afr 205's on stock 302

95Vert383AOD · Mar 17, 2009

clement said:
the cylinder heads make the power. more air and fuel in = more power. the displacement just determines the rpm where the power will be made. saying that an AFR 205 is too big for a 302 is a blanket statement and one that may or may not be true depending on the users desired powerband. i dont know that i would go so far to say that a "smaller head" would be faster because it has a more agressive cam. anyone claiming that a milder cam is a bandaid for a bigger head doesnt fully understand valve timing or cross section and its implications. Judson Massingill runs the school of automotive machinists and for a price will explain these concepts.

Ah i understand...Bigger head means it moves the power band up. So assuming you had the right Pistons to clear valves. Then you could run a radical cam that would allow a 302 to Rev. to 8500. Wouldn't be too nice of a street vehicle. but with like a 4.56 gear and high stall Converter it would make it rev. to that 8500 sweet spot faster and awesome track car. Excuse me if im wrong....ive had a few beers and am not done

But now on the other End you could cram the air in with a super charger meaning the motor wouldnt have to rev. so high because the air it would take 8500rpm to move can be crammed in with less RPM.

Im just pretending i was an air molecule with no place to go ....how would i flow? I would flow at really high RPM's at a .750 lift on AFR 205's bolted to a 302 (Race Block of course)

joel5.0 · Mar 17, 2009

5spd GT said:
With that large of a cylinder head, one will likely need a band-aid to get it to the desired performance.

Some use small intakes on a large cylinder head, or a small camshaft to limit the time (and the when) air can travel into the cylinder.

A matched combination is best.

Second the matched combination is best statement, but why are those heads "too large"? Wouldn't a more aggressive camshaft be a "band-aid" to compensate for smaller cylinder heads?

I've worked on smaller CID engines with dual 1.728" intake valves (the equivalent curtain area of a single 2.02" valve ±) + huge TB ID's (83-70mm) + 80+mm MAF....... on a 238 CID engine, 10.75:1 CR. Cam specs?..... 240°/240° advertised duration (intake timing is variable) and 280HP @6000 RPM (rated)...... is it a "hot rod"?.............. A luxury car set that way by Ford....... and a set of AFR 205 heads with 2.08" intake valves are "too large" for a 302 CID engine? View attachment 266019....

5spd GT · Mar 17, 2009

joel5.0 said:
Second the matched combination is best statement, but why are those heads "too large"? Wouldn't a more aggressive camshaft be a "band-aid" to compensate for smaller cylinder heads?

I've worked on smaller CID engines with dual 1.728" intake valves (the equivalent curtain area of a single 2.02" valve ±) + huge TB ID's (83-70mm) + 80+mm MAF....... on a 238 CID engine, 10.75:1 CR. Cam specs?..... 240°/240° advertised duration (intake timing is variable) and 280HP @6000 RPM (rated)...... is it a "hot rod"?.............. A luxury car set that way by Ford....... and a set of AFR 205 heads with 2.08" intake valves are "too large" for a 302 CID engine? View attachment 266014....

Apples to Oranges.

Two intake valves act VERY different than one 2.02" valve.

Did I bring up anything about a 2.08" being to large? What about the possiblity of valve/cylinder wall air flow interference? What about the amount of material that would need to be removed with a stock forged/hyper piston?

Would not, the camshaft specs have to be a band-aid because of the limited clearance/cutting that could occur to fully utilize an AFR 205 cc head.

Do the MCSA, velocity profiles, shapes, curves, etc. have any effect on what an engine needs?

How accurate are advertised numbers? Let's get a scope of the entire lobe to peak lift.

Would not that variable valve timing help with it's "low-end" and supplement the high end as well? Can you have your cake and eat it to, with variable valve timing?

Small plenums = large TB's + intake tract and vice versa. By the way, who brought up TB's? Does one not realize that they are not at all related to a CARB?

What is the point of the tapered TB?

I would hardly call the Lincoln LS a luxury car. Rented one, one time.

Who said it is to large? Is this taking comment out of context?

jwzg · Mar 17, 2009

jwzg said:
...if I have to run less than optimal cam specs from a performance standpoint just to get around smacking the valves, that just doesn't make a whole lotta sense unless I simply want to run something different.

"Optimal" depends on what you are trying to accomplish... If you really want to get the most out of those 205's, build a 347-408 and be done with it. Putting these heads on a 302 is not going to be easy nor very efficient, though it can be done.

I think that's the first time I've ever quoted myself.

clement · Mar 17, 2009

5spd GT said:
The total intake trac makes power, not just the cylinder head. You are missing ~50-75% of the runners, in just considering the cylinder head.

