afr 195 or 210 ?

[groberts101]

Just trying to help you, and the rest of the board for that matter.
All you want to do is argue instead of learn. You must know everything already?!?
We have a saying around here....."all we do know, is that we don't know".
I'm guessing if myself and my colleagues don't know it all, with the experience and resources we have, you have a ways to go yet!
Don't take it as a jab, as I said, I'm trying to help you!

Thanks.. I do need help! Probably much more than Gary does too.

Here's a question I posed in another thread. An extreme example compared to this thread port differences but maybe still shows a small cross section of what happens to a power curve when port size changes between various castings?

Seems that despite most thinking/saying heads and cam's aren't some kind of magic voodoo.. there sure is a lot of debate about them. Maybe some people are inherently more experienced and voodoo literate than others? Then consider the amount of time and resources that go into changing them out and refining the combo on the dyno and it sure seems to be much more difficult to nail an optimum result than some are admitting or letting on about. So ,all that math and estimation of final results don't mean squat until mother nature has final her say in the matter.

Can some of the smarter guys, who hopefully just hate koolaid and not me personally, help me build a paper motor to help better understand how flowZ in relation to CSA(and mCSA) can affect the optimum cam choice?

Let's say I call up a custom cam grinder and tell him I have a 302" SBF street/strip type deal and give all pertinent components(lighter weight 8mm hollow valves, conical springs, Ti retainers, etc), induction, exhaust, chassis weight, tire/gearing, and personal taste or bias of what I can and prefer to live with on the street side of the equation. And based on that info we both agree that a peak horsepower mark should likely fall into the 6,800 rpm range. And that's just peak.. maybe it needs to go/hang on upwards of 7,200 on the shift to ET better.

But wait.. there's more! lol Then I also tell him I have 2 sets of fairely well developed/modified cylinder heads to choose from and haven't yet fully decided which ones will be used.. so grind me 2 cams to suit each specific combo of parts. One set being a smaller CSA/higher velocity port design with peak airflow possibly better matched to the displacement and rpm capability of this shortblock.. the other being a much larger port CSA/slower velocity and far exceeding this OEM shortblocks capability before cracking or splitting in half.

1st set is an RHS 165cc casting that has been rolled over another degree(19°) with welded and moderately raised intake and exhaust ports, with the exhaust port also being plated/extended/angled upwards and shrunk down to accept/match a 1.5" od(1.370") primary pipe coming off the flange, with intention of stepping towards 1.625" od and hitting a merge style collector. Valve sizes are 1.96"/1.54" with 90+% throats.

2nd set is also fairly well developed, a high-port converted Kaase P38 head with MUCH bigger CSA and having mod's very similar to the above RHS's, with the exception of the exhaust ports being matched to a 1.625" pipe off the flange and stepping to 1.75" before heading towards a slightly smaller merged collector choke sizing. valve sizes are 2.16"/1.55" with 87/89% throats.

So finally onto the $10,000 question. Does each custom cam grind he comes up with end up with similar spec's for either head used on this combo?

Because if it does?.. most would naturally think that without even seeing those final cam spec's that the Kaase P38 headed combo will surely give up torque down low and make power WAAAYYYY past the expected peak rpm. And maybe even moreso if that cam matched to work with the RHS headed combo had a relatively fast ramp rates and higher ratio rockers?

[groberts101]

Am I not suppose to respond to someone that is talking to me? Why do you have to interupt? No one was talking to you!

You really should ask more questions and listen to the answers instead of letting your emotions get the best of you. You would further your understanding of engines.

a lot of people here.

What about you? Can you help me out with head and cam choice and offer some other variables to consider?

[GARY C]

Sounds cool. Have you picked a cam yet? Maybe start a thread. Lol. This site needs some excitement, it's getting stagnant in here.

I haven't sorted the cam as of yet, i would start a new thread but think it will cause a ruckus like this one. I think ill just go back to lurking from afar....lol

It's all fun and games you just have to jump in with both feet.
You can contact Cam King (Mike Jones) on here if you are not sure on cam selection.
I like off idle drivability and power brakes so I am more conservative then those chasing dyno numbers.
My Pontiac 400 4spd has a 222/226 @ .050 on a 108 LSA with a 1.65 rocker with a ported factory 6x head and a 2.110 valve, it idles clean at about 775 rpm and pulls 14" vacuum
If I was building your engine I would go with a 226/232 on a 108 with a 1.6 int and a 1.5 ex rocker but thats just me.

I will move the engine info back up so people can skip page 10.

