455HO build by Paul Carter
 

A peak at cylinder heads with more of the build to come later.

Paul flowed these 7F6 heads just as he received them, and then flowed them after he worked his magic with a valve job. The gains in the mid lift area are impressive.

Paul is doing all the other machine work on the engine as well, correcting some wrongs, new custom hydraulic roller, stock 455HO intake and RA manifolds, with dyno time to come after I assemble it.

Couple more pictures of Paul's work.

I'm assuming the heads were previous ported? I don't know of any factory heads that flow ~270 cfm @ .450" lift. That's impressive! My SD Performance ported D-ports don't reach 270 cfm 'til .550".

Nice work on the valve job.

Nice how the flow gets to 258 right away and hangs out at 270.

So maybe the flow will be limited by the cam profile or cam timing.

Yes the heads were ported by Dan Barton. The entire engine was previously done at a shop he was employed at. However the current owner felt the engine didn't run up to his expectations and I was asked to look into it.

For starters I knew it had a poor cam choice in it, and when I started tearing things down and found cheap umbrella seals used on the heads I contacted Paul knowing we were going to get into some machine work. So I disassembled the entire engine and took everything to Paul.

On the heads alone Paul found all kinds of things that were subpar. 2 piece valves were used, no hardened seats installed, and the valve springs were so weak they showed signs of rotating in the pockets. Part of the reason why this engine fell flat at 5,000 rpm.

Paul flowed the heads as he received them, and then got to work. Paul installed new 1 piece valves, new hardened seats and performed a valve job that did wonders for the mid lift flow numbers without hurting the upper numbers (Paul is the man :)). The springs were chosen and setup for the custom hydraulic roller that Paul specified to take advantage of these heads while still remaining streetable and docile enough to work the power brakes and AC.

I'll get into short block details in a few days. Paul found all kinds of issues so we were glad we decided to dig deeper into this thing. I pick the engine up tomorrow and once I have assembly done it will go back to Paul for some dyno time and some new numbers.

:confused:

I believe all valve springs rotate?

Bouncing, I could see as a problem.

:confused:

Paul could explain it better. The bottom line is that these things didn't have nearly enough pressure and weren't setup correctly from the get go.

Thinking of a single pattern cam with that E/I ratio?

Wish I had those heads for a project I’m doing. Where is Paul located at?
SD

Very nice...But that's Paul!

Paul is in Tucson, Arizona. Koerner Racing Engines and Cryo treatment.

I don't know the exact cam specs but it's a custom grind Paul specified. I have an idea. I'd rather have the cam card in my hand and talk to Paul before I spill the beans, or maybe he'll comment on it.

I have a set like these but they flow more air.... I'll send you a PM

Thing is, pretty much all 455s with iron heads fall flat at 5200 RPMs. I have a well ported set of HOs that are already done like what the OP will end up with. My car ETs best when I shift @ 5200-5300 RPM. Just can not get enough air through them. Been a great engine though, retired it after its best ET to date, 10.84 after 28 years.

"Thing is, pretty much all 455s with iron heads fall flat at 5200 RPMs"

Some clarification is in order with that. Do you mean 'stock' unported heads ?

I've had a 4.210" stroke combo with ported factory d-port heads make peak power on the engine dyno above 6000 rpm.


.

Not even true! My old 614 headed 455 made peak hp on the dyno at 6800. Went thru the traps at 7200.

I'd say if it was a D-port.

My stock SD heads I shifted at 6500 RPM and didn't dare to go higher with a stock block.
(and probably hit a few 7000 RPM once in a while)

:)

Dragncar, I'm guessing you must be talking about stock unported D-port heads. We've had a few 455's with D-ports that had no problem at all making power above 6,000 rpm.

This particular build I'm on now clearly has plenty of head to make power above 5,000 rpm. It simply didn't have a camshaft to do it for one, it was basically an 068 cam, and it didn't have valve springs with anywhere near enough pressure, Paul was surprised it would even make it to 5,000 rpm. Not only that, but these are round port heads anyway.

So how do my 220 cfm 164cc D ports spin up to 7000 RPM and still pull?????

Yeah Mike, Same with my other friend Mike whose 455 peaked power at 6000 RPM but only lost 20 HP by 7200 RPM. That engine had 6X-4 heads on it, ported to 250/210. Ran 10.90's in Phoenix on 91 pump gas in a 73 Firebird. Been racing that engine for 10 years now.

And your street car runs 11.40's in Phoenix with crap gas and only 9:1 compression.