I would stay under 230@.050, There are many other variables you need to tell us, what size BB, manuel or auto tranny, rear end gears...and so on

 

427 = 060 for 440
TH350
3.08 rearend

 

Your 308 gear is not helping matters but with only 9:0:1 comp i would not go over approx 220-225(MAX) deg dur @.05 on a 112 LSA,not 110 LSA.

Scott

 

My buddies old 67 camaro had a 9:1 454 with ported and polished 990 heads and a Chet Herbert solid 255/265@050 .600/.620 and it ran 11.20`s with a 10" converter,4.11 gears and 28x9 slicks.

 

I consider that VooDoo cam about perfect for a pleasant street BBC, particularly at 9:1 and a 3.08.
At UltraDyne, we ran as big as 231/239 in 8.8:1 454s at Mercury Marine. They didn't make as much power as they would have at 10.5:1, but they ran.....OK. But in a street car, they would need more rear gear, say 3.7:1. And a big 1/2" fuel line.....

UDHarold

 

Harold, just how much would one be giving up runinng say a 231/239 cam w/9.1-9.5 instead of 10.5?

Does the power loss justify running a smaller cam?

 

Voodoo 60203.......
Advertised Duration IN/EX: 268/276
Duration @ .050 IN/EX: 227/233
Gross Valve Lift IN/EX: .542"/.554"
LSA / ICL: 110/106

OR


Voodoo 60204 on a 112lsa.....

 

Aaron,

I reiterate what I had written, especially about using the Voodoo 60203, from seeing your last post.

 

Vince,

Same dyno, 2 different 355s, very conservative dyno.
355 Targetmaster, 600 Holley, Performer, 1 5/8 headers 231/239, about 8.8:1----365 BHP at 5700.....
355 10.25:1, 750 Holley, victor Jr. not sure on headers, same 231/239----415 BHP at 5800.....
It's worth it. However, increasing the CR is an ever-diminishing game. Going from 9 to 10 gives a bigger percentage gain than going from 14 to 15. However, in some racing, 2 BHP means winning vs losing.

UDHarold

 

Harold,how would a 238/248 @ .050 cam on a 114 LSA be in a 9 to 1 454?

 

Great info UD thanks!!!

 

A 255 int dur@.05 cam in a 454 with only 9:1 comp running low 11's,was there NOS hidden somewhere? Generally that cam would be too big on duration for a 9:0 comp 454 in reality. I am talking about the avg Joe here that would be caming up his 9:0 comp 454 street motor and accidentially overcam'd it with 255 int dur@.05 with only 9:0 comp. But i am sure a savy engine builder (which this guy could be)could have come up with just the right combo to get a big 255 deg dur @.05 cam to work in a 9:0 comp 454 motor like stated. But it's not the norm for sure & i would not rec anything close to that 255 cam for this guy,wrong thing to do in a 9:0 comp 454 street motor/car IMHO.

Does anyone else think in general that 255 deg dur@.05 in a 9:0 comp 454 is too large and not a good choice or am i missing something obvious here? Heck,i think in general a 255deg dur @ .05 cam is stout/big for a street 454with 10:0 comp. It would likely rock/shake the mirrors off the car at idle,thats plenty of cam for a hot 10:0 comp 496-502 motor with approx 50 more cubes to eat up a little more duration..

As already suggested the Voodoo 60203 gets my vote too as the largest i would install in a 9:0 comp 454,why push it. This cam is conderably hotter then what he is currently running so it should give a decent perf inc without possibly over caming the motor and sending some of his somewhat low( but not bad for street/should have no ping issues) 9:0 comp he has out the exhaust with too much cam.

But if he goes larger on cam then the Voodoo 60203 (227/233 deg dur @.05)whats he gong to gain if he truely has only 9:0 comp as he stated? Who knows he may have smidge less compression because as we all know the est of comp in motors if often in error on the high side and is a little lower in reality then expected so his comp could poss be lowere then 9:0,who knows.

