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What would it take to make 600hp from a Cleveland? Could it be done with the Iron 4V heads? I was looking at the 408C build Dan posted and it got 520hp with the CHI heads. JGM claimed 704 with a +.700 lift cam, Trick Flow heads, and 13.0:1 compression. I don't own the book, so I haven't seen the 600hp graph they claimed.

There are lots of 400hp builds, but I would like to go significantly beyond that. On e85 if necessary, but pump gas preferred.
 

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A stroker kit, compression matched up with the right camshaft and decent heads. Running E85 allows you to run more compression compared to pump gas, and on average, for every point of compression higher than baseline, you will gain about 4+% in power. So a 12:1 compression engine will make about 12% more power than a 9:1 engine, all other things remaining equal.
 

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I haven't been watching flow specs of many Cleveland heads over the years, though I've gotten an idea of how the CHI heads flow.

So IMO, I think the key is having enough airflow in the heads and intake, to reach the power levels we hear about very rarely. The stock heads need a lot of work to kind of correct the massive port sizes, and exhaust flow angles. Most people aren't ready to do that, stuff which used to be trick and rare in 1980, now it's tough to find a shop that can do it.

The aftermarket Cleveland heads all seem to be aimed at mild performance, most flow well under 300cfm. I'd bet they are all very close to the level of the tons of common Windsor hear choices, which run about $1500.

So I think if a big number like 600hp NA is the goal, you won't get there with a 270cfm head. It probably will take a head that's over 300cfm, and that leaves a short list of heads. I know many push to 400cfm, but those are $4k heads etc.

I was hoping to find a CHI 3V head that flowed near 300cfm(@.550 or .600), for a NA 351 Clevor. They want you to buy the little 185cc version, yet they make a 208cc 3V head, and one a little bigger still. I like the CHI heads because you can get them with Windsor end bolt patterns. I'd mount stock Explorer 302 brackets and accessories to the, all common and easy to get parts, for a Windsor 302/351 block.

@damage, your plans will include bigger cubes I hope, so add the higher compression and custom cam. Use a big intake, and big headers etc, and maybe you will be close depending on the rpm's.

I suggest asking directly some of the old school Cleveland builders. There are some here who know how to cam them, most know the OEM heads well, and hopefully someone knows how some of the aftermarket heads work.
 

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@damage, your plans will include bigger cubes I hope, so add the higher compression and custom cam. Use a big intake, and big headers etc, and maybe you will be close depending on the rpm's.
Definitely more cubes. The block I have now is a low mileage 2-bolt. I have a torker intake now. But I'm pretty sure that's not enough for a mid 600hp motor.

E85 is easy to get as well as Sunoco fuel. But I would still like to stay under 12:1.

I'm not afraid to port the stock head. Unfortunately, in it's time the secrets were closely guarded. Sadly, now many of those guys are gone (at least around here) and so is their knowledge. :frown2:

I suggest asking directly some of the old school Cleveland builders. There are some here who know how to cam them, most know the OEM heads well, and hopefully someone knows how some of the aftermarket heads work.
I'm hoping some will find this post over time and chime in. I don't plan on starting anything until next year. I would like 600hp with the stock 4V quench head and an ok to drive on the street cam. I'm not talking about drive-able so much as a cam that isn't all on or all off and can handle power brakes. But maybe 500hp is that wall. And that's ok. But I wanted to know definitively.
 

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You will need a roller cam, and custom, made for all of the parts and the car.

I have a Torker intake also, new in the box. I bought it with plans for a 408 in about 1986, using a 400 block and 4V heads. That was old school back then, that and a 351W with a 400 crank which was easier.

The Torker isn't big enough for the cubes you'll need, and the rpm. Back then the Holley Dominator was the top intake, I don't know what is now.

Pick your cam designer, choose one that has done Cleveland cams. Let them guide the level of compression. I bet 12:1 is not high with E85 fuel, if you can run that all the time.

BTW, I still have several Cleveland parts, including my first car's engine block, a 2V from a 72 Gran Torino, and the 400 block I had Milodon mains installed on. It's a screw-in freeze plug block, now, I was aiming for a 70 Mustang with Boss 400 stripes. I was naive and thought that would be special, then I learned how much a car project from scratch would cost.

Build what you have, make it run great, and then you'll enjoy it more.
 

