Cam selection. Come on you know this is important......put in your 2 cents!

T

troys66

Member
Hey fellas,
Its been awhile. My computer took a little spill of my bed while visiting New London awhile back and I finally got if fixed up. In any case, Ive been collecting parts for my 455 and I have come to a cross road in my build. I have selected the TA performance SP1 intake manifold and will be running the stock exhuast header (slightly ported). I will aslo be using an edelbrock 750 carb. I will not be upgrading to the larger stage 1 valves. I dont see the the benefit outwaying the cost at this point, especially since I wont be upgrading the exhaust manifolds. If I was that would make more since. Maybe some one can convince me otherwise. The valve and exhaust upgrade alone would increase the cost of the build 1k. I do have a nice set of 23 cc dish pistons and after a little machine work I am looking at a compression ratio of around 10.5-1.

Now the question. I want an agressive cam for sure. Something barely streetable. A rough lopey idle, but wont stall out. The one I am looking at follows. I think it will allow me to get good preformance ont the weekends and accept some major improvements in the future. I also wanted to run the Rhoads lifters with it. Any opinions? Do I want too much?


Product ID: TA_288-92HProduct ID: TA_1415
RHOADS LIFTERS
Rhoads lifters are an ideal lifter for the Buick engine where rough idle, low fuel economy and poor driveability are the results of a larger cam. Rhoads lifters give the illusion of running two different cams at the same time. The lifters “bleed down” at low speeds through an oil orifice to make the cam act smaller than it is. Then at higher RPMs the lifter expands to let the cam be it’s actual size.




455H.525"-231'/.525"-234',110'
“The Car Craft Shoot Out Winner” Made 560 HP with TA Stage 2 heads on pump gas. TA roller rockers and valve springs recommended. 2500 -3000 stall converter recommended. Power Brakes ok. Fair Idle. 9.5:1 or more CR
VALVE LIFT
  • STOCK 1.55 RATIO:
    IN: .508”
    EXH: .508”
  • TA ROLLERS 1.60 RATIO:
    IN: .525”
    EXH:     .525”
DURATION

  • AT .050
    IN: 231
    EXH: 234
  • ADVERTISED
    IN: 288
    EXH: 292
  • LOBE CENTER: 110
  • POWER RANGE: 2000-6000
 
455 cam

First, why get a rough uidle cam and smooth it out with roahds lifters? Seems like defeating the purpose pf the rough idle.
Second, one of the weak points of the big block Buick is the exhaust flow. Thats why the cam has more duration on the exhaust side. Headers would be worth the extra money spent and bigger valves would also be very much worth the cash outlay. With all those inches you need to let the engine breath.
 
I had Rhodes lifters in the BBB at one point and took them out. It was like having 16 valve taps at idle. They will not enhance performance considerably since they are only effective below the stall RPM of the coverter necessary for the cam. They would help with idle and in gear idle, but you can set both of those higher to compensate without the tap, tap, tap.

The cam you selected (as HJ pointed out) does not have much of a split between exhaust and intake duration. It did well in the stage two heads (as listed). The stage two heads have better exhaust ports and flow. This means they do not require as much split in the cam durations. Your set-up will need a cam with more split in the duration, and stock exhaust manifolds will further increase the split needed.

Springs and rockers will also limit the cams that you can use. There are some good split pattern cams that you can not use with stock springs and rockers. Any change that vastly improves performance almost always requires supporting changes to maintain it.
 
Ok. You guys are starting to make me change my mind about the whole valve upgrade, and I was iffy on the whole rhoades lifter anyways.

How much will a machine shop usually charge for the machine work on that?

If I upgraded the valves what would be a good cam for my build? I am currently using the stock rocker arms. I have heard that on some applications that should be upgraded, but in my opinion the rocker arm set up on a Buick is far better than a Chevy set up.

Thanks for the feedback.
 
I agree with all that has been said, I guess you don't want/have a/c.

I do use rhoads and kinda like them, but I like a good idle (works with a/c) with the ability to run higher rpm, that's where they can work.

Glad you like the changes, more to come.
 
Chevy lifter conversion?

:waving:

Its been a little while, I did decide on the TA 290-08. Best cam for me, but I'm leaning more to the side of the solid lifters now so a cam change may be in order. Anybody remember where I can find Chevy rockers adapters for my heads?

Its nice to be back!
 
Basic set up.......

Pard, you would be better served to slightly ''under cam'' and go with a good free flowing exhaust system... and I aint neccessarily talking about headers... on the street a set of stock exhaust manifolds properly prepped will work as good as headers untill you reach the very upper rpm ranges... but 99% of the time you drive below that level....Buick has always made and put good designed exhaust manifolds on their engines ... and you dont have to hassel with the rubbing, ratteling, bending, cracking, rusting, leaking, that headers do....big exhaust pipes , yes,, big mufflers, yes,,, and so on.....
 
troys66 said:
:waving:

Its been a little while, I did decide on the TA 290-08. Best cam for me, but I'm leaning more to the side of the solid lifters now so a cam change may be in order. Anybody remember where I can find Chevy rockers adapters for my heads?

