[Ben M.]

Originally Posted by 77 TRASHCAN

I don't have a clue what size the chambers are on your 4X heads, But the 068 would be a minimalist cam choice to me for a 455.

Advertised as 114cc for an 8.2:1 compression ratio! Not called "soup bowls" for nothing ;-) I've done the 6X-8 + 455 build before and it was impressive. The 068 does seem like a good choice, I just hear so much flak from people on how it's "old technology." I've got a clone of it in an 8.5:1 400 with 3.55 gears and it's plenty fun to drive.

[68azbird]

Originally Posted by 72LuxuryLeMansLa.

You want to define "big turd" for us? According to SD Performance "In a recent dyno test this cam installed in a 464ci engine with 9.5 to 1 compression, a set of our 250-260cfm CNC ported #11 cast iron heads, CNC ported cast iron Q-jet intake and a prepped Q-jet carb made 503hp and 575+ lb/ft of torque on 91 octane."

In my world 575lb/ft and 503HP does not equate to a "big turd" but is a respectable car. WE ARE in the street section after all.

Lol
Engine had 4x cnc SD heads and same compression and was done by 4500 rpm
3900lb car ran 13.25 - 13.40's
Didn't run much faster when he changed to edelbrocks and 2 camshafts later.

[ponyakr]

I see guys always jumping from an 068 to an 041. What about the 744 RA3 stick cam. I've heard at least one guy really badmouth this cam. But, on paper, it looks like it would be just a bit better than the 068 in a 455--somewhere between the 068 & the 041. Just lookin at the specs on the Summit cams, it appears that the 2801 is just a higher lift version of the 068, and the 2802 is a high lift version of the 744.

So, how bout it ? Anybody use the 744 in a 455 ? How bout the 2802 ? I realize we are talkin low rpm grunt here, below 5000rpm.

http://www.ebay.com/itm/Engine-Camsh...4bee4b&vxp=mtr

Then I suppose the next step up, but just below the 041 is the Crower 60243. So who has some results to report on this cam. I think I've seen Cliff mention this one.

http://www.crower.com/camshafts/pont...m-284-hdp.html

[android 211]

Pontiac released it as over the counter first then in Ram Air cars with no ac and 4.33 or 3.90 axle only. Four speed only. Same for '67, '68 and '69. No low end. The story goes some Pontiac exec was driving one in the winter and dissatisfied with the cold weather driveability. It was dropped as even the RA cam and substituted with the 068. The lobe profile is a bullnose and hard on valvesprings; high pressure springs are required to get the most out of it. Under a different part number however because of the different distributor drive gear it reappeared as the 455 SD cam.

[ponyakr]

"...Under a different part number however because of the different distributor drive gear it reappeared as the 455 SD cam."


So then, I suppose you could say the 744 grind ran OK in a fairly low comp 455 ? They had originally planned to used the 041 grind cam in the SD455. I've read that it should not be used below about 9:1 CR. So, how would that have turned out ? That brings up the question, what is the minimum CR for an 041 cam in a 455 ?

Just can't help it. I love to read this Jim Hand stuff.

http://www.dapa.org/building-a-stron...iac-camshafts/

[steverino]

Funny, when calling the "tech line" at comp for cam selection advice, I had that "cubicle" feeling after hanging up

Obviously a popular topic here, lots of good info and shared experience , including that last link to more great experience shared by Jim Hand

I also feel that it's two different worlds between HR and HFT cams, and don't see myself considering the HR route anytime soon , so am focusing on the HFT info

I am also uncertain if I'd like the Rhoades lifters (restored stock looking gto convert), but I'd really like to hear them in person if there's anyone in central/eastern MA , southern NH that is running them ? Maybe I could catch up with them at an event somewhere over the summer

On the other hand, (and seemingly supported by that last Jim Hand article linked), I may not absolutely need the variable lifters if I were to switch to an 041 style cam, since I have a manual trans and manual brakes ? (currently I have 14" vac @ idle)

So I'm also wondering if anyone uses an 041 in a 455 with standard lifters , and with 1.65 or 1.5 rockers ?

I guess at 9.4 I could use an 041 cam, but if I wasn't planning to try the Rhoades lifters, what option might I have ?

It's obvious that the Rhoades with certain cams (041 etc) are a proven performer, but what about HFT options with standard lifters ?

