Don Terrill’s Speed-Talk

Has anyone flowed the AFR220 SBF head on a 4.00 bore? The intake flow on a 4.155 bore is 338 @ .800 lift. Does the 2.100 intake valves hurt the flow significantly on a smaller bore? I emailed AFR tech and they couldn't answer that question.

Joe

If they ( AFR) have not researched the use of that valve size in the Bore size your asking about for your motor then you can assume this!
The unshrouding work needed in the chamber along with its change in chamber shape and loss of compression to make use of a 2.100" means that any possible gain in air flow is off set too much by what I posted here in this paragraph before!

Also concider this, on a well built race motor 315 intake cfm @28" better already be making you 680 to 700 hp, so if your not already at that hp level now then look somewhere else in your motor for greater power then a larger Intake valve!

mag2555 wrote: ↑Sat Mar 10, 2018 6:57 am If they ( AFR) have not researched the use of that valve size in the Bore size your asking about for your motor then you can assume this!
The unshrouding work needed in the chamber along with its change in chamber shape and loss of compression to make use of a 2.100" means that any possible gain in air flow is off set too much by what I posted here in this paragraph before!

Also concider this, on a well built race motor 315 intake cfm @28" better already be making you 680 to 700 hp, so if your not already at that hp level now then look somewhere else in your motor for greater power then a larger Intake valve!

Just asking if anyone has flowed SBF AFR220 heads on a 4.0 bore. They come from AFR with 2.100 valves.

Autopart101 wrote: ↑Sat Mar 10, 2018 7:47 am

mag2555 wrote: ↑Sat Mar 10, 2018 6:57 am If they ( AFR) have not researched the use of that valve size in the Bore size your asking about for your motor then you can assume this!
The unshrouding work needed in the chamber along with its change in chamber shape and loss of compression to make use of a 2.100" means that any possible gain in air flow is off set too much by what I posted here in this paragraph before!

Also concider this, on a well built race motor 315 intake cfm @28" better already be making you 680 to 700 hp, so if your not already at that hp level now then look somewhere else in your motor for greater power then a larger Intake valve!

Just asking if anyone has flowed SBF AFR220 heads on a 4.0 bore. They come from AFR with 2.100 valves.

I'm sure someone has done it but not many would care what the results were when the head was originally designed for a big bore motor in the first place.

Bigger valves which provide more peak air airflow(usually over the long side smashing into the combustion chamber/bore) at the expense of further reduced flow in some other portions of the curtain area have been well proven to produce 0% gain or even net power losses on real running motors. The prerequisite blown out chamber walls needed to get there also kills some of the chambers pressure recovery characteristics as well.

And the one's that do make much more power comes at the expense of average power production leading to peaky 5 speed manual type powerbands. Otherwise we would all have been running the biggest valve that would possibly fit into an OEM head and aftermarket heads wouldn't have flourished as much as they have through the years. Forgetting the short sides flow quality is a mistake IMO, which has seemingly lead us towards shallower valve angles to shore up the curtains weakest link. Quantity of flow is good but there's still heavy fuel mass fuel involved so we must also focus on the quality of that flow too.

I recently had an older 220 head with a 2.08" intake on a 4.030" bore. Engine made 696 hp with a Victor intake, dominator, big roller cam and 12.5 compression

Clay radius on the intake, no pipe on the exhaust

jcisworthy wrote: ↑Sat Mar 10, 2018 12:24 pm I recently had an older 220 head with a 2.08" intake on a 4.030" bore. Engine made 696 hp with a Victor intake, dominator, big roller cam and 12.5 compression

Thanks. Looks like the smaller bore didn't impact the flow at all. I have a set of the newer afr220s. I'm using them on a stock block 427. 11-1 Edel. 2828 intake 1050 carb 260/265@.050 SR cam. Hope We hit the 650 range.