Its nice to be back!
Click to expand...

Switch to the TA 290-08R which is the solid roller cam version and use the TA Adjustable
Roller Rocker Arm assembly.
 
You have many mis-matched components on your build. You can spend a ton of money, and won't get the gains you might be wanting. You would be FAR better off to buy aluminum heads instead of a roller cam, and would spend about the same money. And, without headers, you can flow the exhaust out anyway. You also need a larger carb.

As far as cam goes, we are running low 10's and still running hydraulic cam.

Take the time to back up, match all of your components and you will spend less, and perform better.

my .02 worth.
 
Thanks for the tip on the exhast manifolds. I was looking at headers as an option and I have heard conflicting claims about the performance achivements. I am getting the heads ported and the stage 1 valves installed so that should help moving some air and fuel through the block.

At the begining of this project I had many ideas about what I wanted and it was based mostly on what I read. I have relized that there are many different opinions, all of them helpful but it can make it difficult to decide on which way to go.

What I do know is that I have my heads getting ported and stage 1 valves. The heads were 68cc, but will more than likely be smaller after the valve install (I will measure them out). I have the 23cc dish pistons. I will be using the SP1 Intake and the TA 290-08H. The adjustable roller rocker arms are just to expensive, and I could see better performance with money spent else where.

As far as the carb goes I think the holley setup looks racier, but the Edelbrock requires less attention. Thats one thing about the holley it always seems to need adjustment. So an 800CFM Edelbrock is my pick.

I have relocated the Oil sending unit to the rear of the block and the Oil passage Mods have been completed. Also, had the blocked decked.That stuff just made since to me.

All of this cost ahellofalot more than my old chevy blocks.

I just want to have a good time at the track on the weekends. If you can think of anything else that would improve my performance, Please let me know. Thanks for all the useful info.
-Troy
 
Theres been a few changes yet agian with this build. I scored a set of 2" Kenne Bell headers, and the TA performance intake is out the window because of a deal that was impossible to pass up. I also went from the edelbrock to a Holley 850 Double pumper. I have a 750 as well, so I figured I could mess around with both and see which one performs better. The cam will still be the TA 290. I also got the Stage one valves, so off to the the machine shop with those.
Anyone have any valve spring recommendations besides TA? Just curious.

Oh and the intake is an Offy, plus i SCORED an HEI distributor.
 
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Things are looking better for you. I would uses the stock manifold before the offy. They are known to flow poorly. I think you will find the 850 wors better for you.
 
I've run a holley hp 870, 850, 850 dp.... the 870 with the lightest vacuum secondary spring works best - be sure to upsize the rear jets if you run that same carb.

I've been agonizing over the decision on heads as well - I'll be interested to hear how this runs. my 2c is the aluminum heads at 2300 seems the better deal when the cost to upgrade to stage 1 valves is 1200-1400 not including the price of the heads. However, you have Rocket machine down there.... so head work would be much more affordable.

forgot to mention .... I have a 71 455 with offy intake, headers, stock (I think) cam.... runs 12ishes
 
I think iron heads are just as good as aluminum. I've done a little research and it seems as if the iron heads flow just as well as the edelbrock aluminum heads. The TA heads flow just a little better, but not by anything significant. In my opinion if weight is a big concern aluminum heads are beneficial but you sacrifice the strength and durability of the iron heads. I'm sure many people may disagree. To me the weight isn't much of a concern. The cylinder heads contain more moving parts than the rest of the block, so I'll keep the iron ones and modify them. I have 230 dollars tied up in valve train and the machine work cost me 400 bucks. So for 630 dollars I have ported stage one iron heads that will flow much better than the aluminum ones that would still need some machine work to get them up to speed. Not bad in my opinion. Much better than 2200 bucks.
- Troy
 
I agree with all of what you've said, although, there is another cost - the valve train - to upgrade to the TA performance (adjustable) is $759...

Conversely, there is an additional advantage, though, for cast iron - they hold better under boosted or NOx applications. While it is true that aluminum absorbs heat better, it doesn't have the strength of cast.... and on 4 bolt heads, that's a big deal.

as I said, been agonizing over the decision.... somewhere there is a thread where I've been discussing a turbo application and we kind of went over the induction setups

Also, I've built headers and they aren't that difficult to do.... if you want, I can recount my header build on here. (costs less than 200.00 to build)

you do have me curious, though, you mentioned there's an adapter to put chev rockers on a Buick head? who makes it?
 
Chevy rocker arm conversion

Yeah there are a few people who make them but Ive forgotten where exactly. You can also make your own if you modify your shafts and add studs. I personally like the shaft style rockers. I was curious if any other shaft style rockers could be machined to fit on the buick shaft?

If anyone remembers who makes the conversion for chevy rocker arms please post.

You should share your headers with us.
 
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