[gman598]

ok, I've read through mountains of post on this site and every time I decide on a cam shaft, I read another post that changes my mind. Monies have freed up and I want to start working on this ride.

I own a 73 455 T/A, with a 72 455 out of a bonni.

currently; 72 455, 7m5 heads, Quadrajet, 400turbo trans (w/2800 stalh speed), 3:23 rear end.

I want to convert to a roller cam to avoid the additive hassles. Could someone help fill in my blanks. Now much like everyone else here, I don't want a drag strip car. I want a great running street able pump gas car with pep.

this is what I'm planning on:
"1972" - 455
6X-8 heads (new springs/seats, not planning on porting and polishing)
Ram Air 3 exhaust manifolds
Quadrajet (no plans on changing)
400turbo trans (w/2800 stalh speed), (no plans on changing)
3:23 rear end

CAM Choice: ??? (I was thinking RAM IV roller equivalent, but then I
read my 3:23's would not be enough to utilize the CAM)

[pontibeast]

Based on some of the help I received on my build I would say you might want more compression than the 9.0-9.1 you will have with your heads. I'm sure plenty of others will give you some better advice than I am capable of. I ended up going with the stump puller cam from SD Performance. I don't know when you are getting yours together but I will post dyno numbers once mine is done.

[gman598]

Thanks for the reply, Pontibeast

I've entertained that cam as well (I have it bookmarked), I've asked SDperformance this very question and I'm still waiting on an answer from them.

this is my ride currently; http://youtu.be/bzNCD_rFyIE

Someone here will recognize this ride because I bought this car from a board member.

[Will]

With stock heads and your gearing/compression/etc. it's best to stay a little on the conservative side.

That said, rollers are like solid flat tappets in that they behave like a smaller cam (when compared to traditional hydraulic flat tappets) at idle & low RPM.

I would think a cam with no more than 230 @ .050" duration and lift appropriate for whatever valvesprings are available for your installed spring height on a 112 LSA would be right in the ballpark. I think the Stump Puller from SD fits the bill here but check with Dave to be sure you can get springs that will work with it.

This is essentially a RAIV equivalent roller but it will idle smoother, have more low end grunt and pull more vacuum. 3.23 gears and a 2800 converter are fine with such a cam, and are in fact a great street combo for 455s.

[gman598]

Thank you WiLL!

[ponyakr]

The Kauffman HR230 looks like the specs ya'll are talkin. 230/236/112LSA

http://www.krepower.com/Pontiac%20Ca...nd%20Parts.htm

Butler can also order it, with any LSA you want.

http://www.jbp-pontiac.com/products/...compcams3.html

Don't know what the price is, ordering direct from CC. ?

Or, how about a 4/7 swap cam with 227/237/110 LSA ? --$350 shipped

http://www.summitracing.com/parts/hr...w/make/pontiac

[Steve C.]

Do you know your verified valve spring pressure ? Is it up to par for a roller lobe ? As eluded to by Will you had better know your current spring package and the current verified installed height in conjunction with the net valve lift involved. What rocker arm ratio ?

A wider lobe separation and lots of seat timing (advertised duration) will not help a low 9:1 compression.

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[gman598]

SteveC.

Once I give my guy the Comp Choice Spec (which he recommended the Ram IV as well) then he will replace the Springs/Retainers/seals to the stock valves accordingly.

[gman598]

SteveC

Rocker Arm Ratio, guessing the standard 1.5, or would I benefit from 1.5 intake and 1.6 exhaust?

BTW you have haven't figured out by now, my mechanical knowledge of building engines is not the high. Just tallying all the different things I read on every board mixed with some past engine tinkering.

[pontibeast]

If you do a search on mixing up the rocker ratio I just went through that question myself and for some very good advice. I don't know how to link it here but it should be easy to find. I found the best way to get ahold of SD is email their tech line. Dave was very helpful and patient with me as my combination changed along the way.

[promptcritical]

What's wrong with the motor already in the car? Sounds pretty hefty.

[Will]

Originally Posted by gman598

SteveC

Rocker Arm Ratio, guessing the standard 1.5, or would I benefit from 1.5 intake and 1.6 exhaust?

BTW you have haven't figured out by now, my mechanical knowledge of building engines is not the high. Just tallying all the different things I read on every board mixed with some past engine tinkering.

I wouldn't mess around with rocker ratio. If you have stock length valves your spring height is limited, you simply can't run a whole bunch of lift. Stick with stock ratio rockers to keep things simple - for the kind of engine you're building you'll never see any difference in performance messing around with rocker ratios. Your cam choice will make a far bigger difference.

