I had this crazy idea a while ago. I want to sometime in the future, build a performance 300 I6 and turbo charge it. There is one bump (or maybe 1000ft cliff) in my plan. I want to put a DOHC 4v per cylinder, cylinder head on. Obviously no one makes anything like it, seeing as how I am yet to find a single performance head for an I6. Is there any possible way that this goal could be reached? Are there any companies anyone knows of off hand that could make such a product? Could it even work? I dont own an I6 engine and never have, but I would be very interested in building such a beast after I graduate, if it were possible of course.

 

Anything is possible if your pockets are deep enough, but I don't know why you would want to do that. This is one case where I will say that you are better off starting with something else. 4V heads are not as good for low end torque as 2V heads and you'll have to spin it until it turns a pleasant shade of blue to make a 4V head worthwhile. That means better parts in the bottom end and more money. It wouldn't surprise me if you were into it $15k before it was all said and done.

 

Yeah, just gather your own team of engineers, a foundry and a machine shop and you could have it done! But if I were you, I would wait until one of these decades when the guys at Ford Six Perforance Parts finish developing their performance aluminum 4.9L head. Wasn't that thing supposed to be done a couple years ago? oh well, my six only has 235,000 miles on it.

 

Well like I said I dont know much about the 300 but I do know that these engines crap out at about 4000rpm. Wouldn't more flow from the valves and forced induction help with high end hp which I know these engines lack. A guy from the general engine building forum told me he knew about some ford australia inline six engines that were DOHC turbo charged. I looked it up and found out that these engines make a very decent amount of power in stock form. The displacement of the engine (Barra 270T they call it) is 4.0L and I believe it has aluminum rods and pistons. Im sure if the 300 had a lighter rotating assembly, the higher RPMs shouldnt be as bad for it. If the 4.0 makes (according to wikipedia) 362hp at 5250 rpm, the 4.9 could reach numbers similar to that. Im not planning on starting this project until after I graduate and Im not planning on putting it together right away. I would talk to some people with more knowledge than I possess and find a general consensis to what would be the best and most reliable way to put this engine together. I plan on taking an engine building class at wyotech and that would help out alot. This is still more of an idea than a set in stone plan right now.

 

A 24v not being good for low end torque??? My "other" I6's stock torque is 460!! But I'm cheating there with it being a CTD.

Realisticly, a DOHC 24v 300 would need a new block design as well as head to have a chance of being reliable and not a novelty.

What "might" be possible is crossflow OHV 24v with the existing block design. I'd guess the development costs would exceed 50k. Good low end torque can still achived with a good match of c/r and cam profile.

Personally, I'll wait for the ClassicInlines (formerly Ford Six Performance) Aluminium head that is in prototype stage. Their small six head is about to go into full production with new intakes being developed as well.

Just my 2 cents

 

That is true, but it's also by design. Traditional hotrodding tricks work very well on the 300. Most traditional truck engines don't do much above 4000 rpm because that isn't where they need to perform.

Yes, but you can get there with existing parts. No need to reinvent the wheel. A 300 with production based top end components can be built to make power at rpm levels that are beyond the capabilities of the stock bottom end.

That engine was probably designed from the ground up to work that way. The 300 wasn't and it will cost dearly to make it do it.

The problem isn't so much the weight. The parts aren't any heavier than those you'd find in any comparably sized cylinder. The problem is that the stroke is long and the rod angles suck dog *****.

The 300 can approach, and even surpass, those numbers with well chosen and prepared stock parts. You'd probably be looking at a peak rpm of around 5500 and peak torque around 400 ft-lbs between 3500 and 4000 rpm. It would basically be just like Col Flashman's build with a stouter cam in it.

SR, the CTD is a totally different animal because it has twice the compression, a completely different fuel delivery strategy and some funny hair drier thing hanging off the side of it. Those things combine to negate much of the need to swirl and tumble the incoming mixture at low engine speeds. 4 valve heads tend not to do either very well because the mixture motion generated by one valve is offset by an equal and opposite attempt to generate motion by the other valve. Not to mention that 4 valve heads typically have lousy quench areas in the chamber because there isn't anywhere to put one.