Scott

 

A 255 int dur@.05 cam in a 454 with only 9:1 comp running low 11's,was there NOS hidden somewhere? Generally that cam would be too big on duration for a 9:0 comp 454 in reality. I am talking about the avg Joe here that would be caming up his 9:0 comp 454 street motor and accidentially overcam'd it with 255 int dur@.05 with only 9:0 comp. But i am sure a savy engine builder (which this guy could be)could have come up with just the right combo to get a big 255 deg dur @.05 cam to work in a 9:0 comp 454 motor like stated. But it's not the norm for sure & i would not rec anything close to that 255 cam for this guy,wrong thing to do in a 9:0 comp 454 street motor/car IMHO.

Does anyone else think in general that 255 deg dur@.05 in a 9:0 comp 454 is too large and not a good choice or am i missing something obvious here? Heck,i think in general a 255deg dur @ .05 cam is stout/big for a street 454with 10:0 comp. It would likely rock/shake the mirrors off the car at idle,thats plenty of cam for a hot 10:0 comp 496-502 motor with approx 50 more cubes to eat up a little more duration..

As already suggested the Voodoo 60203 gets my vote too as the largest i would install in a 9:0 comp 454,why push it. This cam is conderably hotter then what he is currently running so it should give a decent perf inc without possibly over caming the motor and sending some of his somewhat low( but not bad for street/should have no ping issues) 9:0 comp he has out the exhaust with too much cam.

But if he goes larger on cam then the Voodoo 60203 (227/233 deg dur @.05)whats he gong to gain if he truely has only 9:0 comp as he stated? Who knows he may have smidge less compression because as we all know the est of comp in motors if often in error on the high side and is a little lower in reality then expected so his comp could poss be lowere then 9:0,who knows.

Scott

That was all motor. The motor was a 1971 LS6 wich has 9:1 compression and open chamber heads which the 990`s are. The numbers on the tops of the pistons confirmed it. The heads were fulley ported and polished and were off of his low 10 sec. 427 after he sold the shortblock. The cam was actually recomended but the guy at Chet Herbert. I don`t know if it was chet himself or not. He did say to install it 4 degrees advanced. It ran great and pulled very hard up to 6500rpm`s. I know he did`nt expect the Et he ran. He was able to tune it to 11.50`s before with stock unported 990`s and a mild Crane Fireball solid. The car ran great and did`nt"rattle the fenders off" but it have a really nice ide to it, it was a 110LSA. Alot of people could`nt believe it was only 9:1 compresion but it was and ran 11.20`s at 122mph.

 

I have also seen some low compression 454's with large cams run well at the track,but they had 3.73-4.10 gear and 4000 flash stall convertor

 

YAh , all you really need is a transbrake with a 5000 converter.Bet you could run quick all day..
IN REALITY A 255 @.050 IS JUST WRONG ,FOR 9.1 COMPRESSION..

 

SSChevellefan,Wow,thats a nice have your cake & eat it too motor setup,i bet that never detonated or had hot start issues with all that cam in only 9:1 comp.

Thats a great motor setup i bet some T/CR's will copy to run on pump gas for sure.

But those heavily ported heads sure helped it dip into the 11's.

Do you happen remember what pistons(Stock dome height for 71 LS6?)carb,intake,rockers,& headers were used to complete the combo?

Thanks again for sharing the story with us on that motor setup. (BTW,i am over 50yrs old/been working on mild BBC/SBC street perf motors for 35yrs+ but can still learn from others,amazing, LOL!!!!!!)

Scott

 

SSChevellefan,Wow,thats a nice have your cake & eat it too motor setup,i bet that never detonated or had hot start issues with all that cam in only 9:1 comp.

Thats a great motor setup i bet some T/CR's will copy to run on pump gas for sure.

But those heavily ported heads sure helped it dip into the 11's.

Thanks for sharing the complete story with us on that motor setup.

Scott

well I can tell if your serious or being a smart ass but I can tell you that many people never believed that it was only 9:1 compression. The pistons came up as 1971 LS6 9:1 pistons in the GM performance book at the time. I don`t know what the flow numbers were to the heads or what valve size they were either but I know they were on his 12.5:1 427 that had a .650 Isky solid roller and ran low 10`s @133mph. He was running 11.50`s with unported 990`s and when he swapped on the ported one`s he did`nt gain anything untill he did the cam swap. I don`t remember it very having starting issues. He was very good at tuneing it as well. It was a great set up and was very streetable but he was greedy for power understandably. We have lost touch over the years but I hear he has a low 8 second camaro now.

