# Pontiac Magazine 560HP build-up



## ml3126 (Jun 27, 2011)

hello. I am looking for any information on a pontiac magazine 455 560hp build around or before 2004. according to previous owner - The current 455 was purchased and rebuilt in 2004 utilizing the guide to a Pontiac Magazine 560HP build-up.
If anybody has or remembers this build I would love to read the article. I am debating going with the edelbrock heads. thanks

it has the following -

I chose to use cast-iron 1969 #62 casting cylinder heads ILO the Edelbrock aluminum RPM’s as mentioned in the article. The 455 however different by the differential in cylinder head spec. produces an immense amount of power. This motor has not been dyno tested however so the true horsepower and torque can only be speculated. I can tell you that this engine is healthy! This car is krazy fast and should be taken seriously when pressing the pedal to the floor...seriously!
a) Block: Tanked, bored .040 over and line honed
b) Pistons: Seal Power flat-tops with valve reliefs w/TRW rings
c) Rods: Stock- sized, balanced and honed with ARP studs
d) Crank: Trued and balanced
e) New bearings throughout 
f) Heads: Tanked, magna-fluxed, checked for deck true and machined for new Federal Mogul valves, guides, seals and Summit Racings “pro-series” rocker arm stud kit. Edelbrock RPM springs/retainers and ARP CH bolts 
g) Cam: Hyd. Competition Cams “Xtreme Energy” 284/296- 507/510 lift with *1.5 rockers.
h) Lifters: SLP heavy duty (standard bore)
i) Pushrods: Crane Energizer 5/16 x 9.170
j) Roller Rockers: Crane Energizer 7/16; 1.65 ratio (see g. above)
k) Oil Pump: Mellings 80lb. Hi Pressure
l) Timing Chain: Summit tru-roller
m) Oil Pan: Milidon gold anodized
n) 1. Intake: Edelbrock RPM with Edelbrock bolt kit 2. Carb: JET 800 cfm, Stage II, Quadrajet w/elect choke
o) 1. Fuel Pump: Holley 7lb. Electric 2. Inline filter and pressure gauge (see pics) set at 5.5 
p) Ignition: MSD Pro-Billet distributor, MSD 60,000v Coil, MSD-6A multiple spark ignition control module and Summit Pro-Wires high heat silicone HEI Blue.
q) Starter: Summit Pro-Torque 
r) Charging: A new 80 amp alternator was installed at time of the rebuild
s) Valve Covers: Summit Pro Tall’s/Chrome with Moroso breathers


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## BearGFR (Aug 25, 2008)

Your biggest problem is going to be static compression ratio, probably way too high for pump gas. Those #62 heads have combustion chambers with volumes in the vicinity of 72 cc's. Put those on a +.040 455 (4.190 bore, 4.21 stroke) with flat top pistions and "nominal" factory measurements everywhere else, and it'll be in the neighborhood of 11.5:1 static compression ratio. That "big 'ol" long duration cam wtih 1.65 rockers is going to help "some" (where's the intake lobe centerline installed?) but I'd be surprised if it was enough to keep this motor from detonating on 93 octane fuel.

87 cc Edelbrock aluminum heads would help avoid detonation in two ways: the larger chambers would put compression just over 10.0:1 and also run cooler. They've also got more peak power potential when ported by someone who knows how.

my .02

Bear


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## Thumpin455 (Feb 17, 2010)

Its going to be hard to pinpoint the article because they have done engine builders recipes and shootout combinations since the 90s. Its like finding a needle in a stack of needles.

That is a good build, will make great power and be scary to 90% of people out there. Its an underwear changer.

It wont live on 93, sure it will run on it, but it will not take much beating before something breaks. Only three ways around this; 

1: Change fuel to race gas/race gas mixed with pump, or run E85 if its available. 
2: Change heads to lower compression, such as the Edelbrock heads Bear mentioned, or some later big valve heads from 71-78 with larger chambers 
3: Dont drive it.

All of them require some changes, some more expensive than others. Where do you live?


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## ml3126 (Jun 27, 2011)

I live in Buffalo NY. Doing research I figured I needed to come down on compression. i am looking at butler perf. 87 cc Edelbrock aluminum heads round ports. Is there another performance company working edelbrock heads or do you think the stock heads are good? I am happy with the engine now so I am thinking of doing just stock edelbrock heads or is it worth the extra money to have them worked? thanks for the help.
i also see edelbrock has d port heads. Is one head(round vs d) better than the other. I want to buy new headers so it makes no differance to me.


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## BearGFR (Aug 25, 2008)

ml3126 said:


> I live in Buffalo NY. Doing research I figured I needed to come down on compression. i am looking at butler perf. 87 cc Edelbrock aluminum heads round ports. Is there another performance company working edelbrock heads or do you think the stock heads are good? I am happy with the engine now so I am thinking of doing just stock edelbrock heads or is it worth the extra money to have them worked? thanks for the help.
> i also see edelbrock has d port heads. Is one head(round vs d) better than the other. I want to buy new headers so it makes no differance to me.


