# 421 sd engine power



## freethinker (Nov 14, 2009)

interesting video. what kind of power did pontiacs strongest showroom engine,the 421 sd, actually produce back in the day?


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## Koppster (Jul 27, 2008)

Stock 421 SDs ranged from 370 to 410 horsespower:

Pontiac Power


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## freethinker (Nov 14, 2009)

Koppster said:


> Stock 421 SDs ranged from 370 to 410 horsespower:
> 
> Pontiac Power


someone didnt watch the video.


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## Koppster (Jul 27, 2008)

Freethinker, I understood the question to be about factory ratings and if you click on the link you'll see I provided the correct answer. 

And, yes, I watched the video and enjoyed, if I had been guessing I would have guessed HP to be lower than factory rating and lower than Chevy...very nice surprise.


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## Instg8ter (Sep 28, 2010)

just shows that Pontiac engineers grossly under rated the HP well before the 70's. That SD would put a woopin on most anything stock that pulled along side it....and they proved it at the track.....arty:


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## Pontiacpurebrred (Jun 22, 2011)

Wow I knew they were strong, had no idea they were *THAT *strong. Veeeerrrrrry impressive.  And fuel to my wanting a 428 fire.


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## Thumpin455 (Feb 17, 2010)

Pontiacpurebrred said:


> Wow I knew they were strong, had no idea they were *THAT *strong. Veeeerrrrrry impressive.  And fuel to my wanting a 428 fire.


400, 428, 455, 496 whatever you choose, with the right cam and a decent set of heads it will run. I think my next one will be a 400 block with a 4.5" crank in it. That will make one hell of a fun street engine.


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## BearGFR (Aug 25, 2008)

Like Mr. PBody says... the GTO didn't gain its reputation by losing to SS/396...

Bear


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## geeteeohguy (Feb 2, 2008)

I have an old car magazine article from the '80's (heck---maybe even the late 70's) where they actually dyno'd a stock '62 421 SD Catalina. It was rated at 405 hp, but dyno'd out at something like 480+ during their test.


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## geeteeohguy (Feb 2, 2008)

Another thing, with Pontiac being conservative on their ratings and Chevy boasting about theirs, it was easy "back in the day" to beat Chevies that were supposedly superior....especially the 350-375 HP Chevelles and even the big, bad, 454's. Nothing like telling a guy in a '70 454 SS Chevelle that you just waxed him with a 389!!!!


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## 66tempestGT (Nov 28, 2009)

i dont know how much compression that 421 has but it is on your heels bear. stock 
just think what it would do with tri power. 

went back and saw the compression. not as high as i expected.


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## freethinker (Nov 14, 2009)

regular gtos werent that fast and available tires were a limiting factor. most ran mid 13s quarter miles.
i remember back in 69 during my high school days a nearby town had a pontiac delarship. the sons of this dealer had 3 matching 69 judges. a rivalry erupted between our towns about who had the fastest cars. a drag meet was set up on a back country road. my town had a guy that had a 65 shelby mustang with a 289 in it. the gto guys laughed at the mustang. they raced and the laughing stopped. they must have raced 50 times and that mustang beat the judges every time.
later i had a 68 gto 400 4 speed and my buddy had a 55 chev with a little 327 4 speed. that little chevy would beat me every time. i made a lot of noise and tire smoke but that is not what counted.


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## Pontiacpurebrred (Jun 22, 2011)

Driver mod? 

In my 68, which was not my fastest GTO - granted radial tires and an auto transmission (with a stock stall) - I never lost a "drag" or street race until I came up next to a very slick GTX. He schooled me. 

I have a great deal of trouble believing stock vs. stock that a mustang or a chevy with those motors were even in a class with a GTO, much less a Judge. 

If you can't launch the car properly that does not mean it's not as fast as the cars with drivers that know how to launch a V8 with some power. 

Not trying to start anything, and not saying anything, just from my experience anything other than a really light car (nova, vega) with a hugely over sized motor or built motor ~OR~ a 440 or 426 Hemi cuda or challenger or charger or gtx (and I still think they need to be built as well) can NOT compete with a GTO. NOW if you build a goat....look the hell out. 

