with vortec heads and edelbrock performer EPS vortec intake. It worked well also.
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Re: Small cams on 106-108 LSA’s

Post by CamKing »

prairiehotrodder wrote: Thu Nov 19, 2020 12:32 pm I've built 3 or 4 chevy small blocks with the smallest comp thumper cam. I am very happy with it.

For a fun, reliable 350 i use the Edelbrock E-street heads, flat top pistons, RPM air gap intake, 750 Vacuum holley and the above mentioned cam.
Its on a 107 LSA.
Being happy with it, doesn't mean it's close to optimum.

There are very few pump gas 355" SBC engines that will out-pull my boat engine
It's 10:1 with ported 492 heads, Performer RPM, and Holley 600.

RPM---TQ--BHP
3200--436--266
3400--443--287
3600--445--305
3800--444--321
4000--443--337
4200--440--352
4400--440--368
4600--441--386
4800--441--403
5000--432--411
5200--422--418
5400--412--423
5600--400--426

The cam is 216/220, on a 112 LSA, and 108 ICL
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Re: Small cams on 106-108 LSA’s

Post by Walter R. Malik »

Walter R. Malik wrote: Wed Nov 18, 2020 9:52 pm
Before he died and the assets of his company got sold, Bill Metzger at LAZER CAMS offered new catalogue cams like this.
He called them "Street Rod" cams; mainly because they would idle rough but, smooth out above 1,200 RPM on a cruise.
Power was not the "main" objective.

Years ago I bought and used many 302 Ford "Street Rod" cams from LAZER.
His cams were all ground in house because he was really a smaller, single person, business.
"Chief Cook and Bottle Washer" was the heading on Bill Metzger's business card. (He hosted many PRI conferences).
Looking into my past records ...that Small Block Ford 302 Cam was 205/210 @.050" ; .291"/.297" lobe lift, on 104 degree separation.
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Re: Small cams on 106-108 LSA’s

Post by piston guy »

In the '70s it was Racer Brown that "woke me up" regarding "cubic inches , air flow , and RPM" when looking for a camshaft. I had a Boss 302 and fell into "too little , too much and too broad" . It took three tries but we ended up with a "tight", moderate duration , very high lift ( for the day) to get torque at 3,000 and ability to still make power over 8,500. He warned this was application specific and it would be a stupid choice in a SBC because the heads were smaller( better suited) and didn't need the overlap. He taught me allot , much of which I still use toady.
Mike's "boat cam" on a 106*lsa +4 would be a stout cam in a street driven 351C but a dog on 112 even +6.
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Re: Small cams on 106-108 LSA’s

Post by frnkeore »

I don't know about CC but, Howards doesn't charge extra. As I remember, $138 was what it cost for the last SFT, SBF, I had done, about a year ago.
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Re: Small cams on 106-108 LSA’s

Post by digger »

it all depends on your goal for power band. when the duration is fairly mild the tighter LSA will make more at the bottom and middle but can lose a fair bit up top as the events are skewed that way. When the duration is higher the tradeoff is much smaller because of where the resultant events end up

e.g. small duration means earlier IVC all else equal as does tighter LSA so you get further and further from optimum IVC required to rpm the engine a bit
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Re: Small cams on 106-108 LSA’s

Post by skinny z »

Maybe drifting a little off topic but what if the goal is the most lbs-ft per CID? Not the broadest or "area under the curve" but the greatest peak? (All else being equal)
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Re: Small cams on 106-108 LSA’s

Post by skinny z »

skinny z wrote: Thu Nov 19, 2020 11:25 am LSA notwithstanding but isn't it the overlap that is a defining characteristic? Obviously intrinsically tied into the LSA along with duration but the separation angle in and of itself isn't the whole picture.
That said, it's been put forward here, with great debate, that certain engine profiles (and maybe I'm talking about a 10.5:1 355 SBC here) have a specific LSA that will reliably produce the best lbs-ft per HP.
EDIT: That should read lbs-ft per CID (Not HP). #-o
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Re: Small cams on 106-108 LSA’s

Post by travis »

Walter R. Malik wrote: Thu Nov 19, 2020 12:52 pm
Walter R. Malik wrote: Wed Nov 18, 2020 9:52 pm
Before he died and the assets of his company got sold, Bill Metzger at LAZER CAMS offered new catalogue cams like this.
He called them "Street Rod" cams; mainly because they would idle rough but, smooth out above 1,200 RPM on a cruise.
Power was not the "main" objective.

Years ago I bought and used many 302 Ford "Street Rod" cams from LAZER.
His cams were all ground in house because he was really a smaller, single person, business.
"Chief Cook and Bottle Washer" was the heading on Bill Metzger's business card. (He hosted many PRI conferences).
Looking into my past records ...that Small Block Ford 302 Cam was 205/210 @.050" ; .291"/.297" lobe lift, on 104 degree separation.
Did you ever have detonation issues with a cam like this on pump gas? And did they fall on their face around 4000-4500?

