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