Does anyone know how much power you can get out of a 250 sohc 6? I bought a 68 firebird with one in it and people are telling me that I can get alot of power out of it. I want to build a v-8 and put in it. Any thoughts?

[This message was edited by steve68bird on November 05, 2002 at 10:13 PM.]

Does anyone know how much power you can get out of a 250 sohc 6? I bought a 68 firebird with one in it and people are telling me that I can get alot of power out of it. I want to build a v-8 and put in it. Any thoughts?

[This message was edited by steve68bird on November 05, 2002 at 10:13 PM.]

Just guessing here, but I would think that 300hp would'nt be unreasonable. They will rev! I'm thinking that some cylinder head port work, custom reground cam (no new ones that I'm aware of), exhaust header (again, a custom piece) and maybe play around with the intake. I have a couple of these engines, in pieces on the shelf. I'm going to build one for a hot rod sometime in the future. They are light too, I think they weigh around 400# complete. They were really ahead of their time. They sound great at full wail!

It's not NASA you dolt! It's NACA!

The SOHC six is a neat engine. But if you really want power tuck that six under your workbench and build a V8. Even a mild 350 engine will out-power a built-up six. Good luck! [img]/infopop/emoticons/icon_wink.gif[/img]

Let's go racing!
www.outlawpontiacs.com/members/B-Man2.php
www.outlawpontiacs.com/members/B-Man.php

I was also told that the engines have great value, is this true? This is my first musclecar so I want to get it right. Thanks!

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by steve68bird:
I was also told that the engines have great value, is this true? <HR></BLOCKQUOTE>

It depends. If it is a 4-barrel engine it may be worth some decent money to a collector. Otherwise they really aren't worth all that much, not many folks want them I'm sorry to say. [img]/infopop/emoticons/icon_frown.gif[/img]

Let's go racing!
www.outlawpontiacs.com/members/B-Man2.php
www.outlawpontiacs.com/members/B-Man.php

Well if I had the money I'd get it, but if I had the money I'd also get a 400 and a supercharger etc...

I've always liked the idea of a 1968 Firebird Sprint with the 250HO or whatever. It isn't always about power, sometimes just fun ;-)

Tyler

I still have the Hot Rod article from 69 with a SOHC from the factory back room with 4 Valves per cylinder.

The only concern would be the belt. They also had cam wear problems, I guess from soft cores.

I built my share of Chevy 250's, and hammered a few SBC's on the street. Back in the day.
4 spd/Vertigate with 4:88's in a Camaro. Block to block it was a killer. Pissed off a few people when I opened the hood. LOL. Even had the single bbl....... off a marine 292. [img]/infopop/emoticons/icon_wink.gif[/img]
194 head with oversize valves and ported. etc. A lot of tricks to do to them
But with the OHC imports these SOHC Pontiacs are like Elephants heading the the Elephant graveyard.

If you check some of the early mags....the OHC Firebirds turned better times then the 400's off the showroom floor....back in the day.
I'd like to see an 11 second OHC Pontiac in a street car. Then add the juice. [img]/infopop/emoticons/icon_wink.gif[/img] WOW.

We will match or beat anyone's "Current" catolog price on any Automotive related part. Give us a call. We build and learn from em all, but We "LOVE" Pontiacs!!!
http://PontiacDude.cc

keep the 6.

Graft an even-fire 6 HEI to that points distributor cup. 4-bolts will hold it on.

see your other thread, my other post.

"11.00/123MPH/1.50 60foot/29.5"/4.10:1/10"/472 #48/Flat HYD/DualQuad/Wenzler/3250Lbs
12.00/112MPH/1.61 60foot/26"/3.31:1/10"/472 #48/FlatHYD/Q-Jet/Torker/3650Lbs"

Steve
If you want more information on these engines and the OHC cars, go to:

http://pub83.ezboard.com/bsohcsix

The one barrel engines are not really worth much but the Sprint four barrel version is pretty rare.

As far as power output there are a few people that have really made some progress (over 400 hp!). You can find them on the OHC board. Triple Webers, centrifugal blowers, EFI, etc. Not cheap, but great fun.

BTW Pontiac never referred to them as SOHC, only OHC.

Chris

If you are really in to these, obtain a 1-barrel engine (expensive they aren't, we gave ours away to get rid of it!), and order the 3x2 manifold from Clifford (part number 46-3040) for Weber 2-barrel sidedraft carburetors (no, we don't have any for sale).