Just say'n "from my experience"


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## Thumpin455 (Feb 17, 2010)

Back in the 90s the 70 GTO and 79 Formula both got beat often until I found tires that hooked. It was never a question of power because they would put about 5-6 lengths on me out of the hole, then once I hooked up I would catch them but not quite get around them. McCreary sells a tire for dirt track turn left cars that hooks anywhere, the circle track guys used to throw them away after three heats, right when they were perfect for drag racing. A couple sets of those and suddenly 11s were not a problem in the Formula. 

The chevy guys I used to beat on said my 455 sounded like I was going out for a loaf of bread since it shifted at 5800 and I left off idle. They always accused me of running spray because the fastest guy they knew had a 427 in a Nova with a glass front end and doors that ran 12.90s. They just couldnt imagine a 455 with ported heads, a mild cam, and a stock 13" converter was running 11.70s easily in a 3800lb car.

Even the 400s I had in my cars would stomp on most of them, you just have to build it like a Pontiac, not like a chevy. There was a guy in Charleston with an 80 TA that was running a 455, but he had 4.56 gears, a 4500 stall, and a [email protected] cam, and he had to spray it with a 250 shot to run with my mild engine. He was running 1/8th mile only but the gears still hurt him. You dont need much gear when you have a big thick flat torque curve from idle to 5500.


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## freethinker (Nov 14, 2009)

Pontiacpurebrred said:


> Driver mod?
> 
> In my 68, which was not my fastest GTO - granted radial tires and an auto transmission (with a stock stall) - I never lost a "drag" or street race until I came up next to a very slick GTX. He schooled me.
> 
> ...


dont forget back in the late 60s all we had was skinny bias ply tires. not the best thing for a nose heavy car like a gto. while it was easy to impress with 4th gear rubber on the street in a pontiac gto,that doesnt win races.
both the mustang and the chevy were a 1000 lbs lighter and they were leaf spring cars. leaf springs are much better for traction than that wheel hopping 4 link suspension the gto had.


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## Pontiacpurebrred (Jun 22, 2011)

freethinker said:


> dont forget back in the late 60s all we had was skinny bias ply tires. not the best thing for a nose heavy car like a gto. while it was easy to impress with 4th gear rubber on the street in a pontiac gto,that doesnt win races.
> both the mustang and the chevy were a 1000 lbs lighter and they were leaf spring cars. leaf springs are much better for traction than that wheel hopping 4 link suspension the gto had.


No I understand completely, the one and only time I drove a car with bias plys it took me several attempts to get a feel for how slick they were off the line. BUT, any goat (as referenced by Thumpin) will have traction issues. Like you said the suspension was not built with traction in mind, that said, feather the pedal, walk to roll and stomp it, you will get enough traction to to launch. Those cars are not in a class with a Pontiac 389-421 and the 50's and 60's race circuit and NASCAR proves it.


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## freethinker (Nov 14, 2009)

Pontiacpurebrred said:


> No I understand completely, the one and only time I drove a car with bias plys it took me several attempts to get a feel for how slick they were off the line. BUT, any goat (as referenced by Thumpin) will have traction issues. Like you said the suspension was not built with traction in mind, that said, feather the pedal, walk to roll and stomp it, you will get enough traction to to launch. Those cars are not in a class with a Pontiac 389-421 and the 50's and 60's race circuit and NASCAR proves it.


lol. while you are playing footsie the other guy just got 6 lengths on you and now you are playing catchup.
sure in the late fifties till about 63 pontiac was unbeatable but they lost their way and by 69-70 they were not competitive on race tracks.
i even attempted to race pontiacs circle track for a few years back in the 80s but they were not competitive. the 350 chev dominates local racing all over america. i finally switched to chevy and started winning races.


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## Pontiacpurebrred (Jun 22, 2011)

Well to each his own I guess.

Back on topic of real cars....all this talk of 421 Pontiacs I fell over this and I am oh so very tempted. This thing is just waiting for some love.
65 Pontiac 2+2


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## 66tempestGT (Nov 28, 2009)

freethinker said:


> dont forget back in the late 60s all we had was skinny bias ply tires. not the best thing for a nose heavy car like a gto. while it was easy to impress with 4th gear rubber on the street in a pontiac gto,that doesnt win races.
> both the mustang and the chevy were a 1000 lbs lighter and they were leaf spring cars. leaf springs are much better for traction than that wheel hopping 4 link suspension the gto had.


makes you wonder why people with purpose built race cars use 4 links instead of leaf springs. wheel hop is caused by spring wrap up and is not an issue with a 4 link. thats why leaf spring cars run snubbers.


