[rustycarr]

Ok ive got a 1971 455,3.55 gears,4 speed/4bbl/ getting ready for a rebuild and my machine shop recommended a Ram Air III cam. Ive heard alot on this board about Crower 60243.

here are specs ive found:


Int / exh / int@50 / exh@50 / lobe

284 / 290 / 228 / 235 / 112 crower
301 / 313 / 220 / 228 / 110 ram air III



any comments on this? The ram air looks like a bigger cam to me but i dont know sap about cams. He said the Ram air 3 can retain stock rockers.

[Don 79 TA]

i myself am a fan of the RAIII cam, but thats personal preference
makes a nice sound, broad power range, however for making max power there are better ones out there

I have the lunatti version, which is choppy in the 400, not sure how it would be in a 455
the III cam is great for manual tranny's

just make sure to pick the cam that matches everything else that you have for optimum performance
also the III is very easy on the valvetrain too, even with 1.65 rockers

[Kenth]

Not sure wich cam you refer to as the RAIII cam?

Here is the original specs:

Pontiac 9785744, 301 313 advertized, 224 236 @ .050", .410 .410 lift, 119 LSA, 76 overlap.

I use it myself in my 455 with #96 heads RA exhaust TH400 and 3.55, runs 13.7 with tires spinning half the track (regular tires).
This cam MUST have valvesprings with approximately 125lb @ 1.586" installed height due to the shape of lobes.
Valve float WILL occur at lower rates.

[se428bandit]

Originally Posted by rustycarr

Ok ive got a 1971 455,3.55 gears,4 speed/4bbl/ getting ready for a rebuild and my machine shop recommended a Ram Air III cam. Ive heard alot on this board about Crower 60243.

here are specs ive found:


Int / exh / int@50 / exh@50 / lobe

284 / 290 / 228 / 235 / 112 crower
301 / 313 / 220 / 228 / 110 ram air III



any comments on this? The ram air looks like a bigger cam to me but i dont know sap about cams. He said the Ram air 3 can retain stock rockers.

There are 2 version of the RA III Cam [auto 068 and Manual 744] both have the same lift but the Manual has more duration [224/236]vs [068 212/225].I have used the 744 adv 4 degrees in a low comp 400 and had great results but also used an 2800 stall as it was a pig with the stock 1800 converter.

[Kenth]

Some gearing would help too, Pontiac used 4.33 in the 1967 GTO RamAir as standard gears with the #744 cam.

[David Jones]

Originally Posted by Kenth

Some gearing would help too, Pontiac used 4.33 in the 1967 GTO RamAir as standard gears with the #744 cam.

I don't see the need for the short gears with a Ram Air III style cam and a 455. 3.23/3.36 gears would be more than fine with the torque that engine would have.

It wouldn't need the 3.55's unless he just liked spinning the tires a lot...........

[Kenth]

Originally Posted by David Jones

I don't see the need for the short gears with a Ram Air III style cam and a 455. 3.23/3.36 gears would be more than fine with the torque that engine would have.

It wouldn't need the 3.55's unless he just liked spinning the tires a lot...........

Just a reply on the converter comment, Pontiac tended to use more gears with hotter camshafts instead of converters with higher stall speeds?
For a 455 3.55 is plenty, i´m leaning on a 3.07 for my Judge wich i think would be perfect for this combination?
Didn´t the 455SD T/A use 3.07 gears for A/T?

[David Jones]

Probably wouldn't need too much converter with that 4spd........

[Murf'sDad]

Originally Posted by Kenth

Some gearing would help too, Pontiac used 4.33 in the 1967 GTO RamAir as standard gears with the #744 cam.

As I remember if you got the 744 cam you had to order the 4.33's or the car was an absolute pig off the line. Story or legend has it that an exec took out a car (GTO?) with the 744 cam and stock 3.08 or 3.23 gears and thought it was almost undriveable. Came back and said the 068 was to be the RAIII cam. But who knows?

MTC, Stewart

[Kenth]

Originally Posted by David Jones

Probably wouldn't need too much converter with that 4spd........

1967 Firebird HO/RA TH400 code is PQ.

1967 GTO HO/RA TH400 code is PX.

[Kenth]

Originally Posted by Murf'sDad

As I remember if you got the 744 cam you had to order the 4.33's or the car was an absolute pig off the line. Story or legend has it that an exec took out a car (GTO?) with the 744 cam and stock 3.08 or 3.23 gears and thought it was almost undriveable. Came back and said the 068 was to be the RAIII cam. But who knows?

MTC, Stewart

That would be correct for 1969 RAIII, since the cam changover occured in halfway into production?

[se428bandit]

RustyCarr i think you are looking at the Lunati Ram Air III cam 424 lift/ 220 228 duration.You shouldn't have any problems with that cam.I have ran a Ram Air IV in a 455 with 96 heads with a 3.23 gear and it was my everyday ride.What heads are you running on your 455?

[rustycarr]

stock 1971 455 heads, i think they are #66

[PONTIAC LARRY]

Definitely use the 112 ls Crower on a 8:1 455 over a 115.5 ls #744 cam.

If you had 9:1 or more, then I would use the 744 ..

[tryconcom]

Hey gang; I have used the 744 with 3:55s and 3:90s. In both cases, it ran great, In one case I had it in a 66 tricarb 389 gto -the car was easy to drive. I was running a wide box, 3:55s, and 1.65 rockers and H.O. racing specialties ram air springs-it would routinely pull with power past 6 grand. I swaped it out for an nos 041 in the tube I found at Pomona in 91, car ran like gangbusters-unbeleveably strong to 6+. In the other car, my current ride, a 69 special order paint (code 72) GTO, I have the 744/413 cube combo driving a another wide box and 3:90s. Again, a strong streeable combo-you won't be top eliminator at a national meet, but you will be strong on the street. Another thought- the 068, 744 and 041- all designed for cars waranteed for the days of 5yrs/50,000miles-designed by pontiac engineers for pontiac engines-they worked well together-just my 02cents.

[se428bandit]

Originally Posted by rustycarr

stock 1971 455 heads, i think they are #66

Are the heads still press in studs or have they been changed to screw in studs.I used a Ram Air IV cam in a 73 [stock]4x headed 455 before and i ran 8.90's [1/8 mile] with a 3.23 gear.But with a press in studs i would go with the cam with the smaller lift.

[Cliff R]

The larger 744 Ram Air III camshaft has never been overly popular. It was the last effort by the engineers to continue to add duration without increasing valve lift. I think they may have started down the path of diminshing returns with it, not sure?

What I do know is that when they werer still readily available, I tried one in a well prepared 428 engine. It ran fine, tad "rough" idle and decent power, but I wasn't overly impressed with this cam anyplace. The engine lost a thrust bearing early in it's life, and was rebuilt with an HO Racing HC01-A camshaft. The higher lift cam just worked better everyplace. Improved idle, stronger mid-range and pulled equally as well at high rpms as the 744 camshaft.

At that time our car didn't hook well enough or run consistant enough for averaging track numbers. We also changed from #96 to 6X-4 heads during the overhaul/rebuild, so the numbers would be flawed anyhow. The new engine did propell the car considerably faster than the old one, and we liked it's street manners better at every level.

The Crower 60243 cam is an excellent camshaft in the 400 engine with at least 10 to 1 compression, 3.73 or higher gearing, and manual transmission or at least 3000rpm stall converters with the auto trans.

I haven't used or tested one in a 455, but have recieved excellent feedback from users of them in that application. Personally, if being used in a 455, I'd limit the SCR to about 9 to 1 or just a tad higher. Above that I'd move up to the 60919 grind......Cliff