Ad Radar
High Performance Pontiac
Click here to find out more!

Balanced or not?

  
High Performance Pontiac
Item Posts    Sort Order

Balanced or not?

 
Mace1971 Mace1971
New User | Posts: 5 | Joined: 07/14
Posted: 07/22/14
11:43 AM

I purchased a 71 T/A a short bit ago with a non-numbers matching rebuilt 2bolt 455 block with TH400. I do not have any details regarding the rebuild (i.e., block decked, balanced, ARP bolts, rods, etc.) but going over what I can see I'm curious if other, much more informed, Pontiac experts think the components are balanced (i.e., do they make sense?) I'm sure the Performer manifold was chosen to keep the functional scoop and the cam is matched to that manifold (per Edelbrock.)  It runs well enough (hasn't been dynoed) and I'm not looking to race but I'm curious if there's a significant amount of performance being left on deck here that I could easily pick up because it sure seems to me that the intake and cam are really limiting the potential.

Q-Jet (750cu/ft)
Edelbrock Performer intake manifold
HEI ignition with Accel supercoil
Edelbrock Perfomer RPM heads (advertised 72cc with 1.5 rockers, round port)
Edelbrock Performer Plus flat tappet cam (LSA 110, Advertised Duration 278/288,@.050 204/214
Hedman Husler ceramic coated headers:  1 3/4" primary / 3" collector
3" dual exhaust with 40 Series Flowmasters  

shyrgfuh3 shyrgfuh3
Enthusiast | Posts: 475 | Joined: 11/13
Posted: 07/22/14
02:20 PM

hello;

you will get at least 30 more hp with the rpm intake.

they make a low profile air cleaner so you can run the rpm on a shaker car.

tun as much timing as you can at 1600 - 1800 rpm.

connect your distributor vac line to ported vac, not manifold vac.
.
.  

Mace1971 Mace1971
New User | Posts: 5 | Joined: 07/14
Posted: 07/22/14
03:39 PM

You're thinking 30hp with just the manifold switch and keeping the Performer Plus cam or changing that out for a bigger cam such as the Performer RPM?  

Mace1971 Mace1971
New User | Posts: 5 | Joined: 07/14
Posted: 07/22/14
03:46 PM

.  

shyrgfuh3 shyrgfuh3
Enthusiast | Posts: 475 | Joined: 11/13
Posted: 07/22/14
03:50 PM

i have no idea what i am doing.  

shyrgfuh3 shyrgfuh3
Enthusiast | Posts: 475 | Joined: 11/13
Posted: 07/22/14
03:50 PM

up to 30 hp with a manifold change  but a ton more with a cam change especially if you have flat top pistons.

do you want top or bottom end.

bigger can means less bottom end but more top end.

the bigger the cam, the numerically higher the rear gears must be.

your current cam is kinda girly, lol.

this will wake it up but is not obnoxious.

http://www.lunatipower.com/Product.aspx?id=1777&gid=287


this is kinda nasty and bordering on obnoxious. shove it in there, your compression is plenty high enough if you have flat top pistons and not dished ones. toss in some 3.55 - 3.73 gears, a 2400 stall converter and be scared.

http://www.lunatipower.com/Product.aspx?id=1778&gid=287

an msd 6al-2 box will also help.  

My71 My71
Guru | Posts: 1252 | Joined: 02/10
Posted: 07/22/14
05:48 PM

Hey Mace,
Shy is right in that the performer RPM manifold is better suited to your heads so in that respect, yes you are leaving HP/torque on the table. Now given the breathing needed by a 455, a performer RPM matched to Eddy heads doesn't beath as well as  say the same combo on a 400. Typically on a 455 you can go up in breathing capability (intake/heads/exhaust) as a 455 takes a little more than a 400 just because of the stroke/bore ratio. I.E. a cam/intake/head/exhaust set up on a 400 that is considered to operate in the higher RPM ranges would be one step down (mid range) on a 455 as a general rule.
port/gasket matching will help a bit also on top of better breathing  manifold/heads/exhaust.
Your 455 is a two bolt but do you know the year of manufacture? Anything mid 75 and later has weaker webbing structure to save on weight so I wouldn't consider it a high revver. Best to look at torque and stay on the bottom end of the RPM range (<5500 RPM)
The gear swap will definitely help.
Only way to know if it's balanced or not is to have a machine shop look at the rotating assembly. If it's an automatic trans then there won't evne be a mark on the fly wheel for the pressure plate.
Just 2 cents worth of thought here..  
Jim,

bigD bigD
User | Posts: 142 | Joined: 05/14
Posted: 07/23/14
12:17 AM

On this forum, as on most others, you'll get different opinions on just about any subject you name. So, this is my opinion and I'm sure others will disagree.

