We did a 390 engine about a year and a half ago that was 397 cubes, 3.78 stroke, iron C4AE-G heads, single carb, .570 lift cam, and 10.45 to 1, that made 622 hp on Bischoff's dyno.  I reckon it just depends on how you go about it, and how you plan to use it.

So I just read this thread.  I'm not going to try to sell my heads on here.  A person should do research and make an informed decision.  "Patrick CNC" can't accurately describe a pimple on an elephant's ass of all of the different programs we have.  I have revised the "Street Pro Port" seven times over the course of the time Edelbrock has been doing those castings.  When a person comes here for heads, the first things to figure out are budget, and how they intend to use it.   From there, I try to inform them to the best of my ability and do something to maximize their "bang for the buck".  There are five intake ports, two exhaust ports, and two combustion chambers that we generally sell in Ed Pro Port castings when selling cylinder heads or top end packages. I have a few other ports that we use in class legal or max effort race apps, that are cost prohibitive.......if not working within rules, it just isn't a sensible way to go.

"Street Pro Ports" have stock MR location intake and exhaust flanges.  I don't advertise numbers.  I sell heads that work.  Just for information purposes, I had Bischoff flow a Street Pro Port as a "3rd party".   320 at .500, 347 at .700.  Exhaust 240-ish in the stock location.  I don't need to go into any more detail here, but the ports are in the MR location, and they don't look like anything else mentioned here, and they do not cost $6K.  $4200 is current pricing for standard seats and 72cc chambers.  From there, there are MANY options. It is possible to get Econo Pro Ports for $3500, or max effort class-legal heads that are 15K. Raised and relocated exhaust ports flow 255 to 280 depending on port and valve size.  It all depends on goals and use. From 55cc chambers, to Oval Port and High Riser intake ports that will flow 400+ cfm, depending on where they are flowed.  I never see more than 390 here on any of my ports, but other folks have benches that read higher than mine.

We also work on many other brands of heads.  We just finished R&D on the next generation BBM heads. They are better than current offerings with only a 2.100 intake valve, and notably superior to any current stock location shelf available heads with the optional cnc package. They should be available in the Fall. 


Posted for information and clarification.  I'm not sure why every topic in which my stuff is mentioned always results in one or more experts on here, without fail, making false assumptions or misleading statements about my junk.  Sometimes there are trade-offs to accomplish goals.  Often, a max flow number is given up to get more meat where it needs it.  Sometimes ports are smaller, with high velocity by design, so quoting a flow number doesn't tell the whole story.  If you just buy a flow number, you may not get what you need.  Lots more to it. 
BP.

You should add the Fel Pro 8045 PT and the 9061 PT.  Heavy duty truck gaskets.  They will compress to .051 and .061, respectively.  Not quite round, but mostly a 4.200 bore.  Very good gaskets.

Most of what you read and hear of Canadian heads is laced with bad info and folklore.  They did exist.  There were 50 sets.  They were absolutely better, but after NHRA learned how to ID them, they carried a weight penalty.  Before porting, they were still better even carrying the weight, and allowed some cars to run classes that small N heads couldn't fit.  When porting came to Super Stock, the Canadian heads we're/are allowed 173 cc, where the regular N are 155 cc.  They are still competitive today.  I have ten Canadian heads left.  I might use them again, so I don't sell them.  If the Edelbrock factors ever get real screwed up, they would be real good.  I went 9.37 about 13 years ago with small heads, but the big heads were better.  I had a big head engine in the works when the Edelbrock got approved and I wanted to try those, so my "new" set of Canadian heads have been in the corner for about 15 years.  Unfortunately, no time to do anything with my personal stuff in many years.

Side note: Morgan ran small heads, but he was faster than just about all of the Canadian head cars because he was and is smarter than the others.  Anyone who runs a class Jim is in will have a bad day if Morgan shows up. 

I don't think there is enough bearing surface area with the Honda.  Even the hybrid bearing Honda with SBC width just doesn't have enough load patch area in my opinion.  If it was a drag engine that saw VERY frequent teardown, the Honda might live.  I like the 2" pin for durability. I just think that is about as far as I would go.  I have several with more power and torque running long term with the 2" rods.  As far as overlap, the Crower piece won't give up NA.  It might become an issue with serious power adders, but the crank can take alot.

Eric, I can get past 14:1 with a flat top if I run the chamber program shallow and use a small chamber.  This engine was a little bit of an unplanned mating of a rotating assembly and a pair of heads with the chamber at 72cc.  I don't think the dome, designed like it is, hurt it bad, but it does hurt.  A dish or a small "bump" dome will excite combustion better than just a flat top.  Sometimes we make the valve relief an oval slot and then a small bump rather than a flat with plunge pockets.

Blair, that's outstanding, from a engine that large. 1.67 HP per CI.

Can you tell us the valve size and how much the heads flowed.

This particular one has 2.220 intake and 1.680 exhaust valves.  I didn't intend to turn it real high, so I used the small valves to make torque where it wants to reside rpm-wise.  That makes it real snappy with the inches and 13.5 static.  If I was going to the end with it, more cam, a different set of angles on the valvejob, a 2.300 valve with a little more cross section in the port, would all have added up to quite a bit more power.  It also would change the operating range.  This engine will run for years reliably with a 7K shift point and 7300 through the traps.

The heads flow pretty good.  Nevermind the numbers, as it is only one yardstick of several attributes that matter.

We ran this unit last week.  There was a little more in it, based on past info, but we ran out of time.  Customer was looking for around 800 hp, and 700-ish torque, so when we got past there, we didn't beat it on it too hard.  I had 31° timing in it, but it had a rather large dome by my standards, and a 72 cc chamber.  I usually run much smaller chambers, with just a bump dome, but these heads migrated from another project, so more dome was needed.  I think another 2.5 ° would have shown more power.  I reckon they can test that in the vehicle.

Cubic inch:                 535    (4.345 x 4.500)
Peak Horsepower:    893 at 6500 rpm
Peak Torque:             794 at 5100 rpm
Compression ratio:  13.5:1
Camshaft:                 .700 lift solid roller
Heads:                     BPE   MR Race Pro Port Edelbrock
Manifold:                 BPE modified BBM Tunnel Wedge
Carbs:                       940-ish cfm modified center squirters, inline with factory style linkage.