Hopping Up Pontiac Straight ''8''

HOLLY CRAP!!!!!!!!!!!!!! IS THAT A STRAIGHT 8 IN THAT RIDE?!!!!! I DONT NEED TO HAUL ASS LIKE THAT, BUT IT'S NICE TO KNOW THE POSSIBLITY IS THERE FOR IMPROVEMENT.
THANK'S FOR THE VID, VERY COOL.

Buzz Bomb

 

I will have some more / better pics up soon. But here is a little slideshow I had put together. the car has naturally aspirated setup and a turbo set up.

With non blown, one of the problems is fuel distribution. The engine is so long with only one carb the end cylinders run lean. The two carb set up works well. Check out the pics with the two carbs. Really, anyone can just get some tubing, weld it up, and a la duel carb set up. Of course length and diameter of the tubing will affect the set up. bigger tubing for high rpm driving.

If you want your 8 to go fast cheap, just get some tubing, a 4 barrel Holley, pull a turbo off some wrecked car, make the exhaust out of tubing, just weld it together to come to one big pipe which will run through the turbo and spin it to force the air through a pipe that goesw to the Holley, just use sheet metal and tubing, then the big tube splits to 4 smaller tubes to feed the 4 intake ports. Yes there is a little more to it, but not much. If you find the scrap tubing, an old carb, and a junk yard turbo, you could have a custom blown straight 8 in a long weekend of work and a couple hundred bucks to free if you are a good scavenger. With a blown application the forced induction makes it not matter much how long the pipes and tubing are, or if the bends are really straight or not kinked.
Go for it.
Wil
www.sakowskimotors.com
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I have seen this topic pop up about 3 times since I've been watching this forum, so I guess I'll share what little I know.

I currently have a poncho I8 as a project for the future. I have researched, asked questions, and have not seen many things done to them. Mine came from a 50 Pontiac. I wanted to put a turbo on it, but found out that up to a certain year, I believe it's 51(I could be wrong), the motors have a low pressured oil system. One could still do it if they wanted to with a inline oil pump($$) or something else. Just do your homework.

Anyways I will include some pictures that I have found and collected with Pontiac straight eights. I can't remember where they came from so I really don't know anything about them.

These are just to get your hopes up and your mind thinking. Hope it will inspire someone to do something else.

*This one is the engine from the "Pontiac Bonneville Special"(just google it to find out more) They say it has over 230 bhp.

*Then another with the Edmunds finned head and dual intake.

*To really mess you up I'll put one of a flathead straight 8(I don't think it's a poncho because of the radiator hose on top and plug placements) with a blower and what looks like two 4's on it.

 

The last one looks like the Dozier-Hagerty Chrysler eight in Hagerty's DeSoto Airflow. Motor went 250 in Dave Dozier's streamliner.

 

I had an abbreviated version of the Poncho straight 8 in my 41 Pontiac coupe...a 6 cylinder. I toyed with the idea of welding flanges to the stock exhaust manifold for dual exhaust but the Pontiac configuration isn't condusive to that approach. A home/shop fab'd header/intake system is about the only way to go unless you were to open up the ports in the block and stock manifolds. I'd make up a 3-5" spacer to go between the Pontiac 2 barrel carb and the manifold and a swap to a bigger, newer Rochester carb or maybe even build an adapter/spacer to allow use of a Holley two barrel carb. I agree with milling the head and/or block to gain compression.
Hog out the exhaust manifold a bit and use 2.5 inch exhaust pipe with a low restriction muffler or no muffler.
The petronix kit is a must.
These mods should get you an extra 10-15 HP. If that's not enough, I'd build custom intake/exhaust systems and have the stock cam reground.
Leaving the engine bone-stock and going with a supercharger/turbocharger and using electronic port-injection makes more sense to me tho. Gets your power in the low RPM range. These engines dont' like RPMs at all. The 3 [or 4?] main bearings let that looong crankshaft "whip" at anything over about 4000 rpms.
When I was a kid, we had straight-8 Ponchos. My mom was passing a slow truck on a hill with our black 50 Pontiac. It kicked down into passing gear [3rd gear in the hydro] and just as we were clearing the front of that truck, the bottom end let loose in the old Pontiac engine.....there was total devistation with oil and coolant falling on the ground.
I've had several straight-8 ponchos and always wanted to tweak one...sounds like fun to me.
I talked to this guy at Americruise in Madison, Wisconsin one year who was driving a black 41 Pontiac coupe with the straight 8. He used a '54 block and built his own headers and intake [600 holley 4 barrel] with a petronix, a reground cam, milled head and he fab'd up an adapter to bolt a muncie 4 speed to it all. It wasn't blindingly fast but made for a fairly peppy ride.
Personally? I'd go with a 60 and earlier Pontiac V/8 engine and a 55-56 slant-pan hydro tranny. The 55-58 cars used the same motor mount configuration as the straight 8/6 Pontiac engines. Not sure about the spacing between front and back motor mounts but if you can re-use the rear motor mounts, you can fab up a bracket to re-mount the front mount. This should allow you to keep your stock drivshaft. You'd need to relocate the battery but you'd need to switch to 12 volts anyway.