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## Thumpin455 (Feb 17, 2010)

freethinker said:


> the 350 chev dominates local racing all over america. i finally switched to chevy and started winning races.


Well a big part of that is how the rules are designed to favor running a chevy in circle track classes. They want everyone to use roughly the same stuff to keep it even and everyone has a roughly equal chance. It also makes it easier to tech things when everyone has the same combo or a similar one, knowing what is up with a Pontiac is tough since to non Pontiac guys a 301 looks just like a 455. So the rules are biased to run a chevy, so its no wonder the chevy dominates the classes. At least that is how it was where I lived.

One thing about those roundy turn left guys, I sure got lots of cheap parts from them when they couldnt figure out how to make it work. 650-850 4150 carbs for $50-$100 that only needed a jet change to run right were all over town. I have a Carb Shop 850 I got for $75 that I still use and it works flawlessly where they couldnt get it to run at all. Maybe it was just the guys who lived near me that didnt know how to tune a carb, build a transmission, set up a rear end, or would throw away slightly used tires. 

Once I got some good tires there wasnt a 350 chevy that could hang with the Formula, and still drive around on the street easily. Good truck engines too!


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## Thumpin455 (Feb 17, 2010)

Pontiacpurebrred said:


> Well to each his own I guess.
> 
> Back on topic of real cars....all this talk of 421 Pontiacs I fell over this and I am oh so very tempted. This thing is just waiting for some love.
> 65 Pontiac 2+2


If I didnt have two 65 A bodies in the works right now, and three 71 Pontiacs with two 72s waiting, I would so pick that up. Always wanted a 65 2+2, that would be freakin awesome.


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## Pontiacpurebrred (Jun 22, 2011)

Thumpin455 said:


> If I didnt have two 65 A bodies in the works right now, and three 71 Pontiacs with two 72s waiting, I would so pick that up. Always wanted a 65 2+2, that would be freakin awesome.


Is that thing not sweet, man I wish I had the scratch sitting around. But right now Marilyn comes first.


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## freethinker (Nov 14, 2009)

66tempestGT said:


> makes you wonder why people with purpose built race cars use 4 links instead of leaf springs. wheel hop is caused by spring wrap up and is not an issue with a 4 link. thats why leaf spring cars run snubbers.


racing four links are not the same as the gm a body setup. the a body rear end suspension was a horrible design. it has to do with where the 4 links attach. google it.
in any case we were talking about what was available back when gtos were new. for someone to say that the gto never had wheel hop problems make me scratch my head.
i have owned over 20 gtos and have raced,repaired and tweeked gtos for over 40 years now. i worked for a pontiac dealer as a mechanic back in the early 70s. i have a restored 66 tri power and a 70 ram air 4 in my garage right now. i think i have a good handle on what these cars were and are capable of.


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## Thumpin455 (Feb 17, 2010)

Ive never had a problem with either the 70 nor the 72 and wheel hop. Both have had 400s and 455s in them, and only the 70 has a swaybar. I know you can have issues with it, changing the instant center can fix it, I just havent had a problem with it. Might be a ride height, tire, or shock issue too, but I can see how someone would not know about it. Might be a weight transfer issue too, I know the 70 doesnt like to lift the nose much.


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## 66tempestGT (Nov 28, 2009)

:agree i have a yard full of a bodies and have been drag racing an elcamino for 15 years. a guy would have to know what the instant center is for him to take advantage of that information.


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## likethat (Oct 5, 2007)

Thumpin455 said:


> McCreary sells a tire for dirt track turn left cars that hooks anywhere, the circle track guys used to throw them away after three heats, right when they were perfect for drag racing. A couple sets of those and suddenly 11s were not a problem in the Formula.


28.5 11.00r15. I use to go to Charlie Sentman auction around the mid west he died back in 2007. Charlie Sentman auction new promoters site That is the new auction. I picked up all kinds of big and small block chevy engine parts, tires, clutches and so on there for pennies an the dollar. I got 2 of these tires new for $50 for the pair. $25 dollar each is cheap to go out and burn them up. I had a friend that would give me Hoosier dirt track tires after every season for free. You could get a set of 8 6" rod JE forged pistons for a 30 over 350 for under a $100. That looked as good as new. 95% of the engine stuff was small block chevy.


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