Welll..... depends  Depends on what your goals are for the car, how you're going to drive it, and (always the biggie) what your budget is. Edelbrock's were the first aftermarket aluminum head and as such, lots of information is known about them and how to get them to make power. They aren't the only game in town now by a long shot, however. Edelbrock has very recently introduced a D-port aluminum head. There are others: Tiger, Kauffman, CV-1, repop Ram Air V,... not even sure I can list them all.

Out of the box the 87cc E-heads will make good power. It's been recommended to buy them 'bare' and then outfit them with your own valves, springs, etc. of much better quality than what they come with. If it were me, and if I wanted a "maxed out" set of E-heads (or any other head) I'd get with Dave Wilcox at Central Virginia Machine and have him build/port me a set ready to go. That shop is one of the best engine shops in the country and the folks there are honest people who'll do what they say they'll do. There are guys overseas in places like the Netherlands who won't let anyone else touch their Pontiacs.

With the foundation you have already in that motor, it'd be a monster.

Bear


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## Instg8ter (Sep 28, 2010)

i have that same cam out of a 455 i bought running it is loppy and mean sounding but does not start making good power until 2300 rpm and with it topping out around 6500 (1000 rpm higher than your redline with stock rods) most likely used it to keep the compression issues at bay. With 1:65 lifters that puts you around .557/.560 on lift also. with the head change i would find a cam that tops at 5500 and brings all your power curve into yoru rev range....maybe Bear can run a few simulation on his software and suggest a better choice for your intended uses....these motors are simply torque monsters i have a mild .454/.454 cam with the 1:65's and all else similar running 9.5:1 and with it not even fine tuned yet, if i stomp it at a 20 roll it will SMOKE the tires (with 4 people in the car) and a 2:56 rear gear.

Comp Cams #249-12-250-3
Xtreme Energy XE284H Hydraulic Flat Tappet Camshaft Only
Lift: .507''/.510''
Duration: 284°/296°
RPM Range: 2300-6500


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## Pontiacpurebrred (Jun 22, 2011)

Since I am also building a 455 I have been looking around at different write ups. 

Here is something interesting and a fun read. 

The 455-cu.in. V-8 debuted in 1970 and was the largest displacement Pontiac engine ever built for the street. It is likely also one of the best, said Jim Taylor, the legendary Pontiac engine builder from Phillipsburg, New Jersey. "I love Pontiac engines, and the engineers who built them were tremendous, absolutely at the top of their game," he said.

Taylor shies away from aftermarket stroker cranks to make power with a 455.

"When I build up a 455 engine, I use the original block and crankshaft, because that Pontiac crank is the best that was ever made," he said.

He admits Pontiacs have engine failures, but it's not because of the crankshaft, rather it is a failed connecting rod or rod bolt.

"I've never seen a nodular iron crankshaft break on a Pontiac," Taylor said.

Like all other American carmakers, engineers at Pontiac in 1970 were in a transition year as they saw tightening emissions standards forcing them to give up high-compression engines. High compression causes a spike in combustion temperatures, which enhances the buildup of nitrogen emissions. Along with emissions regulations, weight was increasing and the only other way to keep up performance was to increase displacement. The Ram Air IV 400-cu.in. V-8, with 370hp, could be ordered through most of the 1970 model year, but Pontiac intended the 455 to phase out the Ram Air IV, even though the RAIV could outperform a 455 in the quarter mile. For specific power output, Hanks believes the 1969-1970 Ram Air IV was the best Pontiac engine ever. "The factory rating was conservative at 370hp and later weight/mph calculations in quarter-mile performance indicate that the engine produced the rated power at the rear wheels," Hanks says. However, at part throttle, the 455's milder cam and smaller ports gave it better throttle response and the 455 was more adaptable to high-speed cruising. The 455 was also burly enough to handle all the power accessories, such as air conditioning, that GTO owners were beginning to order. In 1970, the 455 had the no. 64 cylinder heads.

"Cube for cube, carb for carb, when you put a Pontiac 455 on a dyno and add up the points, which are torque and horsepower, there is no better engine," Taylor said. "Power is all about torque. A Pontiac will pull away quicker and will put you back in the seat. A Pontiac 455 is more responsive than a Chevy or a Ford. In a Pontiac, the torque is most efficient in the rpm range in which you drive. A 400 Pontiac is not a torque maker. And a 428 makes torque, but nothing like a 455. The 455 SD is not the most powerful engine Pontiac built, due to lower compression. One point lost in compression equals 50-lbs.ft. of torque and 50 hp."

Taylor said the 428 engine is very efficient and has a good bore-to-stroke ratio. Pontiac kept its ports small and the 428 is one of only a few engines that had fully machined combustion chambers from the factory, which delivers exceptional cylinder balance.

Taylor maintains that a 455 produces high vacuum at idle, which leads to instant throttle response. "It gives you what you want when you hit the gas pedal," he said. "The 455 has relatively small ports for the size of the engine. In contrast, a big-block Chevy and the bigger Fords have huge ports and that isn't always the best combination for the street. A Pontiac engine has low cubic-feet-per-minute flow through the carburetor, but high velocity through the cylinder heads for more efficiency."