The cam is definitely too small. The smallest cam I'd recommend is a RA4 duplicate. Most cam makers have their version of it. The Crower # is 60919.

http://www.summitracing.com/parts/cro-60919?seid=srese1&gclid=Cj0KEQjwur2eBRDtvMS0gIuS-dYBEiQANBPMRz_8TctKZiV-dM4uTri-Y12FNyuyKWk48hwS4Gj3-7AaAial8P8HAQ

I always bought the Melling # SPC-8. They are cheaper--usually around $100. The cheapest price I can find right now is from Auto Zone online. It's $93.99 + tax.

http://www.autozone.com/autozone/parts/?counter=0&filterByKeyWord=SPC-8&fromString=search&isSearchByPartNumber=true&itemIdentifier=311995&CJPID=3468012&cmpid=cj

Now here is where many disagree with me. Since the 70's I've used nothing but Rhoads lifters in all my Pontiac motors. They will make this cam idle smooth in a 455, and make about 500ft lbs of torque at around 3000rpm. In our bracket cars they would leave hard from an idle with a stock 13" converter, pull hard to our 5000rpm shift point, and run mid 12's consistently. The only negative that some see with the Rhoads lifters is the "ticking" sound they make below 3000 rpm. Sounds similar to a solid lifter tick. Some can't stand it. Summit always has the best price I can find for Rhoads lifters.

http://www.summitracing.com/parts/rhl-9518/overview/make/pontiac

With all the low end torque of the 455, a dual plane intake is not needed. A single plane will work just fine. I recommend either a used Torker 1 or one of the Cheap Chinese single planes. Ebay usually has some Torker 1's for sale. Some are cracked and have stripped threads. Others seem to be in real good condition.

http://www.ebay.com/sch/i.html?_odkw=&_qfkw=1&_ssov=1&_osacat=36474&_fln=1&_trksid=p2045573.m570.l1311.R1.TR2.TRC1.A0.H1.XPontiac+torker&_nkw=pontiac+torker&_sacat=36474&_from=R40

You'll notice that in the above link there are both Torker 1's(#2720) and Torker 2's(#5056) listed. If you plan to use a Q-jet carb, you need the #2720.

The Chinese single planes come in satin or polished versions. Ebay always has the best prices on these. They are only about $150--sometimes less.

http://www.ebay.com/itm/Pontiac-326-350-389-400-421-428-455-Shootout-Intake-Manifold-Satin-/201120743185?pt=Motors_Car_Truck_Parts_Accessories&hash=item2ed3baff11&vxp=mtr

http://www.ebay.com/itm/Pontiac-326-350-389-400-421-428-455-Shootout-Intake-Manifold-Polished-/181454996991?pt=Motors_Car_Truck_Parts_Accessories&hash=item2a3f8f85ff&vxp=mtr

Here's one of the polished intakes on a friends '69 Bird. It's got E-heads, a solid roller cam and probably makes well over 500hp. He drives it to shows and cruises.  Smile

100 2122 Zps6fec586a  

Mace1971 Mace1971
New User | Posts: 5 | Joined: 07/14
Posted: 07/23/14
05:41 PM

Thanks guys, you've given me a lot to think about. For My71, the block's a late YC coded '72 with a casting code of 485428 so don't think there should be any strength issues but Shy, yes, I agree the current cam is indeed "girly" lol.  I've got a lot of other things to take care of right now so I'll probably start with just the manifold and drop air cleaner.  That'll give me more time to really think about the cam because of all the other related things you guys have pointed out like the 3.08 rear end and lifters.  Moving too quickly may take some major negotiations with SWMBO (She Who Must Be Obeyed)!