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-   -   AFR 325 flow sheets.... anyone ever flow these heads? (https://www.offshoreonly.com/forums/general-q/340844-afr-325-flow-sheets-anyone-ever-flow-these-heads.html)

Full Force 01-09-2017 07:39 AM

So SB, I still need a 241/246? That's gonna work?

sutphen 30 01-09-2017 07:40 AM


Originally Posted by SB (Post 4517539)

that was round 1,,I later changed it to something in the 250's.I build to many of these things and confuse all the camshafts up.:Dmy guys are on the race team,,always want to go faster racin.

SB 01-09-2017 07:52 AM


Originally Posted by Full Force (Post 4517542)
So SB, I still need a 241/246? That's gonna work?

That's near the same duration #'s as the other cam FF, but how can I say if one will pull higher than the other ? I can't....not same type lobes (.630 vs .680) so I have no idea how the larger lift works because most in that dur are say .630 and under. Don't take that as more than I said....just have no idea in real life how the larger lift lobes perform.

BTW: I am far from telling you what to use, don't want to be part of any futher mess. Just throwing opinions and ideas in as this is a public thread. I will still say pretty strongly that the 565cid's of prev build did give you an advantage over the 540. Still my IMHO.

MILD THUNDER 01-09-2017 08:00 AM

It should be interesting to see what happens , as it sounds like he is going to longer duration cams.

My hunch, tells me he will make more upper rpm power, and see a slight speed increase. My hunch tells me, that when you have a cylinder head that may be down on port speed, you need to keep the valves open longer, than you would, if say, he had a set of 290 AFR heads on the engine, to get good cylinder filling. Or , when your intake is maybe somewhat restrictive, or exhaust. Sure a head can flow good on a bench, but as we know, that can change when you put the intake manifold on it.

Right or wrong, these discussions are good stuff

MILD THUNDER 01-09-2017 08:03 AM


Quote Originally Posted by sutphen 30 View Post
heres one
canfield 320's unmolested,10.3-1 compression,single plane w/ dominator(brand eludes me now) and unlike the magical 741 engine,the cam we needed was 248,258,ls112,.629",.629".on the dyno w/ dyno headers made 670hp,,with the dana marine exhuast it made 692hp.enoungh to push a 33 sutphen to a constant and easy 93mph.
ignition system was simple small cap hei and truck coil.I told him to ask for 93 gmc 350 truck parts at napa.
But did it have enough torque to carry the boat ? :)

Full Force 01-09-2017 08:06 AM

565's made 600 hp, 660 tq... I went off dyno sheets with my thoughts thinking a when bob said 695tq and 700+ hp, that's why I built what I did, when I asked about 565 many guys said "bad rod angles" my machinist said not an issue, didn't listen to him because I had many others saying different. No reason to keep talking about that.

Originally Posted by SB (Post 4517552)
That's near the same duration #'s as the other cam FF, but how can I say if one will pull higher than the other ? I can't....not same type lobes (.630 vs .680) so I have no idea how the larger lift works because most in that dur are say .630 and under. Don't take that as more than I said....just have no idea in real life how the larger lift lobes perform.

BTW: I am far from telling you what to use, don't want to be part of any futher mess. Just throwing opinions and ideas in as this is a public thread. I will still say pretty strongly that the 565cid's of prev build did give you an advantage over the 540. Still my IMHO.


vintage chromoly 01-09-2017 08:07 AM

At what point can you no longer add more duration without increasing the static compression ratio?

Full Force 01-09-2017 08:12 AM

I wanted 11:1... bill wouldn't let me lol

Originally Posted by vintage chromoly (Post 4517561)
At what point can you no longer add more duration without increasing the static compression ratio?


MILD THUNDER 01-09-2017 09:04 AM


Originally Posted by vintage chromoly (Post 4517561)
At what point can you no longer add more duration without increasing the static compression ratio?

These cam guys love preaching the static compression vs cam topic. They make you think its a go/no go scenerio. I loved when bob M told endeavor32, the crane 741 cam just wouldnt work , and be a turd, in his build, because there wasnt enough static. It does, and it did work, just fine.

Mercurys 420, 440, 525efi, all have low static compression. The 525efi , has a 236/244 cam in it, with like 8.75:1 if i recall. But a 540ci, that has 9.6:1 static, gets 5 more deg intake, and 2 more deg exhaust?

The 525efi idles great, makes plenty of torque.

Heck, i remember back when 9:1 was high compression. In the 70s cars, 7.6:1 statics were common. The stock cam in my 78 Trans am was in the 200* at .050 range. I remember swapping that cam out for a much hotter replica of the Ram Air IV cam if i recall, which was a 230ish plus range duration cam. Compression stayed same. Car picked up a bunch, with the cam, headers, intake, etc. Basically a 16 second smog dog, turned into a mid 13 second car with some minor changes. Was still sub 8:1 static 400ci deal. Slow by todays standards, but damn that thing was a turd in stock form. Embarrasing actually. Lol

Of course the idle was no longer a 400rpm in gear , station wagon idle after the cam change, and she liked some advance at idle. That was when all my high school buddys were rockin 5.0 mustangs , and 5.0 TPI camaros, and the occasional 350 Iroc. That old TA would stomp those guys in those days on the street. Of course that was pre LS1 days, and once I lost to a bone stock SS camaro, I just had to go and buy a new WS6 TA with an LS1.

KWright 01-09-2017 09:07 AM


Originally Posted by MILD THUNDER (Post 4517555)
It should be interesting to see what happens , as it sounds like he is going to longer duration cams.

My hunch, tells me he will make more upper rpm power, and see a slight speed increase. My hunch tells me, that when you have a cylinder head that may be down on port speed, you need to keep the valves open longer, than you would, if say, he had a set of 290 AFR heads on the engine, to get good cylinder filling. Or , when your intake is maybe somewhat restrictive, or exhaust. Sure a head can flow good on a bench, but as we know, that can change when you put the intake manifold on it.

Right or wrong, these discussions are good stuff

I think your spot on with this. Tim good luck in your build I hope it all works out for you. You have had alot of great ideas put forward and I don't believe anybody meant you any disrespect.


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