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I built a 351c with my pops just recently. 13:1 dome pistons with 4v open chamber heads with about 2k dollars of work done to the heads. Comp cams 304hr cam .612 lift if I recall, and an old school Torker intake on it. It makes a #### ton of power. My 393 stroked Windsor in my foxbody makes more torque, but the Cleveland in my 65 pickup is by far a better race engine. Before you get started on the fact that it has a torker intake on it. My dad ran an old school torker on his 289 back in the day, so he wanted to stick with what he’s always ran. Anyways... the Cleveland is a complete monster and can destroy most cars on the street.
 

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I built a 351c with my pops just recently. 13:1 dome pistons with 4v open chamber heads with about 2k dollars of work done to the heads. Comp cams 304hr cam .612 lift if I recall, and an old school Torker intake on it. It makes a #### ton of power. My 393 stroked Windsor in my foxbody makes more torque, but the Cleveland in my 65 pickup is by far a better race engine. Before you get started on the fact that it has a torker intake on it. My dad ran an old school torker on his 289 back in the day, so he wanted to stick with what he’s always ran. Anyways... the Cleveland is a complete monster and can destroy most cars on the street.

I really like the Torker intake. But it was made for a 351 to run up to 7000+ rpm. To hit 600hp NA, I think the engine needs to be 400+ CI, for a reasonable rpm range. The Torker might be enough, but for bigger cubes I would want a little more intake for that big hp. Myself I wanted the Torker for mid range power in a 408 engine(400 bored .030 over). If there was/is an adapter plate to run 4V heads/intake on a Windsor block, I'd love the Torker on a 427 Clevor. With well done Cleveland heads, IMO that should get close to 600hp.
 

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My brother's made 580 out of a 408c. Iron 4V closed chamber heads with some work. 12.2:1 on E85 (carb). I can't think of what intake it was tested with, I think CHI but could be wrong. He's actually changing it over to EFI now. He'll likely lose some HP but hopefully improve driveability. Pretty easy to build one of these, it's all in the heads & intake just like any other engine. I also can't say how accurate (or inaccurate) the dyno was. It's in a '55 customline.

I was originally going to buy the heads from the guy he got his heads from and do a 408"w with those cleveland heads. But then I'd have had to find a set of (custom?) pistons to work, then headers, and an intake. I found it 'easier' to throw together a windsor headed deal, which was supposed to be a 408 but the crankshaft was mispackaged and I couldn't send it back. LUCKILY the guys I got the rods and pistons from were nice enough to let me send THOSE back and exchange them for the right stuff. It was supposed to be a 408 but the crank was a 4.170 stroke, so it became a 427 by mistake.

4v iron closed chamber heads can make some steam but they need some work.
 

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My brother's made 580 out of a 408c. Iron 4V closed chamber heads with some work. 12.2:1 on E85 (carb). I can't think of what intake it was tested with, I think CHI but could be wrong. He's actually changing it over to EFI now. He'll likely lose some HP but hopefully improve driveability. Pretty easy to build one of these, it's all in the heads & intake just like any other engine. I also can't say how accurate (or inaccurate) the dyno was. It's in a '55 customline.

I was originally going to buy the heads from the guy he got his heads from and do a 408"w with those cleveland heads. But then I'd have had to find a set of (custom?) pistons to work, then headers, and an intake. I found it 'easier' to throw together a windsor headed deal, which was supposed to be a 408 but the crankshaft was mispackaged and I couldn't send it back. LUCKILY the guys I got the rods and pistons from were nice enough to let me send THOSE back and exchange them for the right stuff. It was supposed to be a 408 but the crank was a 4.170 stroke, so it became a 427 by mistake.

4v iron closed chamber heads can make some steam but they need some work.

Cleveland pistons are unique like TW pistons are, but the pin height is variable like any Windsor pistons, though less common. You should have hunted around to see what Cleveland pistons were available. Given a stroker crank, you needed to research the piston height anyway.


A Windsor is only 1/4" taller block than a 351C, so any Cleveland headers are possible to work in a Clevor application.


Given the differences of the old 70's accessories, and late Windsor serpentine front dress, I'd try hard to build a Clevor with a long stroke. That's the easiest method to success with the Cleveland heads, and minimize swapping issues.


The tough part is still the rare choices of intakes, headers, and Cleveland heads.
 
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