I would agree with the Dude that they are pretty neat. They were advertised at the time to compete with Jaguar. Well, they didn't. Too bad GM didn't do a little better job with this project. A chain and gears would have been a good starting place, rather than the belt. Also the 3x2 sidedrafts (when all performance imports came that way) might have significantly boosted sales. I tested one (4-barrel version) in 1967 (I think), and was quite disappointed.

Jon.

Good carburetion is fuelish hot air.

Thanks everyone for your comments and suggestions. It's good to have people to turn to with actual Pontiac experience. I hope I haven't bored anyone with my questions. I can assure you that I will post again as I actually figure out what I am going to do. Once again, thanks!

i have really been wanting to play with one, i think a 4 barrel intake, with some sort of EFI, like accel would be cool, with a large turbocharger, and see what kinda power can be made with it, then head out and see what you can do with them supra boys with 30+ year old technology with a litte new added in [img]/infopop/emoticons/icon_biggrin.gif[/img]

Steve, My 68 Bird is a Sprint, had 250HO With 4V carb, dual exh, etc. It's a strong motor but I took it out(saved it) and put in a 455, worked up and dyno tested. It all depends what you are looking for out of a car, how much performance, and what kind of money you want to put into car/motor. A strong 6 cyl OHC will turn some heads. The correct motor mounts are only being made by 1 person and are a little on the expensive side as mounts go. Mounts in regular aftermarket books are not correct. Also, see what internal parts are avalilable for your motor,and their prices before you decide on the 6 cyl rebuild. Build the car the way that YOU want it, it's your car and $$$$.

Carbking (Jon)
Why do you think that the engine needed a chain? The belt works great, allows for very high revs, is very dependable and quiet to boot!

The main issue for really high performance applications is the lack of available cams and compensating for the added lift and duration when you do go that route. I would agree that starting with a one barrel motor is the way to go. The three weber intake and carbs are really expensive, and difficult to set up and run properly. However, it is pretty awesome once you sort it out. For some inspiration, check out these sites:

Three webers : http://jetson63.tripod.com/hotohc67f...print/id8.html

Blower motor:
http://sprint69.tripod.com/sprint69s...bird/id16.html

Boat motor from hell:
http://www.geocities.com/ohcjhatch/PontiacOHC6

If you want to, you can really make some power, even with the stock motor. Half Inch Stud gave me some great instructions on how to graft an HEI to work in place of the points distributor, and I believe him when he says it makes a big difference. I will probably go that route once I get some time to mess with the Sprint cars.

78Lemans
If you are serious about wanting to build one up, let me know. I am in Arlington and will gladly set you up with some raw materials to work with.

Chris

I think a Driver-side-mounted (on manifold) Roots blower would be excellent.

too bad the EXH ports are in the way..if not the Blower would mount flat against the block.

66Sprint...when the motor&car are just sitting(now) is the best time to do the distributor upgrade.

"11.00/123MPH/1.50 60foot/29.5"/4.10:1/10"/472 #48/Flat HYD/DualQuad/Wenzler/3250Lbs
12.00/112MPH/1.61 60foot/26"/3.31:1/10"/472 #48/FlatHYD/Q-Jet/Torker/3650Lbs
12.70/103MPH/1.71 60foot/28"/4.10:1/12"/472 #48/FlatHYD/Q-Jet/Torker/3950Lbs"

66sprint - hearsay! (I already admitted being disappointed in the test drive so have never personally owned one).

(A) supposedly belts were good for 60-80K (constrast with a Jaguar I had that had well over 200K on the original chain).

(B) special tool (which at the time was ridiculously expensive) needed to change the belt.

If both of the above turn out to be incorrect (as I mentioned, hearsay); then I withdraw my objections to the belt; although the music of the chain to the OHC crowd (at that time) was like the music of a tripower at WOT to a GTO nut.

Jon.

Good carburetion is fuelish hot air.

Nice to see a OHC posting! I have recently rebuilt my Sprint motor for my 67 Firebird Convertible. Parts can be difficult to locate, and are a little on the expensive side. But the "wow" factor and performance is impressive for a Inline 6! E-mail me if you need parts sources, specs, advise, etc... : [img]/infopop/emoticons/icon_biggrin.gif[/img]

Now that's a purty motor, even if it's missing a couple of cylinders! [img]/infopop/emoticons/icon_wink.gif[/img]

http://kurtsplates.homestead.com/files/gsgoat.jpg

Hey, if you really don't want the 'bird with the OHC-6 in it, e-mail me. [img]/infopop/emoticons/icon_biggrin.gif[/img]

http://kurtspontiac.homestead.com/files/bbaker.jpg

I want the Bird, I just don't know what I want to put in it! [img]/infopop/emoticons/icon_confused.gif[/img]

As has been said, it depends on what you want from the car. If power is your thing, sideline the 6 and build a 400 or larger engine. You can get good power out of those motors, but it will cost a lot more than a typical V8 buildup and won't make the same power for the same money spent.