Many years ago, a friend had a mid 80’s Chevy short bed pickup...TH350C trans and 2.73 gears. It had a rebuilt but completely stock 8.0-1 compression 355 out of a mid 70’s something or other replacing the stock 305. When he rebuilt it he added a crane 272 cam cam that was 216/228@.050, on a 112 lsa. It was a turd. When the cam went flat he replaced it with a crane 194/204@.050 cam on a 104 lsa. It completely changed the truck...it would actually move pretty good for what it was. But even with no compression he had to run premium fuel, and it was completely done by 4000.
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Re: Small cams on 106-108 LSA’s

Post by travis »

CamKing wrote: Thu Nov 19, 2020 12:44 pm
prairiehotrodder wrote: Thu Nov 19, 2020 12:32 pm I've built 3 or 4 chevy small blocks with the smallest comp thumper cam. I am very happy with it.

For a fun, reliable 350 i use the Edelbrock E-street heads, flat top pistons, RPM air gap intake, 750 Vacuum holley and the above mentioned cam.
Its on a 107 LSA.
Being happy with it, doesn't mean it's close to optimum.

There are very few pump gas 355" SBC engines that will out-pull my boat engine
It's 10:1 with ported 492 heads, Performer RPM, and Holley 600.

RPM---TQ--BHP
3200--436--266
3400--443--287
3600--445--305
3800--444--321
4000--443--337
4200--440--352
4400--440--368
4600--441--386
4800--441--403
5000--432--411
5200--422--418
5400--412--423
5600--400--426

The cam is 216/220, on a 112 LSA, and 108 ICL
I can confirm this. My ford version of this build is the most responsive 351w I’ve ever built. It also has enough beans to completely wreck a 2500 stall street torque converter in a 4900 pound truck :( And it wasn’t a cheap converter either
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Re: Small cams on 106-108 LSA’s

Post by ProPower engines »

F-BIRD'88 wrote: Thu Nov 19, 2020 11:43 am What does comp charge to custom grind a sbc hyd or solid flat tappet cam these days?
I know if your a dealer Isky does not charge extra for any common FT Hyd. or Solid profile to move the lobe center or for that matter do a dual pattern custom without the need for a special core over their reg. WD cost.
And that is for any SM blk or BB engine. =D>
Cam cores are hard to get these days for some applications but if they have a suitable core no problem.

Most custom's we get done are under a week before they ship. Steel cams take about 7-10 days depending on the profile.
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Re: Small cams on 106-108 LSA’s

Post by n2omike »

I believe the rest of the combo needs to be taken into account when discussing LSA.
Tight LSA cams generally work with FREELY flowing exhaust systems. A restrictive exhaust KILLS a cam with overlap. Small cams are often used with stock exhaust manifolds and small exhaust systems. Overlap is bad with these, as all it does is cause reversion back into the cylinder. I've literally seen engines with carb bodies that were BLACK with soot from using a tight LSA cam with a restrictive exhaust. Tight LSA's need to BREATHE FREELY in order to work their magic... else, they are a step in the wrong direction.
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Re: Small cams on 106-108 LSA’s

Post by skinny z »

So, to follow that thinking, IF I have a 10.5:1 355 SBC AND I've got a well spec'd header that's open at the collector with a PipeMax calculated secondary length, all of which is strapped onto my dyno, which will make the greatest peak lbs-ft output?
A 112 LSA or 108? All else is the same.
Let's say that the overlap is 70 degrees (@ .006") for both.
Yes, very much the devil's advocate here but I'm interested in the view of all that contribute.
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Re: Small cams on 106-108 LSA’s

Post by ProPower engines »

n2omike wrote: Thu Nov 19, 2020 7:32 pm I believe the rest of the combo needs to be taken into account when discussing LSA.
Tight LSA cams generally work with FREELY flowing exhaust systems. A restrictive exhaust KILLS a cam with overlap. Small cams are often used with stock exhaust manifolds and small exhaust systems. Overlap is bad with these, as all it does is cause reversion back into the cylinder. I've literally seen engines with carb bodies that were BLACK with soot from using a tight LSA cam with a restrictive exhaust. Tight LSA's need to BREATHE FREELY in order to work their magic... else, they are a step in the wrong direction.
Dual pattern cams work much better with stock systems like intake and manifolds.
Most times I see carbon up the intake track as you mention is caused by a shit valve job and lack of valve to seat sealing.
Or older factory engines that have had abuse and the valves don't seal well enough to keep the burn in the bore that guys just stuff a stick in figuring it will be the best you get. I would have to believe the exhaust would need to be completely plugged up to get the intake track as bad as you say unless it's a POS to start with the only way you burn in the intake system is from a leaky valve
Thus it just burns back up to the carb base
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Re: Small cams on 106-108 LSA’s

Post by rfoll »

Crane has a cam for sbc, 218/218/106. I always thought it would be a killer setup for someone wanting the sound without using a monster cam and killing drive-ability. My question about this kind of thing is, what will it do to fuel economy?
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