My current "plan B" (if dissatisfied with the xe274), was/is the crower 60243 , but I'm not sure how much of a difference I would experience or if it would be worth it

[Cliff R]

I would avoid the real 744 cam as it was just too much duration for the low .406" lift. That cam is pretty much obsolete by modern standards. They can be made to work, but it becomes difficult to keep the lifters on the lobes without a lot of spring pressure, and probably why Pontiac limited it's use and developed the RAIV grind instead. The 2802 is a much better choice if you are looking at a cam in that range.....IMHO.....Cliff

[Cliff R]

I really don't think there is that much difference between hydraulic flat tappet and HR grinds, or not as much as folks think.

We can easily mimic the power of a HR grind with a very well chosen hydraulic flat tappet cam topped with Rhoad's lifters and high ratio rocker arms. We did that test a few years back right on the dyno between the Crower 60919 cam and a custom ground Comp HR cam with 230/242/112 specs. It had .361" lobes and quite a bit more lift than the 60919 cam, but only made 3hp/4ft lbs more torque on the dyno in back to back pulls.

The Crower cam had 1.73 rockers on it, and Rhoads lifters, and actually made peak power 200 rpm higher in the rpms range than the custom HR cam.

On back to back pulls we saw 494hp/540tq from the 60919 cam, and 497hp/544tq from the HR. Then we put the high ratio rockers on the roller cam and started swapping intakes/carbs/spacers, and ended up making 514hp/567tq by the time we were done, so it did open things up for more power with some additional work

The test still shows how well a flat tappet cam works in these engines, and we can "tame" it some with Rhoads lifters and bring on big power with high ratio rockers.

We recorded 12" vacuum at 750rpms with the 60919 cam, and 13.5" with the custom HR, so you really can get it done with a roller cam with less seat timing. The Crower cam had 304/314/113 specs, and 231/240 @ .050". The HR was 284/296 seat to seat, 230/242 @ .050".

The test engine was my old 455 with unported KRE "D" port heads with 85cc chambers, so about 10.5 to 1 compression........Cliff

[scooter1966]

Originally Posted by steverino

Funny, when calling the "tech line" at comp for cam selection advice, I had that "cubicle" feeling after hanging up

Obviously a popular topic here, lots of good info and shared experience , including that last link to more great experience shared by Jim Hand

I also feel that it's two different worlds between HR and HFT cams, and don't see myself considering the HR route anytime soon , so am focusing on the HFT info

I am also uncertain if I'd like the Rhoades lifters (restored stock looking gto convert), but I'd really like to hear them in person if there's anyone in central/eastern MA , southern NH that is running them ? Maybe I could catch up with them at an event somewhere over the summer

On the other hand, (and seemingly supported by that last Jim Hand article linked), I may not absolutely need the variable lifters if I were to switch to an 041 style cam, since I have a manual trans and manual brakes ? (currently I have 14" vac @ idle)

So I'm also wondering if anyone uses an 041 in a 455 with standard lifters , and with 1.65 or 1.5 rockers ?

I guess at 9.4 I could use an 041 cam, but if I wasn't planning to try the Rhoades lifters, what option might I have ?

It's obvious that the Rhoades with certain cams (041 etc) are a proven performer, but what about HFT options with standard lifters ?

My current "plan B" (if dissatisfied with the xe274), was/is the crower 60243 , but I'm not sure how much of a difference I would experience or if it would be worth it

Here is my experience with the XE274 cam. Engine is a 455 40 over, 1.65 rockers, 6X heads that have been milled 20. Compression is at 9.2.The heads got the Jim Hand porting at home, but I only did the bowl work and did not touch the ports. 32 deg total timing all in at 3k. Th350, Continental "J.Hand" converter with 3.89 rear. 750 Holley on a Torker 2. 275/50/15 MT drag radials. Weight of the car is 3880 and ran a 13.04 in the 1/4 when launching at 1800. with a 1.8 60 ft. I'm sure i can get a better 60ft.

[grivera]

Originally Posted by scooter1966

Here is my experience with the XE274 cam. Engine is a 455 40 over, 1.65 rockers, 6X heads that have been milled 20. Compression is at 9.2.The heads got the Jim Hand porting at home, but I only did the bowl work and did not touch the ports. 32 deg total timing all in at 3k. Th350, Continental "J.Hand" converter with 3.89 rear. 750 Holley on a Torker 2. 275/50/15 MT drag radials. Weight of the car is 3880 and ran a 13.04 in the 1/4 when launching at 1800. with a 1.8 60 ft. I'm sure i can get a better 60ft.

Mikes455Wagon went 11.7's with the XE274 and unported 62's

[Bentwheelbob]

Here's a stump puller combo...