AFR has 2 195's a 2.05 valve and a 1.905 and a 2.08 valve with a 1.920... they have 2 210's both with 2.08 valve, one has 2.1 and the other has a 2.115.
As I said earlier I would take the 195 with the 2.08 and open up the min cs to have a more consistent size runner and you would probably be at 205 cc... my understanding is that cross section is more important than cc's or so I have heard.

[groberts101]

I haven't sorted the cam as of yet, i would start a new thread but think it will cause a ruckus like this one. I think ill just go back to lurking from afar....lol

It's all fun and games you just have to jump in with both feet.
You can contact Cam King (Mike Jones) on here if you are not sure on cam selection.
I like off idle drivability and power brakes so I am more conservative then those chasing dyno numbers.
My Pontiac 400 4spd has a 222/226 @ .050 on a 108 LSA with a 1.65 rocker with a ported factory 6x head and a 2.110 valve, it idles clean at about 775 rpm and pulls 14" vacuum
If I was building your engine I would go with a 226/232 on a 108 with a 1.6 int and a 1.5 ex rocker but thats just me.

I will move the engine info back up so people can skip page 10.

AFR has 2 195's a 2.05 valve and a 1.905 and a 2.08 valve with a 1.920... they have 2 210's both with 2.08 valve, one has 2.1 and the other has a 2.115.
As I said earlier I would take the 195 with the 2.08 and open up the min cs to have a more consistent size runner and you would probably be at 205 cc... my understanding is that cross section is more important than cc's or so I have heard.

In one of my posts last night to cab0154.. I obviously confused some numbers being used here between mCSA and CSA. My apologies.. should have asked what area he was using before questioning his numbers.

[GARY C]

It's all fun and games you just have to jump in with both feet.
You can contact Cam King (Mike Jones) on here if you are not sure on cam selection.
I like off idle drivability and power brakes so I am more conservative then those chasing dyno numbers.
My Pontiac 400 4spd has a 222/226 @ .050 on a 108 LSA with a 1.65 rocker with a ported factory 6x head and a 2.110 valve, it idles clean at about 775 rpm and pulls 14" vacuum
If I was building your engine I would go with a 226/232 on a 108 with a 1.6 int and a 1.5 ex rocker but thats just me.

I will move the engine info back up so people can skip page 10.

AFR has 2 195's a 2.05 valve and a 1.905 and a 2.08 valve with a 1.920... they have 2 210's both with 2.08 valve, one has 2.1 and the other has a 2.115.
As I said earlier I would take the 195 with the 2.08 and open up the min cs to have a more consistent size runner and you would probably be at 205 cc... my understanding is that cross section is more important than cc's or so I have heard.

In one of my posts last night to cab0154.. I obviously confused some numbers being used here between mCSA and CSA.

One of the difficulty for me is all theses guys will tell you how important cs is but the only thing they will quote if any is min cs, everyone on this thread pushing the 210 forgot to tell the OP that their are 2 and which one he should use.
From what I have seen is when you get into a bigger 23* head the min cs may be good but the rest of the head is likely to be too big for a constant cs, I am by no means a pro but I have found that by starting with the smaller head you have room to tweak but on a street car with a big head your just stuck with a big head.
EDIT! The other issue I see with most cs reference is based on WOT max Hp at a given rpm, that is fine for a race engine but it does not address everything below that peak number at part throttle and low air speed.

[Frankshaft]

We were giving 2 choices. Of the 2, knowing what I know about both choices, I chose the 210. Again, doesn't need to be over complicated. You just like to argue to argue it seems. If I said left, you would say right, if I said up you would say down. If it was mine, I wouldn't use either one actually. Lol.

[GARY C]

We were giving 2 choices. Of the 2, knowing what I know about both choices, I chose the 210. Again, doesn't need to be over complicated. You just like to argue to argue it seems. If I said left, you would say right, if I said up you would say down. If it was mine, I wouldn't use either one actually. Lol.

Which 210? there are 2 of them?

[groberts101]

I will move the engine info back up so people can skip page 10.

In one of my posts last night to cab0154.. I obviously confused some numbers being used here between mCSA and CSA.

One of the difficulty for me is all theses guys will tell you how important cs is but the only thing they will quote if any is min cs, everyone on this thread pushing the 210 forgot to tell the OP that their are 2 and which one he should use.
From what I have seen is when you get into a bigger 23* head the min cs may be good but the rest of the head is likely to be too big for a constant cs, I am by no means a pro but I have found that by starting with the smaller head you have room to tweak but on a street car with a big head your just stuck with a big head.

