Hey guys, I'm getting close to finishing the rebuild of the 347 to put in my ranchero. I was trying to decide between intakes today, if I wanted to install a Stealth or an Air-gap. I have both and decided to go with the air-gap mainly because it looks cooler. Do you think I made the right choice? Heads are old style twisted wedgies, cam is comp 282S with 236/236 duration and .528 lift.
Weiand Stealth vs. Air-gap on a 347?
- Thread starter Fast63
- Start date
dennis112
15 Year Member
Hope you are running a hood scoop (or plan too.) The air gap is taller than the Stealth and can lead to installed height issues.
ratio411
Founding Member
CarFreakGT
20+ Year Stangneter 
I was trying to decide b/w the same two intakes, and I went w/ the Stealth due to its lower profile and (advertised) broader power band. Ultimately, my hope is to build out a 347 stroker. I just have a ton of other 'projects' to tend to first on the car.
Decurion
Member
Ill say go with the air gap. Also, if youre just looking for a strong street engine, the cam you picked is kinda big, especially depending on stall speed and rear gears. My 302 has 185cc heads, .500 lift, 222* @ .050, 3.55 gear, 2500 stall, and its a turd under about 3000. So you have more cubes, but more cam as well. Doesnt help me any that the old governor in the trans shifts it at 4700. 
Ya, I have a little work to do.
Ill say go with the air gap. Also, if youre just looking for a strong street engine, the cam you picked is kinda big, especially depending on stall speed and rear gears. My 302 has 185cc heads, .500 lift, 222* @ .050, 3.55 gear, 2500 stall, and its a turd under about 3000. So you have more cubes, but more cam as well. Doesnt help me any that the old governor in the trans shifts it at 4700.
What intake and carb are you running? With the cam you have, it ought to turn on at 1000-1500 with a dual plane and the right carb.
Ill say go with the air gap. Also, if youre just looking for a strong street engine, the cam you picked is kinda big, especially depending on stall speed and rear gears. My 302 has 185cc heads, .500 lift, 222* @ .050, 3.55 gear, 2500 stall, and its a turd under about 3000. So you have more cubes, but more cam as well. Doesnt help me any that the old governor in the trans shifts it at 4700.
The cam is what came with the engine when I bought it. A little big for what I am planning, but I have read some posts on other sites where people say it is fine on the street. I'll be running 3.55 gears and a 2400 stall. The description of the cam says its range is 2000-6000 and I installed it 2 degrees advanced for a little more low end. 63 rancheros are really light, they are lighter than 64-66 mustangs, so I am not too worried about it.
ratio411
Founding Member
If it was a hydraulic cam, I would agree, however it is solid.
Combine that with the extra cubes and dual plane intake, and you got a good street combo there.
A 236* solid will act like a 221-226* hydraulic cam.
Add to that the extra cubes taming the duration, and that cam is effectively smaller than your 222* hydraulic in a 302 cube engine.
Solids have much better low end and throttle response... very good combo IMO.
Decurion
Member
After rethinking my previous statement, I think the heads are a little on the big side causing a little sluggish low end, not so much the cam. Carb was 600 vac sec holley, RPM (non air gap) intake, long tube headers, 2 1/2" pipes. I did some more looking, and my cam is essentially a flat tappet version of the FRPP "E" cam. I think a set of 165cc heads would really wake up the low end without sacrificing any top end since its only a 302 and not a bigger 347. :OT:
In any case, I still vote for the RPM air gap.
In any case, I still vote for the RPM air gap.
Decurion
Member
Im not sure I understand your logic. Wouldnt a hydraulic cam bleed off a little bit before the valve actually started opening, giving a smaller effective duration?
EDIT:
And TIGHT! I have a 65 Falcon and Comet, both wagons.
Are you familiar with tffn?And TIGHT! I have a 65 Falcon and Comet, both wagons.
Yes, you PM'd me about it! I haven't signed up yet though, but have cruised there a little. Been spending too much time on my ranchero
i had a stealth on my 347(afr165's e303 cam 700dp holley 2500rpm stall). very strong midrange, adequate low end torque and became wheezy around 5200 rpm but would still make touque to 6000 rpm. later i did a megasquirt setup with a ported truck lower intake and home made upper. low end torque got a nice bump mid range suffered a little and pulled hard as hell to 5800rpm. hopefully this will give you a reference on torque curve.
ratio411
Founding Member
A solid cam compared to a hydraulic will act like it has 10-15 fewer degrees of duration. Don't know why off the top of my head... Just something I learned years ago.
Then, on top of that, you can run a tighter or looser lash and fine tune duration...
Solid cams make more throttle response, rpm, vacuum, and noise.
Less lope.
SoCalCruising
Founding Member
Those intakes are a toss-up, unless you want to port one. The RPM has several runners with equal cross sectional area, and are not amenable to porting. They can be Extrude Hone ported, since that will open up the entire runner. The Stealth has good taper on all runners, allowing you to open up the ports to match your heads, while still maintaining some taper from the plenum to the port. I have opened up a Stealth to match my 185s and the match was fairly easy to do.
that's good infro blkfrd. I set my lash at .022 so that it will be a little tamer for break-in and initial driving. If I want it bigger, I'll tighten that sucker up, haha.
I wasn't planning on porting the intake. I am not looking for all out power anyway. Thanks for the input everyone.
I wasn't planning on porting the intake. I am not looking for all out power anyway. Thanks for the input everyone.
It's due to the lash, the lifter doesn't move the valve till the lash (slack) is taken up first.
ratio411
Founding Member
I didn't think I needed a disclaimer for that.
Ramps are proprietory and a 270H from one company won't be equal to the 270H from another maker, much less comparing apples to oranges with hydraulic vs solid.
I figured that was elementary.
The whole point of my post was that hydraulics cannot be compared to solids using duration.
I should have left it at that.
Edit:
Btw, no part of this post should be construed as smarta$$!
Just clarifying my comments as you just might have a point!
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