Now, if you want to build it just because you like the idea of the OHC-6 and want to do something different, go for it.

Back in about '89 a friend of mine had a triple black '68 Sprint convertible. Man, that was a neat car. 4bbl "Sprint" 6, 3-speed on the floor (with console), and 3.55 gears. It wasn't fast, but it was wayyyy cool. If I could ever find a car like that again I'd do like another friend of mine and buildup that motor with a Vortech on it and put a 5-speed behind it.

It's your car, do what will make you happiest.

http://www.willbaker.com/misc/BLUBLUR2.jpg

I've almost decided to go with a 455 if I can find one. How much will it cost to build one for good street performance? I've seen some on the net ready to drop in for around $5500-7000, that is more than I want to spend right now. I still have to get tranny, radiator, etc. I would like to get it running and build it up as I go. Any suggestions?

If you can find a 455 and if you do the work yourself, you can put together a real nice street/strip 455 for around $3K. The more stock parts you retain, the less the total expenditure.

http://www.willbaker.com/misc/BLUBLUR2.jpg

sprintbird;
your picture reminds me of the complete 68Sprint I shipped to Ontario Canada. HEI, nearly new Y-Pipe, and spare 69-4bbl MT cam. Never heard back from the fella. [img]/infopop/emoticons/icon_rolleyes.gif[/img]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by carbking:
66sprint - hearsay! (I already admitted being disappointed in the test drive so have never personally owned one).

(A) supposedly belts were good for 60-80K (constrast with a Jaguar I had that had well over 200K on the original chain).

(B) special tool (which at the time was ridiculously expensive) needed to change the belt.

If both of the above turn out to be incorrect (as I mentioned, hearsay); then I withdraw my objections to the belt; although the music of the chain to the OHC crowd (at that time) was like the music of a tripower at WOT to a GTO nut.

Jon.

Good carburetion is fuelish hot air.<HR></BLOCKQUOTE>
Sorry to dredge this topic back up, but I came across it searching for something else and HAD to respond to Jon.

Jon, the belt tool is not necessary (was only for setting the tension). Also, the recommended change for MODERN belts is 60-80K. I don't recall any replacement recommendation for the OHC6 Pontiac.

However, I've NEVER seen a belt fail in these engines with 200,000 miles or MORE, with one exception. That one was oil soaked from a failed front seal, and the belt was original. This was in the mid-90's. Car and belt were almost 30 years old, and car sat a couple of years. Teeth stripped at crank from the oil damage when attempting a restart.

I can R&R the cam cover (by slipping the belt off and back on) in ten minutes. If I miss the marks, I can slip the belt on and off again in just a minute with only a standard flat screwdriver. Ask Ed Hibrass Harley - he watched me do it once.

To change the belt requires pulling the dampner, but again, I've never had to do that for the belt only. I don't even need to remove the belt for a water pump swap.

These engines, while primitive by today's engineering standards, are still attention-getters at car shows. Remember too that Pontiac and US Royal Rubber company invented/engineered the belt, which has become the industry standard. Fixed-position hydraulic lash adjusters (rather than the complex maintenance needed for such cars as your beloved Jaguars) were another interesting feature in the day. Among other things, there's plenty to love about this engine!

The 230 inch version is probably the only bone-stock Pontiac production engine that freely revved to 7,500 RPM or more...

Glenn Uettwiller http://home.earthlink.net/~birdman8/index.html

A friend is someone who knows the song in your heart and sings it back to you when you have forgotten how it goes. --- unknown

Glenn, I had one in a '67 LeMans and duplicated all the things you mentioned; pulling the belt on and off, etc. Only complaint I had about the power was that it would come on after about 3000 RPM; a little difficult getting a Lemans moving from a stop light. Put in a 5 speed tranny with a 3.5 first gear coupled with the original 3.90 rear axle and I would tear up the asphalt. Tach red line was 6500. Still have the tach, going to recalibrate it and put it into my GTO.

George

I have the manifolds, carb, and air cleaner for the 4 barrel conversion if you want to do that.