Yeah, I feel ya' there. Everyone has enough time to be a critic but never enough to explain in physical detail as to why they are disagreeing. Lots probably boils down to bias and lack of patience and time I guess too.

It has been my personal experience that a head with slightly too small mCSA(MIMIMUM cross section area) at the pinch.. but having a larger more generous cross sectional expansion into and over the short turn is much more tolerant and livable than just the opposite of bigger mCSA and smaller expansion/narrower short turn.

Dunno, maybe that's what these guys were saying all along without actually saying it?

[Frankshaft]

We were giving 2 choices. Of the 2, knowing what I know about both choices, I chose the 210. Again, doesn't need to be over complicated. You just like to argue to argue it seems. If I said left, you would say right, if I said up you would say down. If it was mine, I wouldn't use either one actually. Lol.

Which 210? there are 2 of them?

Flip a coin. Lol. Thanks for proving my point. You referring to the normal 210, and the competition port head? Flip a coin, it wouldn't matter. Although, if he chose the comp ported version, they flow more thru the same cross section, so it would be better yet.

[GARY C]

We were giving 2 choices. Of the 2, knowing what I know about both choices, I chose the 210. Again, doesn't need to be over complicated. You just like to argue to argue it seems. If I said left, you would say right, if I said up you would say down. If it was mine, I wouldn't use either one actually. Lol.

Which 210? there are 2 of them?

Flip a coin. Lol. Thanks for proving my point. You referring to the normal 210, and the competition port head? Flip a coin, it wouldn't matter. Although, if he chose the comp ported version, they flow more thru the same cross section, so it would be better yet.

Actually the have a different cross section so what is different to keep them at a 210cc.

[Frankshaft]

Your lost. Truly.

[GARY C]

In one of my posts last night to cab0154.. I obviously confused some numbers being used here between mCSA and CSA.

One of the difficulty for me is all theses guys will tell you how important cs is but the only thing they will quote if any is min cs, everyone on this thread pushing the 210 forgot to tell the OP that their are 2 and which one he should use.
From what I have seen is when you get into a bigger 23* head the min cs may be good but the rest of the head is likely to be too big for a constant cs, I am by no means a pro but I have found that by starting with the smaller head you have room to tweak but on a street car with a big head your just stuck with a big head.

Yeah, I feel ya' there. Everyone has enough time to be a critic but never enough to explain in physical detail as to why they are disagreeing. Lots probably boils down to bias and lack of patience and time I guess too.

It has been my personal experience that a head with slightly too small mCSA(MIMIMUM cross section area) at the pinch.. but having a larger more generous cross sectional expansion into and over the short turn is much more tolerant and livable than just the opposite of bigger mCSA and smaller expansion/narrower short turn.

Dunno, maybe that's what these guys were saying all along without actually saying it?

Chad layed out some good math hear years back about sizing the head from the min cs to the short turn as well as bowl size, Use to have it saved but haven't looked for a while.
It's good info to have but it is still dealing with peak power race engine and would most likely not be good for rpm below that.

[GARY C]

Your lost. Truly.

If you increase one cross section on a 210cc head is it still 210cc if you don't reduce it somewhere else. My guess is that the bigger msc 2.115 is probably more consistent of a runner to stay at a 210cc and a probably the better choice of the 2 but just pushing cc's can be misleading.

[Frankshaft]

Which 210? there are 2 of them?

Flip a coin. Lol. Thanks for proving my point. You referring to the normal 210, and the competition port head? Flip a coin, it wouldn't matter. Although, if he chose the comp ported version, they flow more thru the same cross section, so it would be better yet.

Actually the have a different cross section so what is different to keep them at a 210cc.

Lol, 2.100 vs 2.115. The difference is the finer step over on the program. Otherwise it's just a more refined port, that flowz a little more thru a tiny difference in cross section. Typical though, again, you need to argue to argue. And by the way, it wasn't Chad, it was Larry Meaux. I can argue to argue too. It's kinda fun trolling a troll.

[zums]

Flip a coin. Lol. Thanks for proving my point. You referring to the normal 210, and the competition port head? Flip a coin, it wouldn't matter. Although, if he chose the comp ported version, they flow more thru the same cross section, so it would be better yet.

Actually the have a different cross section so what is different to keep them at a 210cc.

Lol, 2.100 vs 2.115. The difference is the finer step over on the program. Otherwise it's just a more refined port, that flowz a little more thru a tiny difference in cross section. Typical though, again, you need to argue to argue. And by the way, it wasn't Chad, it was Larry Meaux. I can argue to argue too. It's kinda fun trolling a troll.