 

Adding more fuel to the fire (More Fuel! More Fuel!!), How big a cam you can run in a 9:1 454?
It's not hydraulic, but solid, but we put the Lunati 402A7LUN in a lot of 9:1 or thereabouts 454s-468s for off-shore boats, and yes, they ran on 87-octane.
The specs are 288/296 at .020, 255/263 at .050, .612"/.630" gross valve lift, and 110 LSA. On ProMotor Engineering's dyno, a 468 pulled 561 BHP about 6400, and was decent at 3000. It also liked more compression, all the way up to 13:1.
A lot of TC members have this cam or the old UD 288/296F10. It works in street engines, but as always, the more compression, the better.

UDHarold

 

SSchevellefan,not trying to be a smart ass at all.

Its a great perf motor combo you told us about and i just wanted to get a little more info on it.

Scott

 

SSchevellefan,not trying to be a smart ass at all.

Its a great perf motor combo you told us about and i just wanted to get a little more info on it.

Scott

no problem, net is hard to tell if people are being a smart ass or not. I know I really liked the way the car ran and planned to copy the motor at some point and probably will someday but i think harlds 288/296 would be a better cam. i think the Chet Herbert was in the low 300`s advertized.

 

I've run more cam than what matched the CR. It tends to hurt bottom end but with a high stall and low gears, they will make power on the top end. It makes for easier traction control. With 3.08 gears and a tight stall, a too big cam will hurt power everywhere as it will never get into a good power band. For this combo/car I would err on the smaller side. You would want the bottom end with a heavy car, high gear, and tight stall.

 

Where do you want to make power? It is not a question of how much cam it will take but where you want you powerband to be. I've cammed 9 to 1 18 degree headed asphalt stuff that ran 250ish and 260ish duration @ .050" that ran like raped apes but the power band was from 5800 to 8200 rpm. Now put that same came in the same engine and gear it to run a max of 6000 rpm with needed power from 3800 to 6000 it would be a "pig".

Lift is the ability to make power, Duration is the ability to sustain that power in a given rpm range. So the question is, Where do you want this BBC to make power?

 

Something not mentioned in this post, unless I missed it, is intake port velocity and 9:1. With a good flowing, high velocity head, you are going to get in a lot of air, and 9:1 with a full cylinder of mix will run well. If the engine in question was running over 100%VE, then the effective CR would be over 9:1. Of course, DCR also increases with an increase in VE. Plus, a good midrange SR did not hurt this combo.

Horsepower comes from above the head gasket. The 454 must have hit the sweet spot of the heads, manifold, and cam timing involved.

255* in a fuel injected, 9:1 engine would run much smoother and have a broader torque range than carburated.

Getting back to the original post, 3.08 will not be the hot setup unless you go to a lot of stall speed. This is one more instance where you need to follow Harold's advice. As someone else said, pick the RPM range you want, then get the cam that fits that range. All cams are a compromise. That's why I always say the first thing you should do is select the cam, then build a car to fit it.

 

1971 LS6 motor will have a .095 tall dome (LF2399)

 

Well, this motor will be going into a truck. This truck will be used for working and having fun as a daily driver type of deal. Commuting for about 10 miles one way, hauling farm stuff off and etc. Something I can burn 87 octane in. I started off not trying to dump to much into the truck. Just something to have fun with.

This is what I have. 427 tall deck bored .060 over. Steel crank, Eagle rods (6.535) KB hypers (Part # 167, I believe, -17 dome). Heads are stock 781's. Cam is the Voodoo 60201. Summit headers, Team G intake with a 750 Holley. HEI of course.

Tranny is a TH 350 with stock converter with Transgo shift kit. The rearend is a 8.5 10 bolt with a 3.08 posi.

Thanks

 

I've ran low compression (9.0 & less) with larger cams before also. Sure they run decent, until you get behind a motor with the right compression and realize the throttle response you leave behind.