69 GTO RAIII 4SPD BURGUNDY
69 GTO JUDGE RAIV AUTO BLACK
03 HD XL1200S SPORT BLACK

Glenn - all objections withdrawn (except the disappointment in the test drive). Please remember I looked at one of these when it was new, and the information about the belt was given to me by the dealer at that time. Due to those disappointments (belt and test), I have never owned one of the cars.

Jon.

Good carburetion is fuelish hot air.

I've spoken to Fred Simmonds, who owns a 67 Tempest four-door, with four-speed, benchseat, A/C and Sprint engine. I'm pretty sure he owned a new 67 LeMans Sprint, that with nothing more than a rear gear change was turning 13.99s back in the day.

When he lived near here in Central Florida with the sedan, he installed a 3.50 first gear Saginaw, which with the 3.23 axle (A/C ratio w/4-speed), he said made a marked difference in getting the car rolling.

PS the critical "Sprint" component is the cylinder head, which gives the 10.5:1 compression ratio. Thanks anyway, JK, I'm overloaded with four-barrel manifolds...

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> George wrote: Only complaint I had about the power was that it would come on after about 3000 RPM; a little difficult getting a Lemans moving from a stop light. <HR></BLOCKQUOTE>
Sounds no different than my buddy's 1969 Z28 with 3.31:1 axle! He ordered it new that way, still has it, mostly original.

Glenn Uettwiller http://home.earthlink.net/~birdman8/index.html

A friend is someone who knows the song in your heart and sings it back to you when you have forgotten how it goes. --- unknown

I feel your pain...

My 1967 Tempest Ragtop came with the 6 and a 2 speed auto. It was tired @ 80,000+ miles and I let my mechanic talk me into rebuilding it stock. Oddball hard to find parts. I bought a factory 4BBl manifold, but never located the correct cam and carb to make it really wail.

After adding electronic ignition, dualing out the exhaust, a rebuilt engine & trans, new tires, brakes, shocks, springs, gas tank, radiator... should I go on?

It will move out OK, even bury the speedometer on a long enough straightaway, won't overheat like an old Goat in heavy traffic, but NO WAMPAAHH!!
You hammer down on it and increase speed about as fast as a bread truck!

Long story short, today I'm waiting for somebody to total a Holden GTO, so I can buy the LS1 powertrain to switch out. (Or maybe even an LS2!!) Somebody else posted the truth

"Even a mild 350 will smoke your 'Built-up OHC-6'"

So, if you want your ride to have some balls, don't do as I did, do as I say, because today I just slap my forehead and proclaim that for the same or close money...

"I could of had a V-8!!"

Sell your six to a historian, if you can find one, I'll be happy to sell someone mine!!

I don't want my ride to be too nose heavy, but there is no substitute for cubic inches, and EFI is where it's at in 2004.

I'll be back...

Are you still running the 2 speed? What axle ratio?

It's in the combo, right? I had a 2 speed once, adding a third gear was a hug wake up!

Ol Blue - we have carbs.

Jon.

Good carburetion is fuelish hot air.

Ol' Blue, you needed some compression. THAT, my friend is what wakes up these engines. You ran the four-barrel setup on the 9:1 head? No wonder it's dead.

I ran about 11.5:1 (the 67 Sprint head on a bored 250, ports cleaned up a little) with all other stock components. Car came to life, and smoked the big rear tires as it whomped second gear (stock TH350!) at about 50 mph, with a lame 3.23 rear.

Your combo is just not right.

Glenn Uettwiller http://home.earthlink.net/~birdman8/index.html

A friend is someone who knows the song in your heart and sings it back to you when you have forgotten how it goes. --- unknown

Nope, didn't switch heads, but I know what you mean.

I bought a 4 BBl intake/exhaust manifold, just never used it. All I did was have mine rebuilt, with a new stock grind cam.

I hsd a '65 GTO when I was a kid to compare to, so, It'll never be quick enough without a V-8. My 6 will squeal a tire too, but I would need to run 4:11 or 4:55 gears to launch respectably with this six.

I like Highway cruisin' too.

I'll be back...

Carbking,

Want to buy my 4 bbl manifold?

I'll be back...

TD,

Yeah, which 3 speed did you hook to yours? How much did the changeover cost? I don't know what my diff. ratio is. Probably stock, no A/C, or power anything else, just a bench seat ragtop, when I bought her.

I used a TH350 since it was a direct swap.

It cost me something like $150. But I got the trans core for free and a buddy to rebuild it.

This was 10 years back.

You need a steeper gear to really use the power, Figure out what you have first.