More air does equal more power, if actually used.

hmmm. what would make it so the air is not used? the cam? the intake runners restricting flow or creating turbulence? lack of piston speed? if the intake runners help to increase the airflow by the heads why dont you explain how?

The top-end can also determine where the power will be made.

the head MCS will determine max piston speed it can support. the intake will not magically make the head support more piston speed. the chain is only as strong as the weakest link. i think you are simply too smart to not understand this. when you claim otherwise i wonder what your motives are.

This is true, but let's be honest. How many guys are on stangnet with 8,000 RPM goals?

this statement explains why so many peoples heads/cam/intake 302s run 12.20s when the technology is out there to make them run low 11s with an increase in trap speed, with better driveability, and a wider powerband. but whatever....

Why not? Do you believe that in every case that a large cylinder head/small camshaft is the best case scenario in all scenarios?

if you mean that given the larger head is still in the target port cross section for the powerband and displacement, then yes. this is what the manufacturers have been doing for a decade now.

Who said, a mild camshaft? I hope you are not just comparing .050" numbers or lift numbers. This is a fraction of the importance. It is the lobe that determines the mildness. But then again, what is "mild."?

you said

a small camshaft to limit the time (and the when) air can travel into the cylinder.

so i paraphrased that as "mild" because these types of cams tend to be what most people describe as such. just because a cam has less duration doesnt mean less air will enter the cylinder.

Do you? Does anybody FULLY understand?

i completely agree. no one does. but there are some basic physics principles here that are easily understood rather then relying on 25 year old myths.

joel5.0 · Mar 17, 2009

5spd GT said:
The total intake trac makes power, not just the cylinder head. You are missing ~50-75% of the runners, in just considering the cylinder head.

More air does equal more power, if actually used.

The top-end can also determine where the power will be made.

This is true, but let's be honest. How many guys are on stangnet with 8,000 RPM goals?

Why not? Do you believe that in every case that a large cylinder head/small camshaft is the best case scenario in all scenarios?

Who said, a mild camshaft? I hope you are not just comparing .050" numbers or lift numbers. This is a fraction of the importance. It is the lobe that determines the mildness. But then again, what is "mild."?

Do you? Does anybody FULLY understand?

.... do YOU really understand what you just posted?... or are you now going the rainbow style?

Here's a little insight on how to better performance/solve problems.

1. More air or A/F DOES = more power.

2. If you solve the first part of the equation (= getting more air into the cylinders), you now proceed to the processing portion of that air in the cylinders.... that does not mean you limit the air it may reach the cylinders due to OTHER "post processing" handicaps.

3. IOW.... get the "air" there, then solve for its "usage" problems.

4. We haven't reached the "top end" yet, or how can you reach it, if you cannot make the setup process the added air?

5. Solve for #4 THEN concentrate on the "top end".

6. YES.....a "large cylinder head/small camshaft is the best case scenario in all scenarios"... if you know what you're doing...... the OEM found out, they're using it, and continue to learn.

7. What is a mild camshaft?...... .... would a setup allowing the use of power brakes, A/C, cruise control, making 20+ MPG while also being able to cross the 1320' in 11 seconds do?.... or have RESULTS taken a secondary importance role?

8. I know I do "FULLY understand", and continue to learn BTW, with stuff I have to work on a daily basis.... not hearsay, nor guesses.

clement · Mar 17, 2009

95Vert383AOD said:
Ah i understand...Bigger head means it moves the power band up. So assuming you had the right Pistons to clear valves. Then you could run a radical cam that would allow a 302 to Rev. to 8500. Wouldn't be too nice of a street vehicle. but with like a 4.56 gear and high stall Converter it would make it rev. to that 8500 sweet spot faster and awesome track car. Excuse me if im wrong....ive had a few beers and am not done

But now on the other End you could cram the air in with a super charger meaning the motor wouldnt have to rev. so high because the air it would take 8500rpm to move can be crammed in with less RPM.

Im just pretending i was an air molecule with no place to go ....how would i flow? I would flow at really high RPM's at a .750 lift on AFR 205's bolted to a 302 (Race Block of course)

look back in the posts. i gave a basement range for peak airspeed. its no where near 8500 rpm. even with a blower you can only have so much airspeed before reversion occurs.

95Vert383AOD · Mar 17, 2009

Sorry it was the beer ...oops ::BURP::

joel5.0 · Mar 17, 2009

5spd GT said:
Apples to Oranges.

Two intake valves act VERY different than one 2.02" valve.

Did I bring up anything about a 2.08" being to large? What about the possiblity of valve/cylinder wall air flow interference? What about the amount of material that would need to be removed with a stock forged/hyper piston?

Would not, the camshaft specs have to be a band-aid because of the limited clearance/cutting that could occur to fully utilize an AFR 205 cc head.

