glamaina

Yes yet another Cam thread by someone sorry but after 2 years with my 350 in pieces I finally brought it to a machine shop to start the work so getting excitied.

Mahle Pistons
Bore 4.067(may be larger if it needs to be bored)
Cometic head gaskets
Performer RPM intake
Larger 455 valves
No other head work yet (porting polishing)
Headers
2500 RPM stall converter
3.23 Gears

calculates to about 9.4:1

I wont be racing this thing on track. I want a noticeable Idle, not stock idle but need vacuum for the brakes.

Howards recommended a Street Force 3 Summit Racing Part Number:HRS-512121-12


UPC:840793134564

Cam Style:Hydraulic flat tappet

Basic Operating RPM Range:1,800-6,000

Intake Duration at 050 inch Lift:225

Exhaust Duration at 050 inch Lift:235

Duration at 050 inch Lift:225 int./235 exh.

Advertised Intake Duration:279

Advertised Exhaust Duration:289

Advertised Duration:279 int./289 exh.

Intake Valve Lift with Factory Rocker Arm Ratio:0.496 in.

Exhaust Valve Lift with Factory Rocker Arm Ratio:0.501 in.

Valve Lift with Factory Rocker Arm Ratio:0.496 int./0.501 exh.

Lobe Separation (degrees):112

Computer-Controlled Compatible:No

Valve Springs Required:Yes

Camshaft Manufacturers Description:This camshaft has a noticeable idle. Street Force 3 needs a street 2,200-2,500 stall converter and 3.20 to 3.90 gear ratio. Good ignition system will give you additional performance.

Thoughts?

69HO43

I'm not a cam expert. Let's get that out of the way right now. The following is simply opinion. Grain of salt type of thing.

Sounds to me like it will do just nicely for what I presume you're looking for, but with a noticeable, but not an unreasonable cam lope at idle. While I did look at this grind for my stock 69 H/O, as I'm looking for a little more higher rpm pull, I got a better recommendation for my own application from eficutlass. I worry about the power brake aspect as well. But in a 350, this will act like a bigger cam than in a 455 obviously. The benefit is that you have a 112 LSA, so this is good for a street engine, albeit at the lower end of the "good vacuum signal" scale, IMO. You can always put in a vacuum reservoir tank to add to the PB system if looking stock isn't important and you'd maybe be on the edge of the power brake vacuum.

I'm not the end-all be-all of cam suggestions, by a long shot. I do know whatever cam you would use in a 455 is amplified to act like a larger cam in a 350. But I've always worried more about what the goal was for matching up the engine/gearing when installing performance parts. Allowing the parts to compliment each other to help reach the end goal. If you want just a lumpy cam sound to drive through a car show parking area, that's one thing, then put in a big lift cam and call it a day. But if you want it to truly perform, the cam lope at idle should simply be a by-product of the performance aspect of the cam. If you want it to pull more on the low rpm side as your gears suggest, that 2500 TC should do you very well. If you had a choice, I'd probably poke some 3.42 gears in there, but that's just me.

Fonz

I just installed a 204/214 .470 lift cam. PROBLEM being : some of these "aftermarket Cams" have a "SMALLER BASE CIRCLE" ! ( .100-.150" Smaller Than Stock), requiring LONGER PUSH RODS !!! my take is: if the base circle is .140 " Smaller than stock, you would need a PushRod that is .070" LONGER. are there any CAM Guru's out there to clear this up ??? Thanks

cutlassefi

ALL Aftermarket cams will have a smaller base circle. The stock camshaft usually only has about .030-.040 clearance between the nose of the lobes and number four journal. That’s the way they’re designed. Any increase in lift and duration is taken off the base circle, the nose stays just about the same distance smaller than the journal.
Op that cam has too much split and overall duration for your build. An Erson TQ40 is a proven grind in similar combinations. I would recommend that instead.

Fonz

but because of the lifter now being .075" lower in the lifter bore, isn't a longer push rod needed to make up the "difference" ?? Cam is already in the engine, so cam "choice" was already made. thanks

Qwik71442

Save yourself the headaches put adjustable rockers on it and be done...

Fonz

just throwing on adjustable rockers will take up the slack, but will not coorect the geometry of the rockers

Oldcoyote

Does the car have a 3 speed transmission?

glamaina

Asking me or the guy who hijacked my thread? I have a 3 speed th350

glamaina

Thanks mark, I'll look into that cam. I saw on another thread you used that in a similar set up and dynoed over 400hp? Did it have a noticeable idle?

Also, my engine builder is comp cam distributor. I haven't gotten to the point of discussions on cam yet with him but curious what the your thoughts are on comp. Any comparible to Erson? Or stay away. Thanks

cutlassefi

A lot of engine builders are “Comp” guys, I am too.
But I’ve had a bunch on the dyno so I know what works and what doesn’t, most others haven’t. I’d be interested to hear his choice, but more importantly “why”. Most look in their catalog not really knowing what to pick and why.
Yes it made over 400 and had a nice noticeable idle. It turned out to be a nice little build.

Hope this helps.

glamaina

I'll be sure to let you know what he recommends when I get to that point. Thanks again.

Oldcoyote

Yes, you thanks. That explains the 3.23 which is what I used on a Turbo 400.

glamaina

Hi Mark, you said you were curious what he recommends melling. Here it is. He just sent me this pic. Def milder than the erson. Thoughts?

dragline

Mike Jones in Denver, NC is the best cam designer in the country. I won't buy from anyone else. More power and easier on the valve train.

http://jonescams.com/street-performance/

cutlassefi

This just proves what I’ve said over and over, most “engine builders” don't have a clue when it comes to picking the right cam.
It’ll be a stock or nearly stock idle, not make a lot of power and be something you’re not happy with based on your original post.
I stand by my original suggestion.

glamaina

So just for my own edification (trying to learn) if you could elaborate on your comments on the specs of that Howards Cam that would be great. You say too much split and duration but the durations are closer together than the TQ40. Im sure im just not understanding the terminology. Overall duration is less on the Howards as well yet your saying too much duration on the Howards. What am I missing? I am also curious as to the high exhaust duration on the Erson I havent seen too many with such a difference between the intake and exaust durations. Most seem to be about 10-15 degrees apart. Whats the significance of that?

Howards Cam Duration at 050 inch Lift:225 int./235 exh
TQ40 Duration @ .050: 220/280

Also, that was me who emailed you about the TQ40 the other day, thanks for the reply.

thanks!

Bubba68CS

Your instinct that something isn’t correct with the exhaust duration is sound. 280 is a typo on their site. Cam card shows 228 on the exhaust at .050.

glamaina

Well that makes more sense. Also answers my other questions then I believe.

The erson seems very close to the comp cam 42-223-4