Timing
 

What timing are you guys running with these heads? I’m at 32 total. 10.1 compression on 94 gas.

Engine Quest does not have any BBC heads in their 2023 catalog....unless I totally missed them.
But I can't find them anywhere for sale. Seems likely that another cast iron product went the way of Covid shutdowns.

I've heard that marine use BBCs can be hard on seats...and the powdered seats last longer?

Is there any worthwhile cast iron aftermarket heads available?

Or just go Promaxx 317...for $750 ea bare? Again....seat issues.

I have 088s now, and want to get away from the poor ex ports...a lot to ask to scavenge a blower fed 454.

So, are you suggesting that the aluminum ProMaxx 317cc heads have seat issues as well???

Also, justt so you know, I have been in JimV's shop and have seen what Jim Valayko can do on the GM cast iron exhaust ports...even from 20 years ago...he might be worth a phone call.

Kaama, really appreciate the Int on JimV and cast ex ports.

Chad Speiers did some 088 heads up for a tractor pull engine or something like that.
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I'll inspect my 088 heads, and see what they need to run. I'll probably just do some mild cleanup and the obvious.

Powdered seats can have metallurgical elements added that would not mix into a casting. They're softer to start and machine, but they work harden with use. A lot of OEM have gone with powered seats.

Flotek heads come with powdered seats.
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Promaxx has regular seats...not sure if they would add powdered if requested.

I was leaning to the Promaxx, but the Floteks I think are essentially the same head casting.

Floteks oval port flows considerably more than the others. Never compared the rectangular ports. I've not heard of any complaints on Floteks either. Forget intake volume. CC doesn't matter as much as flow. A good flowing small port will out perform a lesser flowing larger CC port in the RPM range of a marine engine.

Great Eric Weingartner video on Promaxx 290 and 317 heads on a 496 dyno comparison.

These are essentially the same castings as Floteks.

He milled the 317s to have the same chamber size as the 290s for same compression.

317s made a bit more power in the low rpm and peak rpm.

Definitely interesting.

I don't believe they are essentially the same casting. The Flowtek's have lazy exhaust ports compared to the Promaxx. The 317 is closer to an AFR 315 on the back to back flow bench racing I have seen on Super Flow 600's.

Yeah its a stretch to say the flotek is as nice as a promax, at least in my limited experience with them. Customer had some flotek cnc heads on a 555 on my dyno, he had bought them from them turn key (I did NOT build this engine or pick out the parts, was strictly a dyno job) first issue is the guideplates they provided allowed the pushrods to bottom out and severly rub/bend as it cycled thru lift. Owner should have caught that when assembling but comp guideplates were at least .050 deeper at bottom of slot and had no issue. Down the road he had issues with valve guides wearing quickly, machine shop said they were cheap, soft garbage when they changed them. now this was at least 5 years ago, maybe they stepped up their game since then too. Ive now had at least 10 sets of promax heads thru my hands/on dyno, some I installed some that came here on stuff in past 5 years and overall they are a really good head for being a chinese imported, good enough that I just did a WD buy in on them as AFR heads have went insane on price and very few guys will spend that much.

Eric does some vids on the castings. Apparently they come from the same foundry and castings.

They'll be different in how they get seats and valve jobs etc. That may be where you get the exhaust variation.

Pretty sure the Floteks did pretty well on ex flow. He doesn't use a pipe.

I was leaning to Flotek because of their powdered seats. But if they need 2.30 valves, then I have to re-think that. I have virgin 454 bores.

I'm all ears on the Flotek ex port issue. I have 088 BBC heads, so a SBC ex port would be an improvement.

Going to flow test flotek 290cc with ferrea 6000 valves i few weeks.