Do the MCSA, velocity profiles, shapes, curves, etc. have any effect on what an engine needs?

How accurate are advertised numbers? Let's get a scope of the entire lobe to peak lift.

Would not that variable valve timing help with it's "low-end" and supplement the high end as well? Can you have your cake and eat it to, with variable valve timing?

Small plenums = large TB's + intake tract and vice versa. By the way, who brought up TB's? Does one not realize that they are not at all related to a CARB?

What is the point of the tapered TB?

I would hardly call the Lincoln LS a luxury car. Rented one, one time.

Who said it is to large? Is this taking comment out of context?

Allow me to call this as it is.... plain and simple ..... or are you now going to explain that a person that has two jobs + studies in an university, is going to spend his limited budget "renting" a Lincoln LS?... OK!... let me say it a little more specific then.... have you worked on LS Lincoln engines 2002+? ... or does View attachment 265996"renting" something make you an "expert"? ... I must be an expert mason then.

Did you bring what?...... the 2.08" intake valve?.... the 2-valves over one?.... etc, etc, etc....... Don't you see the obvious... again.... the OBVIOUS intention of that setup (238 CID DOHC multi-valve cylinder head small camshaft events in a luxury car) is to INCREASE the amount of A/F processed in the engine.... by cylinder, by cycle, by event? .... regardless of the means to achieve it? Of course two valves are different than one, does that mean the goal also changes?

Apples to Oranges? .... isn't the Lincoln LS an Otto 4-cycle engine?..... if it IS, does it follow the exception not the rule clause?..... if so.... what about the '07 Ford Explorer SOHC 4.0L engine.... or is that another "exception" to the rule? Would I rather beat a 454 BBC with a pro stock sounding 302 sbf or a stock sounding 302 clevor?..... #2 please. Have I done it?...... "I Rented one, one time".....NOT.

Why were TB's, intake setups, MAF, etc brought up?..... isn't the whole combo what's important?.... not one single concept, parameter, metric, component, part?

What is the point of the tapered TB?..... .... but please, explain the other case where it's "un-tapered"...... in a SUV...... been reading anh?....

5spd GT · Mar 17, 2009

joel5.0 said:
Allow me to call this as it is.... plain and simple ..... or are you now going to explain that a person that has two jobs + studies in an university, is going to spend his limited budget "renting" a Lincoln LS?... OK!... let me say it a little more specific then.... have you worked on LS Lincoln engines 2002+? ... or does View attachment 265995"renting" something make you an "expert"? ... I must be an expert mason then.

Did you bring what?...... the 2.08" intake valve?.... the 2-valves over one?.... etc, etc, etc....... Don't you see the obvious... again.... the OBVIOUS intention of that setup (238 CID DOHC multi-valve cylinder head small camshaft events in a luxury car) is to INCREASE the amount of A/F processed in the engine.... by cylinder, by cycle, by event? .... regardless of the means to achieve it? Of course two valves are different than one, does that mean the goal also changes?

Apples to Oranges? .... isn't the Lincoln LS an Otto 4-cycle engine?..... if it IS, does it follow the exception not the rule clause?..... if so.... what about the '07 Ford Explorer SOHC 4.0L engine.... or is that another "exception" to the rule? Would I rather beat a 454 BBC with a pro stock sounding 302 sbf or a stock sounding 302 clevor?..... #2 please. Have I done it?...... "I Rented one, one time".....NOT.

Why were TB's, intake setups, MAF, etc brought up?..... isn't the whole combo what's important?.... not one single concept, parameter, metric, component, part?

What is the point of the tapered TB?..... .... but please, explain the other case where it's "un-tapered"...... in a SUV...... been reading anh?....

Looks like I struck a nerve.

By the way, when you are out of state without a ride, you rent a car. Want to know the other one I have had to rent? That LS was slow, lol.

Well, off to submit some work.

FastDriver · Mar 17, 2009

I'm pretty sure that you guys are only impressing yourselves with your techno-BS.

Seriously, this guy is trying to run AFR205s on a stock block and you guys are getting into another pissing contest about cam theory, fluid dynamics, and Lincoln LS's.

The bottom line is that on a stock 302 block (read: will not be taken to 8000+rpm) AFR205s are not going to be an optimum selection, even if they can make good power with a well-chosen cam.

Given a stock block with stock internals, a stock rev-limiter (or at least the limitations of stock internals), and any cylinder head of your choice with a matching cam and intake, no one would rationally start out with an AFR205 head. Stop muddling the point or confusing the issue for guys that are just looking for straight answers.

The OP's question was answered long ago, and this thread is going down the drain.

Chris

afr 205's on stock 302

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