That was a 408 stroker engine

I ported a set of factory LS3 heads and flowed them on a small and large bore with virtually the same numbers

I have seen Cleveland heads on the bench pick up on lager bores

Chamber deshrouding for a larger bore application would probalby lose some air on a smaller bore but the smaller chamber, at lease in some applications, does not seem to care what size bore it is on

Autopart101 wrote: ↑Sat Mar 10, 2018 7:47 am

mag2555 wrote: ↑Sat Mar 10, 2018 6:57 am If they ( AFR) have not researched the use of that valve size in the Bore size your asking about for your motor then you can assume this!
The unshrouding work needed in the chamber along with its change in chamber shape and loss of compression to make use of a 2.100" means that any possible gain in air flow is off set too much by what I posted here in this paragraph before!

Also concider this, on a well built race motor 315 intake cfm @28" better already be making you 680 to 700 hp, so if your not already at that hp level now then look somewhere else in your motor for greater power then a larger Intake valve!

Just asking if anyone has flowed SBF AFR220 heads on a 4.0 bore. They come from AFR with 2.100 valves.

Not that particular head but, I have flowed a 2.100" intake valve using a 4.042" bore with a "Yates" C3 head" having great success; (those heads do not have splayed valves).

On a 4" bore,,
Afr 220cc cnc port 58cc chamber.

.100 - 67 in / 55ex
.200- 139in / 102 ex
.300- 204 in / 144 ex
.400- 251in / 181 ex
.500- 274 in / 200 ex
.550- 281 in / 206 ex
.600- 287 in /210 ex
.650- 293in / 215ex
.700- 300in / 216ex
.750- 306in / 217 ex
.800- 312 in
.850- .315 in

cjperformance wrote: ↑Sun Mar 11, 2018 7:47 pm On a 4" bore,,
Afr 220cc cnc port 58cc chamber.

.100 - 67 in / 55ex
.200- 139in / 102 ex
.300- 204 in / 144 ex
.400- 251in / 181 ex
.500- 274 in / 200 ex
.550- 281 in / 206 ex
.600- 287 in /210 ex
.650- 293in / 215ex
.700- 300in / 216ex
.750- 306in / 217 ex
.800- 312 in
.850- .315 in

That's a big difference than the above flow chart. Yes difference size valve but wow.

What are you looking at as a combo/application for use of these heads?

cjperformance wrote: ↑Sun Mar 11, 2018 10:19 pm What are you looking at as a combo/application for use of these heads?

427- Stock block 4.040 bore 4.170 stroke. 11-1cr cam SR 260-265@.050 .700 lift. edel 2828 intake 1050 carb. I have p/n AFR1451 SBF220. I thought they flowed better than that. AFR claims 334 @ .700 lift. I Know AFR flowed in on a big bore 4.155. Didn't think the smaller bore would drop 30 cfm.

Autopart101 wrote: ↑Sun Mar 11, 2018 11:13 pm

cjperformance wrote: ↑Sun Mar 11, 2018 10:19 pm What are you looking at as a combo/application for use of these heads?

427- Stock block 4.040 bore 4.170 stroke. 11-1cr cam SR 260-265@.050 .700 lift. edel 2828 intake 1050 carb. I have p/n AFR1451 SBF220. I thought they flowed better than that. AFR claims 334 @ .700 lift. I Know AFR flowed in on a big bore 4.155. Didn't think the smaller bore would drop 30 cfm.

You could always just use .030" offset dowels to move the head over some if you think you need to get the intake valve head further from the bore wall.

Walter R. Malik wrote: ↑Mon Mar 12, 2018 10:35 am

Autopart101 wrote: ↑Sun Mar 11, 2018 11:13 pm

cjperformance wrote: ↑Sun Mar 11, 2018 10:19 pm What are you looking at as a combo/application for use of these heads?

427- Stock block 4.040 bore 4.170 stroke. 11-1cr cam SR 260-265@.050 .700 lift. edel 2828 intake 1050 carb. I have p/n AFR1451 SBF220. I thought they flowed better than that. AFR claims 334 @ .700 lift. I Know AFR flowed in on a big bore 4.155. Didn't think the smaller bore would drop 30 cfm.

You could always just use .030" offset dowels to move the head over some if you think you need to get the intake valve head further from the bore wall.

Yes offset dowels may help out. Still going to be a good strong combo either way.