Cleveland heads were ALL TOO SWEEEEEEEEEET ...

 

Was refering to parallel valve heads, but anyways...

Did factory cleveland heads flow 300 cfm? I'm not a fan of old stuff, but the current crop of Edelbrock and CHI stuff is nothing short of awesome. Just imagine if Ford would have considered a modern version of the cleveland for musclecar/truck duty in the battle against Nissodge and GM instead of developing the mod motor.

While techincally a canted valve head, I never really liked the hemi. Sure, its got the whole unshroud the valve thing, centrally located spark plug, and minimal surface area going on, but it lacks any sort of useful quench area.

 

Yeah, those 4bbl Cleveland heads were monsters, ports big enough for a very healthy full-sized big block but put on 302(Boss) or various 351 motors. I don't think the performance potential of these heads, or the Cleveland 351, were ever truly plumbed, though the Boss 302 and 351 did give some indication of the remarkable potential in waiting.

In other engine news, it does seem as if 400hp is the new 300hp in the engine-bay fashion world. Lexus is releasing their new FX50 SUV thingy and it's sporting a, guess what, 390hp 5.0 V8 to add to the burgeoning throng of 400hp-class four to five-liter V8s.

 

I think the reality is that existing and upcoming V6 engines, both in naturally aspirated and turbo trim, have become so powerful that small V8's were forced to up the ante to maintain their relevance. And I'm glad to see it.

 

Don't forget a TT V6 may COST more than a V8 to produce...
...therefore I don't see the TTV6 being in anything but an SE model.

 

Orignal factory 4V heads flowed 300+. There really wasn't anything you could do to the intakes to improve them other than polish up the ports. One problem with them was the intake ports were too large for most street engines which cost low end torque. More power could be obtained by raising up the exhaust ports, but that cost a lot of $$. I believe Roush came up with the exhaust port rework for his drag engines back in the 70s.

I tried a couple different aftermarket intakes on my Clevelands, Offenhouser Dual-port which has separate runners for the primary and secondary carb barrels, greatly improved low end, sacraficed high end. Also tried an Edlebrock AL copy of the standard Ford 4V dual plane intake, that had smaller runners to up the air velocity, not as much low end as the Offenhouser but had about as much top end as the standard for Manifold.

The original factory 2V heads were no slouches. I don't have the exact #s, but they flowed more air than any factory Windsor head including the GT40s. I never understood spending $$ on Windsor stuff, to me you'd be better dropping in a Cleveland or adapting Cleveland heads to your Windsor block.

I've lost track of the latest aftermarket developments as I sold all my old cars and Cleveland stuff 5 years ago. Looks like those "3V" after maket Cleveland heads are shooting for the best compromise in flow & velocity for most applications.

Hemis have lots of combustion problems, the plus aren't centrally located and the hemi combustion chamber has HUGE surface area so the burn doesn't reach the other side of the head dome leaving large amounts of raw fuel spitting out the exhaust. Hence 2 plugs in the modern drag hemis and new generation street Hemi. One of the things that killed the 60s hemi was it was impossible to make them meet even the loose 70s emission regs. given the low tech back them. If you ever were around the old hemis in the day, their exhaust fumes could knock you out.

 

Given that Ford's NASCAR engine is based on the old Cleveland head design, Roush used Cleveland style heads in all his Trans-Am and other road race cars, the Daytona 24 hour was won 2 times by Cleveland head engines (along with many other many other IMSA prototype wins by Dyson racing with those engines) and the Panoz race cars used Cleveland heads, I'd say the potential of the Cleveland has been reached.

Unfortunately when Ford pulled out of racing in 72 and dumped the performance stuff for the Cleveland, it was tough going for a number of years as the big time racers like Roush and aftermarket companies had to work out the Cleveland's problems such as bottom end oiling and valve spring fatigue.

 

Cheap, and readily available. Especially in the 5.0 era, it would have been a major undertaking to adapt a cleveland head to an EFI 5.0 and when the ball really got rolling you had windsor heads capable of flowing as well as the cleveland units with more modern port and chamber designs.


CHI and Edelbrock are the two that come to mind and they feature revised combustion chambers and sane ports sizes as you've mentioned, It would be really nice if say Edelbrock offered an EFI lower that would work with thier canted valve heads.