Whoever you buy the cam from - KRE, Butler, SD, etc. let them know you're running stock length valves and buy a matched spring from them also. Again, keeping things simple. They'll know what springs will work with the cams they sell at a given installed height. Even so, best to double check things so get their recommended seat and open pressures and have that checked once the springs are installed. Also verify your coil bind height and retainer to seal clearances.

I have the world's worst luck and it has taught me to verify EVERYTHING.

[gman598]

Originally Posted by promptcritical

What's wrong with the motor already in the car? Sounds pretty hefty.

I want to convert to roller cam so I don't have to worry about the ZDDP add.

Then I can gain a quasi easy 40-50 hp just for adding 6x-8 heads (from what I've read) I currently have 7m5 heads which yields me around 7:2/4 compression again from what I've read. So if I'm going to change heads I might as well put a decent cam in it.

I'm putting ram air 3 exhaust manifolds because I rememeber the horrors of headers on my "77" t/a back when I was 17. Low clear/hot as balls inside the car/ and just baked all my starters solenoids.

The guy I bought it from told me that's a stock cam. I'm not really skilled enough to disagree with him because I know for a fact he knows what time it is when it comes to Pontiac engines but it doesn't sound stock to me.

[Will]

A stock '72 455 would have 8.2:1 compression and be rated at about 250 HP. - I'm assuming your engine out of the Bonneville is still stock.

You'll get a little bit of a power bump from raising the compression if you changed nothing else, maybe 25-30 HP at most. The important thing about raising the compression is that it will allow you to make use of a much bigger cam. The cam in that stock 455 is tiny. Combining the compression bump with the increase in cam should net you 100 HP pretty easily. You'll need to retune the carb for best performance and if the distributor is still all stock there are improvements to be made there, too.

[gman598]

Yes it's out of a bonne and stock.

Distributor is quasi stock. It has the some kind of electronics inserted where the points used to be. So it looks bone stock but there are no points.

Btw thank you for all your and everyone's help.

[b-man]

A 455 with 9:1 compression, stock 6X-8 heads, a RAIV-ish roller cam and 3.23 gears will be an absolute beast on the street.

I ran an old, never-rebuilt '74 455 with 8.6:1 compression and a bigger cam than the RAIV, the H-O Racing HC-03 (244/252 @ .050",.550"/.554" lift) and it ran just fine.

[Will]

Originally Posted by gman598

Yes it's out of a bonne and stock.

Distributor is quasi stock. It has the some kind of electronics inserted where the points used to be. So it looks bone stock but there are no points.

Btw thank you for all your and everyone's help.

Sounds like a pertronix kit. Regardless of whether it's points or electronic trigger the important thing is the curve. You can pick up a lot of performance with the right advance curve.

I think/hope everyone's goal around here is to see every Pontiac living up to its potential!

[Steve C.]

If interested in around 230 degrees intake duration.

Lunati Voodoo #20510712
282 / 290 advertised duration
231 / 239 @.050
110 Lobe separation
.530 /.550 lift
66 degrees overlap
Retro-Fit Hydraulic Roller. High performance street cam. Likes upgraded intake, carb and exhaust. Needs 2800 RPM stall converter in most cases.

Comp Magnum Hydraulic roller lobes 3111B & 3122B
286 / 289 Advertised duration
230 / 236 @.050
110 lobe separation
.565 / .570 lift
67.5 degrees overlap

Comp Xtreme Energy Hydraulic roller lobes 3194 / 3196
281 / 287 advertised duration
230 / 236 @.050
110 lobe separation
.584 / .586 lift
64 degrees overlap


Valve lift indicated presumes a 1.5 rocker ratio. When you start looking for a valve spring package I will suggest in order to provide adequate valve spring pressure for these lobes you will find at least a 1.700" installed height will be desired. Plan accordantly with your valve length for that. If you call Comp and they regurgitate the use of their 995 spring....run away, your going to want more pressure in my opinion. Note the valve lift will vary slightly depending on if its ground with a 51-00-11 part number or a 51-000-9 part number.

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[Steve C.]

Conversation on spring pressure...

137/305 pounds would be what I would use for a baseline on a mild Voodoo hydraulic flat tappet cam. Definitely not enough for a hydraulic roller cam. Cam manufacturers tend to always lean on the light side for spring pressures. A little more is way better than not enough.

http://forums.maxperformanceinc.com/...oo#post5528569

And if you look similar discussions can be found regarding adequate spring pressure in conjunction with quick opening and closing Comp hydraulic roller lobes.

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