It's in a stroked W72 for my 1978 Y88 Trans Am The engine is built to look completely stock with correct XX block, 6X heads, stock cast iron 10003395 intake, and correct 17056263 quadrajet. Len Williams provided the stroked short block XX, and Dave at SD Performance provided his full package 6X heads, the CNC'd and polished intake, and his Stump Puller cam. Cliff provided his top line rebuild kit spec'd for the engine and it proved dead nuts on. The lifters are PRW 1.52 rollers.

Yesterday morning it landed at Kauffman Racing to get broken in and dyno'd. Everything went great with no meaningful drama other than a small water pump leak and stuck thermostat. It came to life after the second bump and I am really pleased with the numbers and lack of issues that were encountered. They recorded peak HP of 474 at 5100 rpm on the 6th pull, and peak torque of 549 at 3600 rpm on the 5th pull.

[scooter1966]

Originally Posted by Bentwheelbob

Here's a stump puller combo...

It's in a stroked W72 for my 1978 Y88 Trans Am The engine is built to look completely stock with correct XX block, 6X heads, stock cast iron 10003395 intake, and correct 17056263 quadrajet. Len Williams provided the stroked short block XX, and Dave at SD Performance provided his full package 6X heads, the CNC'd and polished intake, and his Stump Puller cam. Cliff provided his top line rebuild kit spec'd for the engine and it proved dead nuts on. The lifters are PRW 1.52 rollers.

Yesterday morning it landed at Kauffman Racing to get broken in and dyno'd. Everything went great with no meaningful drama other than a small water pump leak and stuck thermostat. It came to life after the second bump and I am really pleased with the numbers and lack of issues that were encountered. They recorded peak HP of 474 at 5100 rpm on the 6th pull, and peak torque of 549 at 3600 rpm on the 5th pull.

Not to go off subject, but why is the A/F L1 very different than the A/F L2?

[Cliff R]

Another board member went mid-11's with the XE274 in a 400 engine, still a very poor cam choice for a pump gas 455 build at any compression ratio, IMHO. Some guys just have cars that are very well set-up to effectively use the power they are making, so can run good numbers with those parts, or just about any combination of parts that make decent power.

I also have a customer that runs well into the 11's with a 455 using the XE-274 camshaft and iron heads. His heads are very well ported, and bowls "hogged" extensively and 45 degree seats. Compression is pretty high as well, and he uses stamped steel rocker arms and light valvetrain components. This really helps as it doesn't take nearly as much valve spring pressure to keep things in check and avoid "lifter crash" at high rpm's. So his 455 revs well past 5200rpms and makes good power with the heavily ported heads. We see most of the XE cammed engines go "dead" early in the rpm range, even the ones I've had on the dyno are DONE by 5000rpms or so. I attribute this to the ultra quick seating velocities, and harmonics that develope at high rpms as a result. Instead of trying "tricks" to get those cams to work, we just pick better cams right to start with, that don't require extra spring pressures, super light valvetrain components, 45 degree seats and heavy bowl work, etc.

These excellent results with XE cams NEVER happen with the smaller ones, and even with the larger grinds fall into the same catagory as the guy that runs into the 10's with a completely stock fuel system and stock mechanical pump. For every guy doing that deal, there are 30 guys that can't get out of the 13's trying to do the same thing........FWIW......Cliff

PS: NICE numbers on the W-72 stroker build!

[grivera]

Originally Posted by 72LuxuryLeMansLa.

You want to define "big turd" for us? According to SD Performance "In a recent dyno test this cam installed in a 464ci engine with 9.5 to 1 compression, a set of our 250-260cfm CNC ported #11 cast iron heads, CNC ported cast iron Q-jet intake and a prepped Q-jet carb made 503hp and 575+ lb/ft of torque on 91 octane."

In my world 575lb/ft and 503HP does not equate to a "big turd" but is a respectable car. WE ARE in the street section after all.

Originally Posted by Bentwheelbob

Here's a stump puller combo...

It's in a stroked W72 for my 1978 Y88 Trans Am The engine is built to look completely stock with correct XX block, 6X heads, stock cast iron 10003395 intake, and correct 17056263 quadrajet. Len Williams provided the stroked short block XX, and Dave at SD Performance provided his full package 6X heads, the CNC'd and polished intake, and his Stump Puller cam. Cliff provided his top line rebuild kit spec'd for the engine and it proved dead nuts on. The lifters are PRW 1.52 rollers.

