Hey guys, I haven't been on here in forever and thought I would pose a question. What would you think of a 3rd gen Firebird with a 1969 250ci OHC straight 6 in it. It would actually be a stroked 270ci straight 6 with clifford aluminum intake manifold, sprint exhaust manifolds with a single 60-1 (or equivalent) turbocharger on it running a Ford DIS-6 ignition and megasquirt efi. I had deisgned this engine for my 69' Tempest (GTO look alike for those who don't know lol) project but opted for a LS1 twin turbo build instead. This project is nearing it's end and I can't bring myself to part with the original motor from this car. Mainly because it';s so neat, it's an original overhead cam design from 1969 and it's belt driven!!!! No timing chain or gear drive, a belt drive. I've been debating what I could use this for and seeing as how there are plenty of 3rd gen birds' around here, maybe dropping it in with a 200R4 tranny. Since I've built a couple of these 3rd gen's from the ground up already, it would be a good project to jump into. Any opinions?

 

WHY???

 

Why not? You can make well over 500hp on stock block and crank with them, more with the stroker kit. Comes with skirted block from the factory, 4 bolt mains and provisions for 2 side bolts to make it 6 bolt mains, it's been tested by pontiac using the GMC 177 blower back in the day and they couldn't blow it lol. It's a STRONG motor, and very ahead of it's time for the day. Plus it's sitting on my engine stand and I have nothing to do with it

 

Hood clearence!

Look in a recent issue of Super Chevy, there is a 3rd gen bonneville car with a straight six. It has one funky looking hood to clear.

 

I'll have to check that out. A RAII hood should clear it though without a problem. The motor isn't THAT tall. The Pontiac V8's take about the same amount of room height wise. I still think it'd be neat having a turbo'd Pontiac OHC6 with a vanity plate that reads 2JZ WHAT haha

 

That quote by Whitey Almighty is great... That a member of this board?

I've driven a truck with a 250 I6, it didn't seem to be a great motor by any stretch of the phrase. Maybe this was a different motor, since you're saying it was an OHC? So, no pushrods ? This would give a higher RPM range right? What's the bore/stroke on it? Less than favorable?
With a turbo and a gigantic intake and a solid bottom end, I guess it could work. But only 270ish cubes means you'll have to rev it up a lot to get your power out of it. Not really what i'd want in a 3rd gen. Maybe a Nova, or something really light?

 

250 is a ohv engine. It would fit under a stock hood with no problems. QA 292 would have hood clearance problems.

 

No, he's a member from another board I'm on, I thought it was great too. There's another one "people are like slinkies, most of the time they are useless but you always get enjoyment pushing them down a flight of stairs". lol. The motor from the factory spins around 6500-6700ish depending on which year Sprint motor you had. Mine spins around 6K right now but with a custom grind cam, new valve springs and followers it'll sustain 7K no problem and make power down low. One guy has already made over 400hp with one on a stock Sprint engine just running a powerdyne (blah) blower at 9psi. Figure custom grind cam, EFI and DIS, 12-15psi from a more efficient blower setup, and your talking well over 500hp. The stroker kit uses a 3.75" stroke, 3.875 is the standard bore size and of course you can go larger pistons. And yes no pushrods, it's a 4.1 liter in 250ci size, so it's around 4.7-4.8 in stroker form. It makes alot of low end power too, power band (depending on application) starts around 2500-3000. Here's a pic of the blown one





Ya the 250 OHV is about the same size as my 250 OHC, so depending on how I run my piping it should fit fine.

 

oh right, you said '69 Pontiac, so the pontiac 250 I6 is OHC, I drove a chev 250 I6 OHV - obviously nothing special.

Well you'd certainly be unique I guess, I don't know squat about that engine that's for sure. "image hosted by tripod" is all we've got there..

You'll have to post a picture of this weirdo motor as well.

 

----------

 

I think it would be great! Depending on which 3rd gen you pick up, make your tranny decision then. If you pick up a standard shift use a T56 (you'll need an adapter); if you get the more common auto car, go with a 2004R (bowtie overdrives has some good GN spec units) and a spohn crossmember to accomodate your torque arm mount or use a built 700R4 with an adapter plate!

Either way, it will be awesome!

 

That's purty

 

Ya I have yet to see a way to make the T56 work (still searching). Was also considering a Muncie 4-spd if it was a stick car. If it's auto it would def be a 2004R. I just can't seem to want to part with the motor because it's so neat lol. Oh well when the 69' is done I'll start this project haha

 

While we are on the 250 I6 thing, I am guessing most of you have never seen the factory Multipoint injected 250s.

 

Heck ya man those things were neat, too bad it wouldn't work on my motor. I thought about doing a hybrid thing with that EFI system but too much of a PITA. Plus really hard to find lol

 

The motor may not be much taller, but it is longer, which will cause clearence problems at the fron of the motor, where the hood slopes down so much.

It would be cool though, I have a sprint 67 firebird, and looked at building a turbo motor for it.

 

Where did that chevy fi 250 come from? What vehicle had that in it? Just curious 'cause I've never seen one except in these pictures...

I have heard (but not seen in person) that if you use the thick auto trans adapter from Chevy transmission to Buick/Olds/Pontiac engine (the 3/8" thick plate) that you can run the T56 behind that. You need a 3/8" thick spacer for the flywheel with longer bolts and a spacer for the pilot bearing.

I talked to a guy in NW Ohio who had done this with an NVG3500 to put behind his Olds engine. I didn't get under the truck to see it. It was in a 91-ish 1/2 ton Chevy.

 

The problem is the OHC-6 has a weird starter placement, and for the most part you have to use a OHC-6 specific bellhousing. Some V8 housings work but not all. That FI motor was in the Omega, you never saw it in the states as it was mostly in brazil and overseas. They made it until the mid 90's

 

Does the starter bolt to the engine or the bellhousing? I'm asking because I saw an article where a Northstar V8 was being bolted to a V6 700R4, both with GM Metric transmission bolt pattern, but they didn't mate perfectly due to starter location. A little grinding and welding on the transmission housing (heck, it IS aluminum) and it was good to go. Looked great in Hot Rod.

I'm just saying; as trick as your engine looks now, I can't imagine that a little tranny mod would scare you now!

Good luck!

 

LOL ya the starter bolts to the engine but kind of offset compared to your typical sbc and such. On the auto's you only have "half" a bellhousing so it's not a big deal, on the T56 and such the bellhousing goes all the way around and there has to be a opening for the starter. I'm sure it wouldn't be a HUGE deal, just need to cut up and reweld a bellhousing but just kind of hesitant doing it and risking it breaking apart on me haha. I'll probably look more into it when I'm ready for the swap

 

Yes the 4.1 was made with a single barrel TBI unit that housed a 125 lb/hr injector as well as the MPFI setup pictured. A quick seach on Youtube proves a responsive, well mannered 4.1. 5,500 rpm redline, WOW.

http://youtube.com/watch?v=CavJIr_RYMw

http://www.youtube.com/watch?v=CR3-oh5qfgA

http://www.youtube.com/watch?v=ytUv4Vn9afM

Apparently they came backed to a 4L30E as well. That had to be a good running combination.

http://youtube.com/watch?v=mcKPYpWg01c

Here is what I find crazy, check out where the rev limiter is, like 5,800 rpm

http://youtube.com/watch?v=2hftUW98ceg

 

What's even funnier is the Sprint motors from 67-69 had a redline of 6500rpm!! That was CRAZY back in the 60's lol