 

Hello
Here are some pics of my 1950's lakester I am getting back together with the straight Buick 8 turbo set up, which is all fabricated so you could do the same set up on any straight 8 like a Pontiac.

Yes the Easter Egg paint job will be gone soon, the car will be in front of the Suede Palace at the Grand National Roadster show this year.

There are also pics of the duel carb non blown set up.

If you are going to put a lot of boost on it you need to O ring the block. I am going to do that this week for sure. This engine did fine at 174 mph, run after run, but with more boost it blew the head gasket at 197mph.

For fun, anyone know what the close up picture is, the shiny disc? I didn't until a while back.

Hope these pics are helpful.
Take Care
Wil
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Right on, sign me up for a Pontiac 8 finned aluminum head if it's under $1,000.00

 

I have been toying with bringing my 1950 Strait 8 Poncho a little more forward with the times. What I have thought of is a 3 carb intake with 3 1bbls on it (thinking VW Solexes for simplicity and parts availability or get really crazy with multiple one barrele throttle bodys ) and home brewed Dual outlet mid length header, the hardest part will be having the flanges made as it looks to me that they are held down with the same bolts/studs. Thinking dual 1 7/8"-2" exhausts exiting out a set of "lakester" side pipes. Planning on swaping out the 3 on the tree for a T5 as well, should make for an interesting ride and quite a conversation piece at car shows. Oh yea, shes a 4 door too and a trunk you could park a toyota in

 

Dohc.

 

There was a Bonneville raciong car in the early '50s that used a Pontiac straight eight, A drawing of it was published in a copy of Hot Rod Magazine. For years when I worked at OLD CARS WEEKLY I kept that drawing by my desk, but I lost track of it after I left there.

There was also a famous MOTOR TREND road test in which they tested four cars including a '54 Pontiac, then hooked a trailer to each car. When pulling the trailer the Pontiac 8 outperformed the V-8s.

I have owned two '53 Pontiac 8s and a '48 Streamliner 8. I also have a '52 Pontiac 8 and tranny out of the car and a '36 Pontiac flathead six and a spare motor for it.

Gunner

 

hi i would be interested in an intake and a finned flathead also some exhaust header weld up flanges i have a 4.1 straight eight

the1thrill

 

Did anyone find that secret hoard of Pontiac straight 8 parts? If anyone has any pictures of their upgrades on their Pontiac straight 8 it would be great if you could post them.

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If it were me I'd save my money for a V8 swap. You'd just be wasting money trying to perk up a flathead straight 8. By the time your finished you could drop a V8 in it and spend less money. Not what you want to hear but it is what it is.

 

I understand the old flathead will never be fast. But I believe I can get more out of her and still keep a piece of American iron alive. Not to mention look cool doing it.

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Garage, these post's about hopping up old flathead straight sixes and eights continue to amaze me. Those cars couldn't get out of their own way the day they were built. Now seventy years later people think they can wake up these boat anchors with some so called "Speed Equipment". If you could even find and then install a high compression head and dual carbs, I doubt you could even feel the difference, especially with an automatic transmission. Any Soccer Mom in a four cylinder Honda would blow the doors off you after you've wasted all kinds of money.
I know I can install a SBC junkyard 350/350 combination for less then you'd pay for these hop up gadgets. Like I posted previously save your money, do a V8 swap and you'll have an old car thats fun to drive. Only then will you be keeping an old piece of American Iron alive.

 

I think you're missing the point...of course it's a lot easier and less expensive to make more horsepower with a modern V8, but some people like to work with what they have just to see what they can do to improve it. Besides, it would be a boring world if everyone did the same thing.

 

I would rather see a hopped up old motor than another 350/350 combo.

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only thing what limits these engines is the crankshaft , it will twist and snap . because its so long if it had been designed like the mercedes motor with the PTO in the middle it would have been a contender . but for a nice cruiser they were perfect slow and smooth . as for change out only a Poncho can go in . no chebbys .

 

A poncho V8 would be great. The only reason I mentioned an SBC was its cheaper and easier to find. Its always easy to spend other peoples money.

 

I'm interested how far have you gotten on the straight 8 Pontiac stuff??

 

What he said^^^^^

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Has anyone used a different carb other than factory carb with success?

 

mill the head to give it some compression. the stick version was 118 hp with 6.8 to 1 cr the auto had 122 runing 7.7 to 1. you could probably pick up 5 more hp running 8.5 to 1. Take .060 off the head, crank in a bit more initial timing, it'll feel like a bullet..........

 

Good god this is 7 years old!