While Taylor sings the 455's praises, like the quality of the cast iron in the blocks, he reveals one major weakness--the lifter bores. "You can't put a big cam in a 455. The weakness is particularly in number two and number six cylinders. The cam tends to pick the lifter bore right off the block," he said. "The proper webbing can be installed if you know what you are doing, but because of this weakness I will not build, say an 800hp engine for a customer, and I absolutely refuse to build one with nitrous. I can build it, but with nitrous it just won't last."

Let's take a look inside a 455 V-8 and see what makes it tick, er, scream. Basically, a 455 is a 400 stroked 0.46 inches. The gross torque rating computed to 480 foot pounds and in 1971, GM rated everything net, so in reality the engine produced 410 foot pounds of torque at 3,600 rpm. This increase now meant the engine was oversquare, meaning the stroke was longer than the diameter of the cylinder bore (4.12 inches) which all adds up to a 5,500 redline. Because the 455 was an oversquare engine, Pontiac engineers used lighter parts in the reciprocating assembly to cut down on mass, which in turn relieved stress. For example, each piston now weighed 1.5 ounces less than in 1970, but at the same time, engineers worked to keep the engine strong by increasing the crankshaft's main bearing journals from 3 inches in the 400 to 3.25 inches in the 455. To further increase toughness in 1971, all crankshafts were cast of nodular iron, in contrast to standard cast iron, and the new 197 casting number heads retained screw-in rocker arm studs from 1970.

By 1972, Pontiac's 400-cu.in. V-8 topped out at 250hp, and the 455 Ram Air IV boasted 300hp despite its 8.4:1 compression ratio. The next year, Pontiac introduced the 455 SD, which put out 290hp in both automatic and manual transmission equipped cars. Considered one of the ultimate Pontiac engines, it suffered from an oil pump with extremely high pressure. In 1973, Pontiac tried to get around the new exhaust gas recirculation regulations (EGR). To accomplish this, engineers provided a solenoid within the system to render the EGR useless. They got caught and the Environmental Protection Agency required that the solenoids be removed.

In 1974, after America suffered through its first energy crisis, Pontiac offered the 455 SD one more time before the advent of catalytic converters in 1975. Thirty years ago, you could still buy a 455, but it was emasculated and breathing through a single exhaust and produced just 200hp at 3,500 rpm. Worse yet, the 400-cu.in. engine wheezed out only 185hp, a shadow of its former self. At least during the 455's last year in 1976, the engine still made 200hp, but performance for the brand was all but dead.


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## Pontiacpurebrred (Jun 22, 2011)

Another great write up - 
Pontiac 455 Engine Buildup - Hot Rod Magazine


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## Thumpin455 (Feb 17, 2010)

Well, living in Buffalo NY, you have a number of stations that carry E85. All you would need to run it is a different carb. No need to swap heads or buy new ones, change carbs, fill up at one of 6 stations in the area, more in Rochester, and enjoy the power of your engine without pinging or death rattles.

If you have a spare Qjet or Holley laying around and want to try it, mail it to me and I will send it back ready to go.


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## ml3126 (Jun 27, 2011)

I am pretty sure I am going with these heads ported. just not sure where I will get them from. Edelbrock Pontiac Performer Cylinder Head 455 D-port. Not sure which size to go with-72cc combustion chambers provide a 9.5:1 compression ratio when used with flat-top pistons or should i just get the 87cc for compression. I will also move down in cam size. i need more vacuum and to put the cam range with the engine. Anybody want to recommend a cam? Also should i stick with 1.65 rockers or go down to 1.5? thanks for all the help.


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## BearGFR (Aug 25, 2008)

ml3126 said:


> ... Not sure which size to go with-72cc combustion chambers provide a 9.5:1 compression ratio when used with flat-top pistons or should i just get the 87cc for compression.


Not to be picky, but it sounds like you've got it backwards. The smaller chambers result in higher compression, larger chambers - less.



> I will also move down in cam size. i need more vacuum and to put the cam range with the engine. Anybody want to recommend a cam? Also should i stick with 1.65 rockers or go down to 1.5? thanks for all the help.


Your choice on the rockers. 1.65's make the motor "act" like it's got a cam with a tad more lift and duration, so if you're swapping the cam anyway and not wanting to go "rowdy", I'd stay with 1.5's and just pick a cam that places lift and duration where you want with 1.5's. That way you won't have to bother with making sure the pushrod holes are large enough to clear the pushrods with 1.65's.

I've got software here that does a pretty good job of modeling engines, so if you'd like me to run some simulations I can do that for you. The more info, the better the simulation will be.

Bear


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## ml3126 (Jun 27, 2011)

Bear thanks for all the help. I am talking to Jim Lehart. He has been very helpful. thanks!


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## BearGFR (Aug 25, 2008)

Great! You'd be wise to trust what he says. Make sure you're honest with him about what you want the car to "be" when you're done and he'll take care of you.

Bear


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