 

So this performance six head you guys are talking about. Im guessing its a 16v head. Does anyone know much about the australian sixes like the Barra 270T? Im curious what the size difference on the block would be. If the LxWxH is the same, could that be used as a base to just machine an identical head that could bolt to the 300? I really am just in fantasy land right now I really honestly have no idea what Im talking about, Im just asking the questions. lol. I kinda wish I had had one of these engines around when I was younger. Growing up around chevelles and mustangs, I could take a carbed small block V8 apart and put it back together no problem. Ive never even seen a 300 broken down. There are alot of 300s in junk trucks behind the shop at work that would be scraped if the trucks didnt have some good parts on them that my boss wants to keep. I never have tried or really have time to look at them and study them to see what they are like to work on. So back to my point, I understand making one is out of the question and I probably wont be able to use one of those aussie six heads cause I doubt it would be big enough. I guess I will have to wait and see what other companies come out with. Maybe there will be a good performance head out by the time I get done at wyotech. I just wish I could do a DOHC just for the fact that it would be the only one like it around and well it would just be insanly cool.

 

Silver streak,

you musta posted your second reply while I was typing. Thanks for the extra knowledge. I didnt realize that about the 4v heads. Since it seems almost impossible to do, I probably wont try with the 4v. If a good performance head does come out, I could probably settle for that. It doest put my imagination down tho but practicality and reliability is more important than it being cool. I wouldnt want to spend alot of money on a project that "sorta" works or that will break down the road.
Im interested in hearing more about that guys buildup you were talking about. Who is col flashman and do you have a link to any info about his buildup. If he can make a high perf. 300 with traditional parts, maybe I could too and still be happy with it.

The rest of my idea was to find a 96 f150 st cab short bed 2wd and make a lightning clone out of it and slap in the 300. I could just see peoples faces when they see what they think is a lightning and look under to hood to find a big ol 300 and a turbo charger staring back at them.

 

I did say I was cheating. Mines very mildly mod'd and delivering flywheel torque somewhere north of 600. Need to put it on a dyno to get real numbers though.

I see your point about quench though. In all honesty, a 24v 300 would be chasing top end power and not low end torque anyway. And I don't see anyone willing to shellout the research funds to make it happen.

 

I have had this same Idea or dream for about 4 years now. I have a 91 f150 with the 300 I6, and just love it. I am thinking just keeping it simple though and just P&P the head, maybe larger valves, but probably not, porting the hell out of the intake and putting a turbo on it. I am not looking for huge amounts of power, or performance, 275-300 hp, at most. something you should consider about the 24 valve idea is. This engine is not made to rev high and have high end power. With a 4" stroke it will never be a high rever. Also the intake manifold design, with the really long runner, create low end torque and is less than ideal for high reving. If you are looking for a 7000 rpm engine, I don't think you will get it out of a 300. May be you could find an old 240 block that has a 3.18" stroke, If they will be interchangeable, It could be a VERY high reving motor!

 

I have had this same Idea or dream for about 4 years now. I have a 91 f150 with the 300 I6, and just love it. I am planning on just keeping my build simple though. Just P&P the head, maybe larger valves, but probably not, porting the hell out of the intake and putting a turbo on it. I am not looking for huge amounts of power, or performance, 275-300 hp, at most. something you should consider about the 24 valve idea is. This engine is not made to rev high and have high end power. With a 4" stroke it will never be a high rever. Also the intake manifold design, with the really long runner, create low end torque and is less than ideal for high reving. If you are looking for a 7000 rpm engine, I don't think you will get it out of a 300. May be you could find an old 240 block that has a 3.18" stroke, If they will be interchangeable, It could be a VERY high reving motor!

 

[quote=mrl390;5071842] I really am just in fantasy land right now I really honestly have no idea what Im talking about,...Agreed.

Put a huge sum of money on the line, do the research and development and post the results here when it is accomplished.

 

forget that and private import a barra. at the last summernats event (33) a destroked turbo barra made 2202 HP! yes 2200hp in a daily driver. you will be wasting your time trying to convert a old 300ci engine when ford australia has done all the hard work for you and its a proven package... alternative fuel is not a problem: many turbo engines have built using propane only as fuel and getting respectible MPG. no its not like japanese engine
https://www.whichcar.com.au/events/s...-summernats-33

 

starting a DOHC 300 sounds like an unfinished project waiting to happen. Barra the world

 

https://www.fordsix.com/attachments/...058-jpeg.9040/
And
https://www.fordsix.com/attachments/...2b3-jpeg.9041/