Yesterday morning it landed at Kauffman Racing to get broken in and dyno'd. Everything went great with no meaningful drama other than a small water pump leak and stuck thermostat. It came to life after the second bump and I am really pleased with the numbers and lack of issues that were encountered. They recorded peak HP of 474 at 5100 rpm on the 6th pull, and peak torque of 549 at 3600 rpm on the 5th pull.

I'm running the same cam so I'm glad to see your results. I am curious as to why it's down on power compared to the SD test...474 hp/549 tq vs 503 hp /575 tq

[Cliff R]

Most likely just not on the same dyno. KRE's dyno tends to be a bit "conservative", but when we remove the engines from the dyno and put them in a vehicle set up to effectively use the power, they ALWAYS deliver excellent results at the track....FWIW......Cliff

[screamingchief]

Originally Posted by ponyakr

What about the 744 RA3 stick cam. I've heard at least one guy really badmouth this cam.

Sigh...

I know I'm that "one guy",I even remember when & where that happened,but FYI Don I did'nt badmouth that 744 cam @ all,That's just how you reacted to being told something you did'nt already know.

See,the problem lies with the fact that you were recommending using that 744 cam to guys and telling them they could use "stock" valvesprings and pressed in studs and such,and all I did is inform you and anyone reading that thread @ PSP that was a bad idea,as even the factory used stiffer springs and screw in studs as SOP due to that specific cams lobe design and it's known tendency of being hard on valvetrain pieces.

That 744 cam has a lengthly background story that apparently you have no idea about.

You gotta stop being so hyper-sensitive to things like this Don.

I'm sure you're gonna wanna climb up on the cross after this post too...

But there's no valid reason for you react like that,as I harbor absolutely zero animosity towards you Don,I just like to see good info being passed along on these forums,and as such I will readily correct any subpar info being passed along as gospel,I do such just to help those other folks that dont know any better than to trust said subpar info/advice.

Have a nice day.

Bret P.

[ponyakr]

I just thought of a couple of more questions on the 744/2802 cams. Even tho the 2802 has a lot more lift, can it get by with less spring pressure than the 744, because of having a smoother profile, rather than the "bullnose" lobe, as someone described it ?

I assume this "bullnose" is similar to the NHRA Stocker grind profiles, just not as pronounced. Is this correct ?

What exactly was the higher spring pressures that Pontiac used on the RA3 and SD455 engines, with this 744 grind cam ?

The popular spring for many Pontiacs seems to be the Crower 68404's. So are these springs strong enuff for a 744 grind, or will it take something stronger ? Will they work on the 2802 ?

http://www.summitracing.com/parts/cr...3wrBoCKazw_wcB

[Steve C.]

I'm always curious why the Pontiac community often calls for or can be stuck on low valve spring pressure. Even to the point some get their panties in a wad over it, like the opposite is evil We even see this with aggressive XE lobes.

My old Crower catalog says the popular 68404 spring is rated 113 lbs at 1.600" IH. So what happens with a bit more, like many of the aftermarket cam companies often suggest. While touting adequate pressure these companies will always make a point and call for more not less pressure to control the valves.

Ok, the main disadvantage with higher spring pressures is that stiffer springs don’t last as long as springs with less spring tension.... but are we really looking for a 100,000+ miles of driving on most of these scenarios.


.

[ponyakr]

I've got another dummy question. I've read a lot about guys using 1.65 rockers. In my mind, using the laws of physics, or whatever, using 1.65 rockers will put more stress on the pushrods, lifters and cam lobes. I assume this, since more force must be applied to the short end, in order to apply the same force at the valve end of the rocker.

Since the force needed to depress the valve springs, is the same, regardless of rocker ratio, it makes sense that the higher the ratio, the more force required at the short end, to open the valve. Does this make sense ? Or is it ridiculous ?

Let me simplify it, with this question. Will using 1.65 rockers put more strain on the pushrods, lifters and cam lobes, than using 1.5 rockers ?

Why would it matter ? Well, if you're gonna put a lot of street miles on your engine, wouldn't less pressure on the cam lobes make the cam and lifters last longer ? I assume this would make a difference in how many street miles a flat tappet cam could last ?

I've read where some recommend breaking in a new cam with just the outer springs installed. Since there have been so many problems with cams going flat, even if you plan to run 1.65 rockers, would it be a good idea to use 1.5 rockers for cam break-in ?

[wovenweb]

Originally Posted by Ben M.

I just hear so much flak from people on how it's "old technology."

Old technology does not = bad technology. Only bad technology = bad technology.