[Scott Roberts]

So what rpm does ur motor peak at?

[J.C.you]

Originally Posted by Scott Roberts

So what rpm does ur motor peak at?

CSA determines peak among with other factors including stroke, which I am sure you are aware of. The motor we are still working on is a class motor, built for a specific purpose, hopefully to have an advantage with current rules in that class. I don't think it is a fair assumption that because this engine currently peaks at 8100 or so means a shorter stroke build would do likewise.

I see no reason one could not take a 3.5 stroke or so with a 4.5 bore, a short valve v head such as Lynn's with the pushrod out of the port, move the cam lobes and lifter bores to straighten the angles and make power to 10k.
Would it make comparable power as a symmetrical port head? No, but to blankly say a tunnel port cannot make power past 9200 is not a good thing to publicly post. You may have to eat a cyber post.

[mike leech]

I wonder how that would taste?

[Half-Inch Stud]

Originally Posted by mike leech

I wonder how that would taste?

HaHa hayagot a racecar?

Seriously Mike that deserves a Doubleclick Link. not gonna do. nooot gonna doit.

[mike leech]

Originally Posted by Half-Inch Stud

HaHa hayagot a racecar?

Seriously mike that deserves a Doubleclick. not gonna do. nooot gonna doit.

If I say yes, are you going to post one of those butthurt songs?

[J.C.you]

Originally Posted by mike leech

I wonder how that would taste?

That was the G rated version. I could have said cyber sheite.

[mike leech]

Originally Posted by J.C.you

That was the G rated version. I could have said cyber sheite.

I'm not at all curious how that might taste.

[Pont428]

Originally Posted by J.C.you

CSA determines peak among with other factors including stroke, which I am sure you are aware of. The motor we are still working on is a class motor, built for a specific purpose, hopefully to have an advantage with current rules in that class. I don't think it is a fair assumption that because this engine currently peaks at 8100 or so means a shorter stroke build would do likewise.

I see no reason one could not take a 3.5 stroke or so with a 4.5 bore, a short valve v head such as Lynn's with the pushrod out of the port, move the cam lobes and lifter bores to straighten the angles and make power to 10k.
Would it make comparable power as a symmetrical port head? No, but to blankly say a tunnel port cannot make power past 9200 is not a good thing to publicly post. You may have to eat a cyber post.

He definitely will eat that one JC. They will do push rod in first to see what power it makes. Air is Air, it doesnt know what RPM the engine is. Why dont we just wait and see? I remember when everyone said a 4.5 bore wasnt possible, and here you are JC! Lynn is doing close to 4.6 bore for me.

[Transporter]

Originally Posted by Pont428

He definitely will eat that one JC. They will do push rod in first to see what power it makes. Air is Air, it doesnt know what RPM the engine is. Why dont we just wait and see? I remember when everyone said a 4.5 bore wasnt possible, and here you are JC! Lynn is doing close to 4.6 bore for me.

Pont428, can I assume that to get close to 4.6 you are stagger bored? and also what do you think your thinnest wall section will be?

Just curious,

Thanks Stan

[Scott Roberts]

Originally Posted by Pont428

He definitely will eat that one JC. They will do push rod in first to see what power it makes. Air is Air, it doesnt know what RPM the engine is. Why dont we just wait and see? I remember when everyone said a 4.5 bore wasnt possible, and here you are JC! Lynn is doing close to 4.6 bore for me.

1) You guys are hell bent on me eatting something...weird..

2) I hope it doesnt have this kind of angularity on the push rods.. see pic below

3) Whole lot more to it then that...

4) I said that in my last post but everyone is still acting butt hurt and insisting I will be eating something still. See bold statement #1.

5) I wish both you and J.C. the best on your combos. I hope they perform as expected.

[Stan Weiss]

Originally Posted by Scott Roberts

1) You guys are hell bent on me eatting something...weird..

2) I hope it doesnt have this kind of angularity on the push rods.. see pic below

3) Whole lot more to it then that...

4) I said that in my last post but everyone is still acting butt hurt and insisting I will be eating something still. See bold statement #1.

5) I wish both you and J.C. the best on your combos. I hope they perform as expected.

Scott,
That only shows why in one of these thread I ask about how much the lifter bores could be moved and J.C. answered. But do not remember how much they were moved.

Stan

[BruceWilkie]

Originally Posted by Stan Weiss

Scott,
That only shows why in one of these thread I ask about how much the lifter bores could be moved and J.C. answered. But do not remember how much they were moved.

Stan

I'm guesstimating that intake pushrod is off center approx 1.25" .... To straighten that out means move the intake lifter bore centers the same amount... offsetting the lifter cup plays havoc on the roller and Crower told me beyond .150" is not a good idea...they dont like any offset whenever possible. The exhaust is also offset in that pic just not highlighted it isnt as severe. So your definately talking major block changes and a new cam core to run the big port at very high rpm reliably.

[J.C.you]

Originally Posted by BruceWilkie

I'm guesstimating that intake pushrod is off center approx 1.25" .... To straighten that out means move the intake lifter bore centers the same amount... offsetting the lifter cup plays havoc on the roller and Crower told me beyond .150" is not a good idea...they dont like any offset whenever possible. The exhaust is also offset in that pic just not highlighted it isnt as severe. So your definately talking major block changes and a new cam core to run the big port at very high rpm reliably.

Bruce, the port is close to 4.6 csa now with no mods to the lifter bore other than the liners. For a small cube motor such as the 445 I mentioned to achieve the target rpm of 10k before choke we would only need a port with approx. 4 csa. Definitely a smaller/narrower port and less, if any angle needed after moving the lifter bores and camshaft lobes. I believe there is enough meat in the existing IA block to get there.

[BruceWilkie]

Originally Posted by Pont428

He definitely will eat that one JC. They will do push rod in first to see what power it makes. Air is Air, it doesnt know what RPM the engine is. Why dont we just wait and see? I remember when everyone said a 4.5 bore wasnt possible, and here you are JC! Lynn is doing close to 4.6 bore for me.

And fuel is fuel, it doesnt know what the rpm of the engine is either...

Besides dealing with the inertia differences of those two, there are other factors that affect both in how they behave and arrive in the cylinder in a good homogenous mix ready to burn. Its not just csa and adequate airflow thru the lift curve.

I think Tony was smart to move the pushrod out of JC's port... Not that he couldnt have made more space around the pushrod (or a port divider) for same csa...
One just cant divide the port part of the way or all the way from intake plenum to the valve seat without consideration of ALL factors that need to occur or could occur. Then not forget the factors that occur between the throttle and the valve, across the valves during overlap and things that are occuring before and after valves open and close on both sides of the head.

JMO but for JC's build requirements I think Tony chose a way to meet the build requirement and avoid alot of additional and costly R+D. Job well done!

This proposed 406 with 2.7 to 3.0 hp per ci mentioned earlier... if it is tried with the pushrod through the port there will be air/fuel issues to address differently than a "conventional" open port. (maybe direct cylinder injection helps???)
If the pushrod is run outside the port its going to take block changes among other things to build a valvetrain that can hold up to the rpm you are going to turn a 406 to the amount of rpm required to move all the air it would take for 2.7-3.0 hp per ci.

Seriously, good luck with this. Thats a heck of a goal!

Please understand Im NOT anti RAV... I think its a very cool choice for street, street-strip, serious brackets, even high level type builds to a point... but I think there is very good reason why its not in use in Pro-stock.

Lots of great talent amongst us... it would be awesome if "we" (as an affiliated group of Pontiac diehards) showed the other brand guys the way...