Don Terrill’s Speed-Talk

Hi,with a 9:1 chevy 350 crate engine short block and afr 195 heads, whats the biggest cam I can run? I have some in the mid 240 @ .050 range one on a 110 and the other on a 105 or 106 I believe. This a street/strip car, 4.56 gear, 4k converter, vic jr intake etc etc. I can swap out to a flat top piston or small dome as long as I can keep piston weight the same so i dont have to rebalance. Is there going to be that big of a difference horsepower wise with more compression if I do? Thanks!!

IMO 10.5-11 is good for pump gas but to make gains in power with compression you need more than just one piont of compression to see a big difference.
240-250 on a 110-112 with good lift could get you where you want to go. They are doing alot with pump gas these day's. Get one of these guy's on here to get you a custom grind that will get you the power you want Good luck, hope fully Cam King will chime in.

T-flow

Large lift cams need more compression to run strong. Remember bigger isnt always better. A hyd roller cam would make a nice combination for your setup.

Real men DO NOT RUN hyd roller cams, especially if they want to drag race= Compreession is very important, even more so when you dont have any to begin with.


JOE SHERMAN RACING ENGINES

Your are effectively running 8.5:1 at best. Short of a torque building cam, there is little you can do with your set-up to get anywhere near the performance you will want. I'd swap in some pistons to get at least a mechanical 11:1 compression ratio, probably more because your set-up will never see a lugging situation.

tom

With all due respect, why do you want to know what the biggest cam you can run is?
Wouldn't you rather know what the correct cam to run is?
I know a lot of 358ci race classes that are limited to 9:1(9.5:1), and they run cams in the 260's, and over .700" lift.
I don't think that would be a good street/strip cam.
How many RPM do you want to turn the engine?
If that crate bottom end won't last beyond 6,000rpm, you don't want to go over a 230@.050"

Yes I possibly worded it wrong. Rpm is unsure but with the gear I have it wont be low. this engine is just to get me by for a little while until I build another. Ok,so kinda what I figured compression wise, I need to get more compression to run any decent cam to make power. Considering what I have at the moment , what size cam will work for me while I build another shortblock? Can I at least get 400+ hp with my low compression and a hydraulic cam?

mikes wrote:Yes I possibly worded it wrong. Rpm is unsure but with the gear I have it wont be low. this engine is just to get me by for a little while until I build another. Ok,so kinda what I figured compression wise, I need to get more compression to run any decent cam to make power. Considering what I have at the moment , what size cam will work for me while I build another shortblock? Can I at least get 400+ hp with my low compression and a hydraulic cam?

With 9:1, you can get 400+.
Since you need to turn it, I'd go a little big on the cam, and tighten the LSA, and advance the cam.
To get by for a while, I'd go with that 240 cam on the 105or106 you said you had, and put the intake in on 100.

Maybe the correct way to phrase the question would be: What is the CORRECT camshaft for MY APPLICATION?

I hate to nit pik, but there is a "correct" cam for the application, and most likely, it won't be on the shelf.


EDIT>> sorry Cam King...I should have read ALL the posts

240 ish ,106 lca at 100 icl, would be good to max hp at 6-6200...

1.6 rockers on intake side would be good also.

the one cam I have is the lunati voodoo 60105,
Advertised Duration : 284° /292°
Duration @ .050 IN/EX : 241° /249°
Gross Valve lift IN/EX .525''/.546''
LSA and ICL 110

My other cam is an old ultadyne 246-252ish that might be too big ? I dont remember the specs exactly but I know its on the upper side of 240's

Throw both cams in the air and install which ever one hits the ground first, (and doesn't snap in half)

Install the lunati cam on a 103 in c/L,, the other one on a 100 c/L

Install the heads with a shim gasket to max the cr on the stock motor.

Hi guys and thanks for the replies thus far. Well I found a couple more cams on the shelf that I had and was wondering if these might be better suited to my low compression . Out of these whats the best one to run? If I could swap out to a flat top piston, would I have to rebalance the rotating? Thanks again for the help .

First one is an old torker plus from edelbrock, here are the specs:

Duration at 0.006" Lift: Intake: 292° Exhaust: 300°
Duration at 0.050" Lift: Intake: 232° Exhaust: 234°
Lift at Cam: Intake: 0.325" Exhaust: 0.325"
Lift at Valve: Intake: 0.488" Exhaust: 0.488"
Timing at 0.050" lift: Open Close
Intake: 10° BTDC 42° ABDC
Exhaust: 47° BBDC 7° ATDC
Centerlines: Lobe Separation - 108° Intake Centerline - 106°

The second one is and old crane and the specs to this one are:


Lift: Intake @Cam 3347 @Valve 502 All Lifts are based
on zero lash and theoretical rocker arm ratios.
Exhaust @ Cam 3347 @Valve 502
Rocker Arm Ratio 1.5

Cam Timing: TAPPET @.004
Lift: Opens Closes ADV Duration
Intake 41 BTDC 73 ABDC 294 °
Exhaust 73 BBDC 41 ATDC 294 °

Spring Requirements: Triple Dual Outer Inner
Part Number 99848
Loads Closed 114 LBS @ 1.700 or 1 45/64
Open 329 LBS @ 1.220
Recommended RPM range with matching components
Minimum RPM 3200
Maximum RPM 6400
Valve Float 7200

Cam Timing: TAPPET @.050
Lift: Opens Closes Max Lift Duration
Intake 17 BTDC 41 ABDC 102 238 °
Exhaust 49 BBDC 9 ATDC 110 238 °